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RRB ALP Relevant Trade Questions

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RRB ALP Relevant Trade Questions

RRB ALP Relevant Trade Questions

shape Introduction

RRB ALP and Technician 2018 Recruitment has 2 stages of computer based test. The article RRB ALP Relevant Trade Questions makes an attempt to present the different types of questions that can be expected for the Relevant Trade Questions section of CBT Stage 2. Below mentioned are the details.

shape CBT Stage 2

CBT Stage 2: Short listing of Candidates for the Second Stage CBT exam shall be based on the normalized marks obtained by them in the First Stage CBT Exam. The Second Stage CBT shall have two parts viz Part A and Part B as detailed below:

Part A
This test would be of 90 minutes duration consisting of 100 questions, 4 sections as follows.

S.No Sections No. of Questions Time allocated
1 Mathematics 100 90 minutes
2 General Intelligence and Reasoning
3 Basic Science and Engineering
4 General awareness on current affairs

Part B
This test would be of 60 minutes duration consisting of 75 questions.

This part is qualifying in nature and shall have questions from the trade syllabus prescribed by Director General of Employment & Training (DGET). Candidates holding Degree, Diploma and HSC (10+2) having eligibility for the posts of ALP have to select relevant trade from the list of trades listed against their engineering discipline/HSC (10+2).

The trade syllabus can be obtained from the DGET website. The relevant trades for various engineering discipline/HSC (10+2) for appearing in the qualifying test is as below:

Click Here – For DGET website

S.No Engineering Discipline(Diploma/Degree) Relevant trade for PART B Qualifying Test to be selected from
1 Electrical Engineering
and combination of
various streams of
Electrical Engineering
Electrician / Instrument Mechanic / Wiremen
/Winder(Armature) / Refrigeration and Air
Conditioning Mechanic
2 Electronics Engineering
and combination of
various streams of
Electronics Engineering
Electronics Mechanic / Mechanic Radio & TV
3 Mechanical Engineering
and combination of
various streams of
Mechanical Engineering
Fitter / Mechanic Motor Vehicle / Tractor
Mechanic / Mechanic Diesel / Turner /
Machinist / Refrigeration and Air
Conditioning Mechanic/ Heat Engine /
Millwright Maintenance Mechanic
4 Automobile Engineering
and combination of
various streams of
Automobile Engineering
Mechanic Motor Vehicle / Tractor Mechanic /
Mechanic Diesel / Heat Engine /
Refrigeration and Air Conditioning Mechanic
5 HSC(10+2) with
Physics and Maths
Electrician / Electronics Mechanic / Wireman

shape Samples

The Relevant Trade Questions section in CBT Stage 2 for RRB ALP & Technician Recruitment has Different type of questions:

Below Provided are some of the Sample Questions with stream wise.

1. Find the current in the circuit.

    a) 10 A
    b) 20 A
    c) 30 A
    d) 40 A

Answer: Option (b)
I=V/R. Total resistance = 20+40=60ohm. I=120V. I=120/60=20A.

2. The resistivity of the conductor depends on

    a) area of the conductor.
    b) length of the conductor.
    c) type of material.
    d) none of these.

Answer: Option (c)
The resistivity is a property of material, defined as the resistance between two opposite faces of a cube of a material of unit volume. That is why resistivity is only the unique property of material and it does not depend upon the dimension of any piece of material.

3. The resistance of a conductor of diameter d and length l is R Ω. If the diameter of the conductor is halved and its length is doubled, the resistance will be

    a) R Ω
    b) 2R Ω
    c) 4R Ω
    d) 8R Ω

Answer: Option (d)
As per law of resistance, the resistance of the conductor is inversely proportional to its cross-sectional area i.e. it is inversely proportional to the square of the diameter of cross-sectional area of the conductor. As per same law of resistance, the resistance of the conductor is directly proportional to the length of the conductor.

4. How many coulombs of charge flow through a circuit carrying a current of 10 A in 1 minute?

    a) 10
    b) 60
    c) 600
    d) 1200

Answer: Option (c)
1 Ampere current means flowing of 1 Coulomb charge per second. That means 10 A current in 1 minute or 60 seconds implies 10 × 60 = 600 coulombs.

5. A capacitor carries a charge of 0.1 C at 5 V. Its capacitance is

    a) 0.02 F
    b) 0.5 F
    c) 0.05 F
    d) 0.2 F

Answer: Option (a)
The capacitance of a capacitor is expressed by Q/V. Where Q is the charge of the capacitor and V is the voltage across the capacitor.

6. To obtain a high value of capacitance, the permittivity of dielectric medium should be

    a) low
    b) zero
    c) high
    d) unity

Answer: Option (c)

7. Four capacitors each of 40 µF are connected in parallel, the equivalent capacitance of the system will be

    a) 160 µF
    b) 10 µF
    c) 40 µF
    d) 5 µF

Answer: Option (a)
The impedance of a capacitor is inversely proportional to its capacitance value. Reciprocal of equivalent impedance of parallel connected circuit elements is sum of reciprocal of impedance of each of the elements.

8. Instantaneous power in inductor is proportional to the

    a) product of the instantaneous current and rate of change of current.
    b) square of instantaneous current.
    c) square of the rate of change of current.
    d) temperature of the inductor.

Answer: Option (a)
The instantaneous voltage across the inductor is expressed as the product of inductance and rate of change of current through it. Power is expressed as the product of current and voltage. Hence instantaneous power in an inductor is proportional to the product of instantaneous current and rate of change of current through it.

9. If all the elements in a particular network are linear, then the superposition theorem would hold, when the excitation is

    a) DC only
    b) AC only
    c) Either AC or DC
    d) An Impulse

Answer: Option (c)
Superposition theorem can be applied for both AC as well DC excitation to calculate the voltage or current calculations. It holds for both DC and AC excitation, if the circuit is linear. But superposition theorem is not applicable for power calculations.

10. In balanced bridge, if the positions of detector and source are interchanged, the bridge will still remain balanced. This can be explained from which theoem

    a) Reciprocity theorem
    b) Thevinin’s theorem
    c) Norton’s theorem
    d) Compensation theorem

Answer: Option (a)
When response to excitation is constant even though we interchange the excitation and responses then the reciprocity theorem is verified for the given network.

11. If field current is decreased in shunt dc motor, the speed of the motor

    a) Remains same.
    b) Increases.
    c) Decreases.
    d) None of the above.

Answer: Option (b)
As a shunt field current If decreases, φ also decreases and the speed rises as speed is inversely proportional to flux.

12. What is the shunt resistance component equivalent circuit obtained by no load test of an induction motor representative of?

    a) windage and friction loss
    b) core loss only
    c) both 1 and 2
    d) Copper loss

Answer: Option (b)
No load loss consists of core loss, friction and windage loss and no load copper loss. But shunt branch resistance Rc in the induction motor equivalent circuit does not represent the no load losses, it represents only the core loss of the induction motor.

13. Eddy current loss will depends on

    a) Frequency
    b) Flux density
    c) Thickness
    d) All of the above

Answer: Option (d)

14. The emf induced in the dc generator armature winding is

    a) AC
    b) DC
    c) AC and DC
    d) None of the above

Answer: Option (a)
The emf induced in the dc generator armature winding is AC, but we need DC current from DC generator, so to convert this AC current to DC current mechanical rectifier called as commutator is used.

15. Commutator in DC generator is used for

    a) collecting of current
    b) reduce losses
    c) increase efficiency
    d) convert AC armature current in to DC

Answer: Option (d)
Commutator is used as mechanical rectifier in DC machines. It converts AC armature current in to DC current.

16. Length of the cable is doubled, its capacitance C will be

    a) One-fourth.
    b) One-half.
    c) Doubled.
    d) Unchanged.

Answer: Option (c)
The length of the cable and the capacitance of the cable are directly proportional to each other. Hence, if the length gets doubled, then the capacitance also can be doubled.

17. Which of the following rotor is used in thermal power plants?

    a) cylindrical rotor
    b) salient pole rotor
    c) either of these
    d) squirrel cage rotor

Answer: Option (a)
Cylindrical rotor is also called as round rotor or smooth rotor, there is no projection, there closed portions contain field winding which is distributed and unslotted portion also acts as poles. It has large axial length and small diameter, resulting high peripheral speed. As the air gap is uniform throughout the machine it is more suitable for high speed operation, employed in all thermal, nuclear power plants containing turbo alternators with two or maximum 4 poles only.

18. Lowest critical frequency is due to pole and it may be present origin or nearer to origin, then it is which type of network?

    a) LC
    b) RL
    c) RC
    d) Any of the above

Answer: Option (c)
In RC network lowest critical frequency is due to pole and it is at origin or nearer to origin depending on the value of the capacitance value and transfer function.

19. Which system is also known as automatic control system?

    a) open loop control system
    b) closed loop control system
    c) either 1 or 2
    d) nether 1 nor 2

Answer: Option (b)
Control system in which the output has an effect upon the input quantity in order to maintain the desired output value are called closed loop control system. The open loop system can be modified as closed loop system by providing a feedback. The provision of feedback automatically corrects the changes in output due to disturbances. Hence the closed loop control system is also called as automatic control system.

20. By using which of the following elements, mechanical translational systems are obtained?

    a) mass element
    b) spring element
    c) dash-pot
    d) all of the above

Answer: Option (d)
The model of mechanical translational systems can be obtained by using three basic elements mass, spring and dash-pot. These three elements represents three essential phenomena which occur in various ways in mechanical systems.

21. Which devices used to measure the temperature of an object?

    a) Poteintiometer
    b) Odometer
    c) Thermometers
    d) Galvanometer

Answer: Option (c)
A thermometer is a device that measures temperature or temperature gradient.

22. For audio frequency applications, the popular oscillator used is

    a) Wien bridge oscillator
    b) Hartley oscillator
    c) Crystal oscillator
    d) Phase shift oscillator

Answer: Option (a)
Characteristics like ease of tuning, very low distortion and good frequency stability of Wien bridge oscillator makes it becomes popular for audio frequency applications. Phase shift oscillator and Wien bridge oscillator both can be used as audio frequency range. But Wien bridge oscillator can be used for very wide frequency range.

23. Which of the following is not a sinusoidal oscillator?

    a) LC oscillator
    b) RC phase shift oscillator
    c) Relaxation oscillator
    d) Crystal oscillator

Answer: Option (c)
Relaxation oscillator is basically a non-sinusoidal oscillator which is used to generate square, triangular or pulse waveforms. The rest of the oscillators are sinusoidal oscillators producing sinusoidal output.

24. Relaxation Voltage controlled oscillators are used to generate

    a) Sinusoidal wave
    b) Triangular wave
    c) Sawtooth wave
    d) Both B and C

Answer: Option (d)
Relaxation VCOs can be employed to generate both triangular and saw-tooth waveforms.

25. In an electric room heat converter the method of heating used is

    a) Infrared heating.
    b) Induction heating.
    c) Resistance heating.
    d) Arc heating.

Answer: Option (c)
An electric room heat converter is a heater which operates by air covection currents ciculating through the body of the appliacne and across its heating elements. The resistance heating is provided to it. This heats up the air, causing it to increase it to increase in volume and so become buoyant and rise.

1. To implement the linear time invariant recursive system described by the difference equation y(n)=\(\displaystyle\sum_{k=1}^{N} a_k y(n-k)+\displaystyle\sum_{k=0}^{M}b_kx(n-k)\)
in Direct form-I, how many number of delay elements and multipliers are required respectively?

    a) M+N+1,M+N
    b) M+N-1,M+N
    c) M+N,M+N+1
    d) None of the mentioned

Answer: Option (c)
Explanation: From the given equation, there are M+N delays, so it requires M+N number of delay elements and it has to perform M+N+1 multiplications, so it require that many number of multipliers.

2. The system represented by the following direct form structure is:

    a) General second order system
    b) Purely recursive system
    c) Partial recursive system
    d) FIR system

Answer: Option (d)
The output of the system according to the direct form given is
y(n)= b0x(n)+b1x(n-1)+b2x(n-2)
Since the output of the system is purely dependent on the present and past values of the input, the system is called as FIR system.

3. Which of the following should be done in order to convert a continuous-time signal to a discrete-time signal?

    a) Sampling
    b) Differentiating
    c) Integrating
    d) None of the mentioned

Answer: Option (a)
The process of converting a continuous-time signal into a discrete-time signal by taking samples of continuous time signal at discrete time instants is known as ‘sampling’.

4. The process of converting discrete-time continuous valued signal into discrete-time discrete valued(digital) signal is known as:

    a) Sampling
    b) Quantization
    c) Coding
    d) None of the mentioned

Answer: Option (b)
In this process, the value of each signal sample is represented by a value selected from a finite set of possible values. Hence this process is known as ‘quantization’

5. The difference between the unquantized x(n) and quantized xq(n) is known as:

    a) Quantization coefficient
    b) Quantization ratio
    c) Quantization factor
    d) Quantization error

Answer: Option (d)
Quantization error is the difference in the signal obtained after sampling i.e., x(n) and the signal obtained after quantization i.e., xq(n) at any instant of time.

6. Which bit coder is required to code a signal with 16 levels?

    a) 8 bit
    b) 4 bit
    c) 2 bit
    d) 1 bit

Answer: Option (b)
To code a signal with L number of levels, we require a coder with (log L/log 2) number of bits. So, log16/log2=4 bit coder is required.

7. What is the spectrum that is obtained when we plot |ck| as a function of frequency?

    a) Magnitude voltage spectrum
    b) Phase spectrum
    c) Power spectrum
    d) None of the mentioned

Answer: Option (a)
We know that, Fourier series coefficients are complex valued, so we can represent ck in the following way.
When we plot |ck| as a function of frequency, the spectrum thus obtained is known as Magnitude voltage spectrum.

8. Which of the following is used in the realization of a system?

    a) Delay elements
    b) Multipliers
    c) Adders
    d) All of the mentioned

Answer: Option (d)
From each set of equations, we can construct a block diagram consisting of an interconnection of delay elements, multipliers and adders.

9. Computational complexity refers to the number of:

    a) Additions
    b) Arithmetic operations
    c) Multiplications
    d) None of the mentioned

Answer: Option (d)
Computational complexity is one of the factor which is used in the implementation of the system. It refers to the numbers of Arithmetic operations (Additions, multiplications and divisions).

10. Which of the following refers the number of memory locations required to store the system parameters, past inputs, past outputs and any intermediate computed values?

    a) Computational complexity
    b) Finite world length effect
    c) Memory requirements
    d) None of the mentioned

Answer: Option (c)
Memory requirements refers the number of memory locations required to store the system parameters, past inputs, past outputs and any intermediate computed values.

11. From the given circuit below, we can conclude that.

    a)BJT ispnp
    b)BJT is npn
    c)transistor is faulty
    d)not possible to determined

Answer: Option (c)
According to figure, both the LED is glowing, which indicate that circuit is complete in both the half cycle of a.c. signal.
Therefore Emitter and Base junction will act as short circuit in both direction, which indicate transistor is faulty.

12. A pole zero pattern of a certain filter is shown in figure. This filter must be


Answer: Option (d)
In transfer function, no of zeros = no. of poles, hence it is all pass fliter.

13. At room temperature the current in an intrinsic semiconductor is due to

    a) holes
    b) electrons
    c) ions
    d) holes and electrons

Answer: Option (d)
Intrinsic material has equal number of holes and electrons.

14. In which of these is reverse recovery time nearly zero?

    a) Zener diode
    b) Tunnel diode
    c) Schottky diode
    d) PIN diode

Answer: Option (c)
In schottky diode there is no charge storage and hence almost zero reverse recovery time.

15. Which of the following is used for generating time varying wave forms?

    a) MOSFET
    b) PIN diode
    c) Tunnel diode
    d) UJT

Answer: Option (d)
Its output is used to trigger SCR.

16. The voltage across a zener diode

    a) is constant in forward direction
    b) is constant in reverse direction
    c) is constant in both forward and reverse directions
    d) none of the above

Answer: Option (b)
Zener diode is always reverse biased.

17. Which one most appropriate dynamic system?

    a) y(n) + y(n – 1) + y(n + 1)
    b) y(n) + y(n – 1)
    c) y(n) = x(n)
    d) y(n) + y(n – 1) + y(n + 3) = 0

Answer: Option (a)
Because present output of y(n) depend upon past y(n – 1) and future y(n + 1).

18. A voltage V(t) is a Gaussian ergodic random process with a mean of zero and a variance of 4 volt2. If it is measured by a dc meter. The reading will be

    a) 0
    b) 4
    c) 2
    d) 2

Answer: Option (a)
DC meter reads mean value.

19. If 60 J of energy are available for every 15 C of charge, what is the voltage?

    a) 15 V
    b) 0.25 V
    c) 4 V
    d) 60 V

Answer: Option (c)

20. The negative and positive charge symbols are assigned (in that order) to the:

    a) atom and nucleus
    b) electron and proton
    c) proton and electron
    d) electron and element

Answer: Option (b)

21. An atom’s atomic number is determined by the number of:

    a) protons
    b) electrons
    c) neutrons minus protons
    d) neutrons

Answer: Option (a)

22. Which resistive component is designed to be temperature sensitive?

    a) Thermistor
    b) Rheostat
    c) Photoconductive cell
    d) Potentiometer

Answer: Option (a)

23. In a TV receiver the colour killer:

    a) Cuts off the chromastages during monochrome reception
    b) Ensures that no colour is transmitted to monochrome receivers
    c) Prevents colour overloading
    d) Makes sure that the colour burst is not mistaken for sync pulses

Answer: Option (a)

24. Solution to the blind speed problem is to

    a) Change the Doppler frequency
    b) Vary the PRF
    c) Use monopulse
    d) Use MTI

Answer: Option (b)

25. The Doppler frequency increases as the target

    a) Approaches the radar
    b) Recedes the radar
    c) Moves perpendicular to the beam
    d) Does not depend on the target velocity

Answer: Option (a)

26. The bandwidth of a radar receiver is inversely proportional to the

    a) Pulse width
    b) Pulse repetition frequency
    c) Pulse interval
    d) Square root of the peak transmitted power

Answer: Option (a)

27. A TR tube is used

    a) To protect the high power transmitter
    b) To protect receiver
    c) To avoid arcing in waveguides
    d) For None of these of the above

Answer: Option (b)

28. The parabolic reflector antenna are generally used to

    a) Provide high gain
    b) Provide pencil beam
    c) Increase bandwidth of operation
    d) None of these

Answer: Option (b)

29. After a target has been acquired the best scanning system for tracking is

    a) Nodding
    b) Spiral
    c) Conical
    d) Helical

Answer: Option (c)

30. Microwave links repeaters are typically 50KM apart

    a) Because of atmospheric attenuation
    b) Because of output tube power limitations
    c) Because of Earth’s curvature
    d) To ensure that the applied voltage is not excessive

Answer: Option (c)

31. One of the following is not used as a microwave mixer or detector

    a) Crystal diode
    b) Schottky ” barrier diode
    c) Backward diode
    d) PIN diode

Answer: Option (d)

32. The Doppler frequency increases as the target

    a) Approaches the radar
    b) Recedes the radar
    c) Moves perpendicular to the beam
    d) Does not depend on the target velocity

Answer: Option (a)

33. Primary batteries, unlike secondary batteries, may be:

    a) charged once
    b) recharged over and over
    c) used once
    d) stored indefinitely

Answer: Option (c)

34. If the current in a circuit equals 0 A, it is likely that the

    a) resistance is too low
    b) voltage is too high
    c) circuit has a short
    d) circuit is open

Answer: Option (d)

35. Which part of an atom has no electrical charge?

    a) Proton
    b) Electron
    c) all
    d) Neutron

Answer: Option (d)

1. The peak value of a sine wave is 200 V. Its average value is

    a) 127.4 V
    b) 141.4 V
    c) 282.8 V
    d) 200V

Answer: Option (a)

2. Two waves of the same frequency have opposite phase when the phase angle between them is

    a) 360°
    b) 180°
    c) 90°
    d) 0°

Answer: Option (b)

3. The best place to install a capacitor is

    a) very near to inductive load
    b) across the terminals of the inductive load
    c) far away from the inductive load
    d) any where

Answer: Option (b)

4. Inductance affects the direct current flow

    a) only at the time of turning off
    b) only at the time of turning on
    c) at the time of turning on and off
    d) at all the time of operation

Answer: Option (c)

5. The double energy transient occur in the

    a) purely inductive circuit
    b) R-L circuit
    c) R-C circuit
    d) R-L-C circuit

Answer: Option (d)

6. The absolute thermodynamic temperature scale is also known as

    a) celsius scale
    b) kelvin scale
    c) fahrenheit scale
    d) none of the mentioned

Answer: Option (b)
It was proposed by Kelvin.

7. In defining the temperature scale, the standard reference point is taken as

    a) zero kelvin
    b) boiling point of water
    c) triple point of water
    d) none of the mentioned

Answer: Option (c)
Triple point of water is taken as the standard reference point.

8. If the temperature of intake air in internal combustion engine increases, then its efficiency will

    a) Remain same
    b) Decrease
    c) Increase
    d) None of these

Answer: Option (b)

9. The operation of forcing additional air under pressure in the engine cylinder is known as

    a) Scavenging
    b) Turbulence
    c) Supercharging
    d) Pre-ignition

Answer: Option (c)

10. The mean effective pressure obtained from engine indicator indicates the

    a) Maximum pressure developed
    b) Minimum pressure
    c) Instantaneous pressure at any instant
    d) Average pressure

Answer: Option (d)

11. The probability of knocking in diesel engines is increased by

    a) High self ignition temperature
    b) Low volatility
    c) Higher viscosity
    d) All of these

Answer: Option (d)

12. In compression ignition engines, swirl denotes a

    a) Haphazard motion of the gases in the chamber
    b) Rotary motion of the gases in the chamber
    c) Radial motion of the gases in the chamber
    d) None of the above

Answer: Option (b)

13. Supercharging is the process of

    a) Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere
    b) Providing forced cooling air
    c) Injecting excess fuel for raising more loads
    d) Supplying compressed air to remove combustion products fully

Answer: Option (a)

14. The property of a material by which it can be beaten or rolled into thin plates, is called

    a) Malleability
    b) Plasticity
    c) Ductility
    d) Elasticity

Answer: Option (a)
A material can be beaten into thin plates by its property of malleability.

15. The materials which have the same elastic properties in all directions, are called

    a) Isotropic
    b) Brittle
    c) Homogeneous
    d) Hard

Answer: Option (a)
Same elastic properties in all direction are called the homogenity of a material.

16. What kind of elastic materials are derived from a strain energy density function?

    a) Cauchy elastic materials
    b) Hypo elastic materials
    c) Hyper elastic materials
    d) None of the mentioned

Answer: Option (c)
The hyper elastic materials are derived from a strain energy density function. A model is hyper elastic if and only if it is possible to express the cauchy stress tensor as a function of the deformation gradient.

17. What is the effect of increased carbon content on chilled cast iron?

    a) Chilling depth increases
    b) Hardness of chilled zone increases
    c) Both a. and b.
    d) None of the above

Answer: Option (b)

18. Rosettes of tempered carbon in the matrix of ferrite are observed in the microstructure of

    a) gray cast iron
    b) spheroidal cast iron
    c) malleable cast iron
    d) none of the above

Answer: Option (c)

19. Pump transfers input mechanical energy of an engine, into ___

    a) pressure energy of a fluid
    b) kinetic energy of a fluid
    c) both a. and b.
    d) none of the above

Answer: Option (c)

20. Low-torque high-speed motors are used in

    a) cranes
    b) winches
    c) fans
    d) all of the above

Answer: Option (c)

21. In which of these pumps, swash plate is replaced by cylinder block?

    a) bent axis piston pump
    b) radial piston pump
    c) axial piston pump
    d) none of the above

Answer: Option (a)

22. In axial piston pump, the yoke is pushed away from cylinder block due to which

    a) yoke angle increases
    b) swash plate angle decreases
    c) both a. and b.
    d) none of the above

Answer: Option (a)

23. Which type of body is an airfoil?

    a) streamline body
    b) wave body
    c) bluff body
    d) induced body

Answer: Option (a)

24. The highest point of syphon is called as

    a) syphon top
    b) summit
    c) reservoir
    d) none of the above

Answer: Option (b)

25. The cylindrical portion of short length, which connects converging and diverging section of venturimeter, is called as

    a) diffuser
    b) connector
    c) throat
    d) manometer tube

Answer: Option (c)

26. Which cutting condition affects the cutting temperature predominantly?

    a) depth of cut
    b) cutting speed
    c) feed
    d) none of the above has any effect on cutting temperature

Answer: Option (b)

27. Which fixtures are used for machining parts which must have machined details evenly spaced?

    a) Profile fixtures
    b) Duplex fixtures
    c) Indexing fixtures
    d) None of the above

Answer: Option (c)

28. Several machine tools can be controlled by a central computer in

    a) NC (Numerical Control) machine tool
    b) CNC (Computer Numerical Control) machine tool
    c) DNC (Direct Numerical Control) machine tool
    d) CCNC (Central-Computer Numerical Control) machine tool

Answer: Option (c)

29. In which process the material is removed due to the action of abrasive grains?

    a) Electro-Chemical Grinding (ECG)
    b) Ultrasonic Machining (USM)
    c) Laser Beam Machining (LBM)
    d) Electrical Discharge Machining (EDM)

Answer: Option (b)

30. What is the ratio of amplitude of response to that of the input called?

    a) Response
    b) Gain
    c) Phase
    d) Frequency

Answer: Option (b)

31. The type of memory which is fast and temporarily stores the data which are immediately required for use is called as

    a) HDD
    b) ROM
    c) RAM
    d) SSD

Answer: Option (c)

32. Data acquisition of all the physical quantities in the real world is done in

    a) the analog mode
    b) the digital mode
    c) either analog mode or digital mode
    d) none of the above

Answer: Option (a)

33. What are the factors affecting selection of casting process?

    a) Tolerances
    b) Surface finish
    c) Both a. and b.
    d) None of the above

Answer: Option (c)

34. Which belt conveyor prevents sliding down of material at an inclination of 55o with horizontal?

    a) Flat belt conveyor
    b) Troughed belt conveyor
    c) Blanket belt conveyor
    d) Woven wire belt conveyorsc

Answer: Option (c)

35. The angle between normal stress and tangential stress is known as angle of __

    a) declination
    b) orientation
    c) obliquity
    d) rotation

Answer: Option (c)

1. The function of crankcase in two stroke petrol engines is

    a) It holds the engine lubricating oil
    b) It forms a pressurised chamber for fuel air mixture
    c) It holds the exhaust gases after combustion
    d) None of the mentioned

Answer: Option (b)
It holds the fuel air mixture during engine cycle.

2. Connecting rods are generally of the following form

    a) Forged I-section
    b) Forged round section
    c) Cast iron square section
    d) Forged square section steel

Answer: Option (a)
Connecting rods are generally of forged I-section type.

3. The purpose of crankcase ventilation is to

    a) Cool the oil
    b) Remove vaporised water and fuel
    c) Supply oxygen to the crankcase
    d) It assists in maintaining the viscosity of oil

Answer: Option (b)
Crankcase ventilation removes vaporised water and fuel.

4. The escape of burned gases from the combustion chamber past the pistons and into the crankcase is called

    a) Gas loss
    b) Blow by
    c) By pass
    d) Passed gas

Answer: Option (b)
Blow by is the surging of burned gases from combustion chamber into the crankcase.

5. Piston compression rings are made of

    a) Cast iron
    b) Steel
    c) Aluminium
    d) Bronze

Answer: Option (a)
Cast iron is used for piston compression rings.

6. The purpose of a piston pin is that

    a) It prevents the valve from rotating
    b) It links the connecting rod to the crankshaft
    c) It ensure the piston ring to the piston
    d) It connect the piston to the connecting rod

Answer: Option (d)
Piston pin connects the piston to the connecting rod.

7. Passenger car engines contain

    a) 2 compression ring and 1 oil control ring
    b) 2 compression ring and 2 oil control ring
    c) 1 compression ring and 1 oil control ring
    d) 2 compression ring and no oil control ring

Answer: Option (a)
These type of engines contain 2 compression ring and 1 oil control ring.

8. The plate which acts as a packing between cylinder block and cylinder head is called

    a) Chaplet
    b) Liner
    c) Gasket
    d) Flange

Answer: Option (c)
Gasket forms the packing between cylinder block and cylinder head

9. Which one of the following is a type of Gasket

    a) Copper asbestos
    b) Steel asbestos
    c) Single sheet rigid
    d) All of the mentioned

Answer: Option (d)
All the three are various types of gaskets.

10. The opening and closing of a valve is respectively done by

    a) A cam and a spring
    b) A spring and a cam
    c) Gas pressure and cam
    d) Cylinder vacuum and spring

Answer: Option (a)
An engine valve is opened by a cam and closed by a spring.

11. A relief valve is fitted to the main oil gallery of an engine. The purpose of this valve is to

    a) Limit the maximum oil pressure
    b) Open when the oil is hot
    c) Maintain the supply if the gallery becomes blocked
    d) Stop the oil flow to the bearings

Answer: Option (a)
Relief valve limits the maximum oil pressure.

12. Which of the following is not a part of the transmission system

    a) Clutch
    b) Axles
    c) Wheels
    d) Gear box

Answer: Option (c)
Wheels are considered a part of the automobile chassis.

13. The loads supported by an automobile frame are

    a) Weight of the body, passengers and cargo loads
    b) Torque from engine and transmission
    c) Sudden impacts from collisions
    d) All of the mentioned

Answer: Option (c)
Supporting all the above mentioned loads is a basic function of an automobile frame.

14. What are ‘Wings’ of a vehicle

    a) Spoilers at the front of a vehicle
    b) Spoilers at the rear of a vehicle
    c) Spoilers at the sides of a vehicle
    d) Spoilers at the top of a vehicle

Answer: Option (b)
Spoilers located at the rear of a vehicle are known as Wings.

15. The central portion of the wheel is called

    a) Rim
    b) Scale
    c) Hub
    d) Axle

Answer: Option (c)
The central portion of the wheel is called ‘hub’.

16. ‘Volkswagen Polo’ is a

    a) Ultra-compact car
    b) Sub-compact car
    c) Compact car
    d) Executive car

Answer: Option (b)
Volkswagen Polo is a sub-compact car.

17. Which of these is a compact executive car

    a) Mercedes-Benz S Class
    b) Audi A8
    c) Audi A4
    d) Mercedes-Benz E Class

Answer: Option (c)
Audi A4 is a compact executive car.

18. What is actual power delivered by the engine known as?

    a) Shaft power
    b) Horse power
    c) Brake power
    d) None of the mentioned

Answer: Option (c)
The power delivered by the engine is called brake power.

19. The force that opposes the motion of a vehicle is

    a) Rolling resistance
    b) Gradient resistance
    c) Wind or air resistance
    d) All of the mentioned

Answer: Option (d)
Rolling resistance, gradient resistance and air resistance all oppose the motion of a vehicle.

20. Rolling resistance doesnot depend on which of the following factors

    a) Load on each road wheel
    b) Radius of driving wheel
    c) Wheel inflation pressure
    d) Nature of road surface

Answer: Option (b)
Rolling resistance does not depend on radius of driving wheel.

21. The value of coefficient of air resistance for average cars is approximately equal to

    a) 0.32
    b) 0.032
    c) 0.0032
    d) 1.32

Answer: Option (c)
For average cars, value of coefficient of air resistance is approx 0.0032.

22. A heat engine converts heat energy from fuel combustion or any other source into which type of work

    a) Electrical work
    b) Mechanical work
    c) Pressure work
    d) None of the mentioned

Answer: Option (b)
A heat engine gives mechanical work as output.

23. Thermal power plants operate on which of these cycles

    a) Otto cycle
    b) Rankine cycle
    c) Carnot cycle
    d) Stirling cycle

Answer: Option (b)
Thermal power plants operate on Rankine cycle.

24. The efficiency of a combined cycle gas turbine(steam cooled) can range as high as

    a) 20%
    b) 30%
    c) 40%
    d) 60%

Answer: Option (d)
A steam cooled combined cycle gas turbine can have efficiency as high as 60%.

25. The material known as high carbon high copper chrome silicon cast steel is used for making

    a) Camshaft
    b) Cylinder body
    c) Cylinder head
    d) Piston

Answer: Option (a)
Material used for making camshafts is high carbon high copper chrome silicon cast steel.

26. Crankshafts are usually constructed by

    a) Casting
    b) Drop forging
    c) Drawing
    d) Extrusion

Answer: Option (b)
Drop forging is used for making crankshafts.

27. The main causes of crankshaft vibration are

    a) Variation in torque
    b) Cyclic variation of gas and combustion products
    c) Unbalanced weight of parts
    d) All of the mentioned

Answer: Option (d)
Crankshaft vibration is caused by all the above mentioned causes.

28. In an automobile engine the temperature of the piston will be more at

    a) The crown of the piston
    b) The skirt of the piston
    c) The piston walls
    d) The piston rings

Answer: Option (a)
The crown of the engine experiences the highest temperature.

29. Ignition advance is expressed in terms of

    a) Crank angle
    b) Millimetres of piston travel before TDC
    c) Time in milli seconds
    d) All of the mentioned

Answer: Option (d)
Ignition advance can be expressed in terms of any of the following.

30. In internal combustion engine the approximate percentage of the combustion heat that passes to the cylinder walls is

    a) 5%
    b) 10%
    c) 30%
    d) 60%

Answer: Option (c)
Approximately 30% of heat passes to the cylinder walls.

31. A single cylinder four stroke engine is rotating at 2000 rpm. The number of power strokes occuring in one minute is

    a) 500
    b) 1000
    c) 2000
    d) 4000

Answer: Option (b)
For every two revolutions one cylse is completed in a four stroke engine. If speed is 2000 rpm then number of complete cycles per minute is 1000.

32. In a four stroke engine each cylinder has

    a) One valve
    b) Two valves
    c) Three valves
    d) Four valves

Answer: Option (b)
A four stroke engine cylinder has one intake and one exhaust valve.

33. In a diesel engine the fuel injection pressure is in the range

    a) 100 to 170 atm
    b) 60 to 70 atm
    c) 30 to 40 atm
    d) 20 to 25 atm

Answer: Option (a)
The pressure of fuel injection is very high for a diesel engine

34. The device used to measure the clearance between the valve and tappet of an IC Engine is

    a) Feeler gauge
    b) Snap gauge
    c) Slip gauge
    d) Micrometer

Answer: Option (a)
A Feeler gauge is used to measure the clearance.

35. On modern four stroke engines the exhaust valve opens just

    a) Before TDC
    b) After TDC
    c) Before BDC
    d) After BDC

Answer: Option (c)
Exhaust valve opens before the piston reaches Bottom Dead Centre.

1. What is the maximum limit of sound intensity in decibel units beyond which a human being cannot hear?

    a) 80 decibel
    b) 85 decibel
    c) 90 decibel
    d) 95 decibel

Answer: Option (b)

2. Who proposed the ‘Wave Theory’ of light?

    a) Huygens
    b) Albert Einstein
    c) Isaac Newton
    d) Thomas Edison

Answer: Option (a)

3. If a bar magnet is broken into two pieces, then

    a) one piece will have North Pole on both ends and other piece will have South Pole on both ends
    b) only longer piece will behave as bar magnet
    c) each piece will remain a magnet with North Pole at one end and South Pole at the other end
    d) both pieces will lose their magnetism

Answer: Option (c)

4. Why does a corked bottle filled with water break when frozen

    a) glass is a bad conductor of heat
    b) the bottle contracts on freezing
    c) volume of water decreases on freezing
    d) volume of water increases on freezing

Answer: Option (d)

5. Wood is the primary raw material for the manufacture of:

    a) paint
    b) paper
    c) ink
    d) gun powder

Answer: Option (b)

6. Spondylitis is a disease that affects:

    a) liver
    b) intestine
    c) spinal column
    d) brain cells

Answer: Option (c)

7. What is the chemical name of laughing gas?

    a) Carbon monoxide
    b) Sulphur dioxide
    c) Hydrogen peroxide
    d) Nitrous Oxide

Answer: Option (d)

8. The filament of an electric bulb is made up of which material?

    a) tungsten
    b) iron
    c) stainless steel
    d) graphite

Answer: Option (a)

9. Diamond is an allotropic form of:

    a) Uranium
    b) Carbon
    c) Silicon
    d) Sulphur

Answer: Option (b)

10. The mass on any substance liberated from an electrolyte is directly proportional to the quantity of charge passing through the solution.

    a) Avogadro’s law
    b) Faraday’s first law of electrolysis
    c) Stefan’s law
    d) Kirchhoff’s law of electricity

Answer: Option (b)

11. The value of Avogadro’s constant is?

    a) 6.022 × 10²³ per mole
    b) 58.04 × 10¯² per mole
    c) 69.51 × 10¯¹⁸ per mole
    d) 6.022 × 10¹⁴ per mole

Answer: Option (a)

12. Which one of the following is the correct unit of angular velocity?

    a) m/minute
    b) cm/sec²
    c) cm/sec
    d) radians/sec

Answer: Option (d)

13. The maximum displacement of a vibrating body from its mean position is called?

    a) Gyration
    b) Wavelength
    c) Amplitude
    d) Impulse

Answer: Option (c)

14. The Kinetic energy of a body depends upon?

    a) Mass, gravity and height
    b) Its mass alone
    c) Its velocity alone
    d) Both mass and velocity

Answer: Option (d)

15. The term ‘Squirrel cage’ is associated with?

    a) Pressure gauges
    b) Coils
    c) Potentiometers
    d) Induction motors

Answer: Option (d)

16. A swimmer finds it easier to swim in sea water than in plain water, why?

    a) Sea water has less contamination.
    b) Sea waves help a swimmer to swim.
    c) Sea water has higher density than plain water.
    d) Sea has a much higher volume of water.

Answer: Option (c)

17. The temperature on the surface of the sun is about?

    a) 8 × 10¹⁵ °C
    b) 500 °C
    c) 6000 °C
    d) 1000°C

Answer: Option (c)

18. As a train approaches us, the frequency or shrillness of its whistle increases. The phenomenon is explained by?

    a) Big Bang Theory
    b) Doppler effect
    c) Charles law
    d) Archimedes Principle

Answer: Option (b)

19. The load on a spring per unit deflection is called?

    a) Stress
    b) Flexibility
    c) Stiffness
    d) Strain

Answer: Option (c)

20. Which one of the following is a major constituent of petrol?

    a) Pentane (C₅H₁₂)
    b) Octane (C₈H₁₈)
    c) Methane (CH₄)
    d) Hexane (C₆H₁₄)

Answer: Option (b)

21. The sound waves in the audible range have frequencies in the range of?

    a) 20 Hz to 20,000 Hz
    b) 0.5 Hz to 5 Hz
    c) 1 Hz to 10 Hz
    d) 20,000 Hz to 40,000 Hz

Answer: Option (a)

22. The term EURO-II in the context of modern cars refers to?

    a) Emission from cars
    b) Speed of cars
    c) Fuel efficiency
    d) Torque available

Answer: Option (a)

23. Particles which can be added to the nucleus of an atom without changing its chemical properties are :

    a) electrons
    b) protons
    c) neutrons
    d) alpha-particles

Answer: Option (c)

24. “Soap helps in the cleaning of cloths because “

    a) It reduces surface tension
    b) It increases surface tension
    c) It absorbs the dirt
    d) Of some other reason

Answer: Option (a)

25. “Which waves are used in sonography “?

    a) Microwaves
    b) Sound waves
    c) Infrared waves
    d) Ultrasonic waves

Answer: Option (d)

26. When the matter is cooled to very low temperature, it will form “

    a) semi-conductor
    b) super-conductor
    c) insulator
    d) capacitor

Answer: Option (b)

27. The types of waves produced in a sonometer wire are

    a) transverse progressive
    b) transverse stationary
    c) longitudinal progressive
    d) longitudinal stationary

Answer: Option (b)

28. Stationary waves of frequency 300 Hz are formed in a medium in which the velocity of sound is 1200 m/s. The distance between a node and the neighbouring anti node is

    a) 1 m
    b) 2 m
    c) 3 m
    d) 4 m

Answer: Option (a)

29. In a stationary longitudinal wave, nodes are points of

    a) maximum pressure
    b) minimum pressure
    c) minimum pressure variation
    d) maximum pressure variation

Answer: Option (d)

30. If the ratio of the amplitudes of two waves is 4 : 3, then the ratio of maximum and minimum intensity is

    a) 16 : 9
    b) 1 : 16
    c) 1 : 49
    d) 49 : 1

Answer: Option (d)
\(\frac{I_Max}{I_Min} = \left(\frac{\frac{4}{3}+1}{\frac{4}{3}-1}\right)^2 = \frac{49}{1}\)

31. Which is used in designing ships and submarines?

    a) Charle’s law
    b) Archimedes principal
    c) Boyle’s law
    d) None

Answer: Option (b)

32. Masses of stars and galaxies are usually expressed in terms of:

    a) earth’s mass
    b) solar mass
    c) lunar mass
    d) neutron mass

Answer: Option (b)

33. Which of the following is a scalar quantity?

    a) electric field
    b) magnetic momentum
    c) power
    d) average velocity

Answer: Option (c)

34. Light year is a unit of

    a) Time
    b) Light
    c) Distance
    d) Intensity of light

Answer: Option (c)

35. The absorption of ink by blotting paper involves

    a) capillary action phenomenon
    b) viscosity of ink
    c) siphon action
    d) diffusion of ink through the blotting

Answer: Option (a)

1. The ratio of two numbers is 4:7 and their HCF is 6. Find out their LCM

    a) 164
    b) 168
    c) 174
    d) 184

Answer: Option (b)
The two numbers will be 4*6 =24 and 7*6=42. The LCM of 24 and 42 will be 168

2. The ratio of two numbers is 3:4 and their sum is 560. What is the larger number

    a) 240
    b) 320
    c) 340
    d) 416

Answer: Option (b)
Here 3x+4x=560 or x=80 and the larger number is 320

3. Vacancies for Engineers, Diploma and Artisan were in the ratio of 5:7:8 and it was decided to increase by 40, 50 and 75%. What will be the revised ratio

    a) (3:4:5)
    b) 4:5:6)
    c) (2:3:4)
    d) (5:6:7)

Answer: Option (c)
Let x be the HCF of the existing ratio that the vacancies were 5x, 7x and 8x. Now with the increase, it will become (5x+2x), (7x+3.5x) and 8x+6x) and HCF of these numbers will now become 2:3:4

4. An old man gave away 1/5th of his property to Ram, 1/3rd of the remaining to Shyam and 1/2 of the remaining to Geeta. How much part he is left?

    a) (4/15)
    b) (2/15)
    c) (8/15)
    d) (1/5)

Answer: Option (a)
Let he has x amount of which he gives x/5 to Ram, left 4x/5 and gave 1/3 of this shyam i.e. 4x/15 and left with 8x/15 of which he gave 4x/15 to Geeta and thus left with 4x/15.

5. The condition that does not satisfy the condition of their being congruent is

    a) all three sides equal
    b) all three angles equal
    c) two sides and the angle enclosed are equal
    d) the two angles and the side enclosed by them are equal

Answer: Option (b)
If all the three angles are same, it need not be congruent as the sides can be unequal.

6. What is the relation to find the diagonals of a polygons with number of side as ‘n’

    a) (n²-1)/2 for odd sides and n²/2 for even sides
    b) (n-1)(n-3)/2
    c) (n-2)(n-3)/2
    d) n(n-3)/2

Answer: Option (d)
The relation is given as n(n-3)/2

7. Pythagorean triplets are

    a) 2m, m²-1, m²+1
    b) \m, m²-1, m²+1
    c) 2m, 2m²-1, 2m²+1
    d) 2m, m², m²+1

Answer: Option (a)
Pythagoras triplets are given for any natural number m which is greater than one

8. 6 pipes can fill the tank in 1 hour and 20 minutes. How much time in minutes it will take it to fill by 5 pipes.

    a) 80
    b) 200/3
    c) 96
    d) 106

Answer: Option (c)
6 pipes take 80 minutes than one pipe will take 6*80=480 and five pipe 480/5=96 minutes

9. A can do a piece of work in 15 days and B alone can do it in 10 days. B works at it for 5 days and then leaves. A alone can finish the remaining work in

    a) 2
    b) 2.5
    c) 3.5
    d) 3

Answer: Option (b)
Capacity of A is 1/15 and B is 1/10. Work completed in 5 days is 1/3+1/2=5/6 and 1/6 is remaining which will be completed by A in 15/6 days i.e. 2.5 days

10. By what percentage the interest amount received after six year is more as compared to the amount after five years on Rs. 1000/- compounded at an interest of 10% is given by

    a) 0.1
    b) 0.1001
    c) 0.1002
    d) 0.1003

Answer: Option (a)
Every year the interest is on the accumulated amount consisting of principle and interest and thus it will gain by the interest rate given.

11. Water is pouring into a cuboidal reservoir at the rate of 60 liters per minute. If the volume of reservoir is 108 m3, find the number of hours it will take to fill the reservoir

    a) 1/2 hr
    b) 1800 sec
    c) 1800 hrs.
    d) 30 hrs.

Answer: Option (d)
108 m^3 is 108*10^3 liters and time taken will be by dividing this number by 60 and answer will be in minutes which shall be divided by 60.

12. The height of a triangular base pyramid is 12 m with base area as 24 m. What will be volume of the triangular pyramid in cubic meter?

    a) 96
    b) 144
    c) 288
    d) 72

Answer: Option (a)
Area of triangular pyramid is given by 1/3(Base Area)*height

13. What least value should be replaced by * in 223*431 so the number become divisible by 9

    a) 3
    b) 4
    c) 5
    d) 6

Answer: Option (a)
Number is divisible by 9, if sum of all digits is divisible by 9, so (2+2+3+*+4+3+1) = 15+* should be divisible by 9,
15+3 will be divisible by 9,
So that least number is 3.

14. What is the largest 4 digit number exactly divisible by 88

    a) 9900
    b) 9999
    c) 9988
    d) 9944

Answer: Option (d)
Largest 4 digit number is 9999
After doing 9999 ÷ 88 we get remainder 55
Hence largest 4 digit number exactly divisible by 88 = 9999 – 55 = 9944

15. Simplfy b – [b -(a+b) – {b – (b – a+b)} + 2a]

    a) a
    b) 2a
    c) 4a
    d) 0

Answer: Option (d)

16. 2.09 can be expressed in terms of percentage as

    a) 2.09%
    b) 20.9%
    c) 209%
    d) 0.209%

Answer: Option (c)
While calculation in terms of percentage we need to multiply by 100, so
2.09 * 100 = 209.

17. A batsman scored 120 runs which included 3 boundaries and 8 sixes. What percent of his total score did he make by running between the wickets?

    a) 40%
    b) 50%
    c) 60%
    d) 70%

Answer: Option (b)
Number of runs made by running = 110 – (3 x 4 + 8 x 6)
= 120 – (60)
= 60
Now, we need to calculate 60 is what percent of 120.
=> 60/120 * 100 = 50 %

18. If the cost price is 25% of selling price. Then what is the profit percent.

    a) 150%
    b) 200%
    c) 300%
    d) 350%

Answer: Option (c)
Let the S.P = 100
Then C.P. = 25
Profit = 75
Profit% = 75/25 * 100 = 300

19. A man buys an item at Rs. 1200 and sells it at the loss of 20 percent. Then what is the selling price of that item

    a) Rs. 660
    b) Rs. 760
    c) Rs. 860
    d) Rs. 960

Answer: Option (d)
Here always remember, when ever x% loss,
It means S.P. = (100 – x) % of C.P
When ever x% profit,
it means S.P. = (100 + x)% of C.P
So here will be (100 – x) % of C.P.
= 80% of 1200
= 80/100 * 1200
= 960

20. Rs. 120 are divided among A, B, C such that A’s share is Rs. 20 more than B’s and Rs. 20 less than C’s. What is B’s share

    a) Rs 10
    b) Rs 20
    c) Rs 24
    d) Rs 28

Answer: Option (b)
Let C = x. Then A = (x—20) and B = (x—40).
x + x – 20 + x – 40 = 120 Or x=60.
A: B: C = 40:20:60 = 2:1:3.
B’s share = Rs. 120*(1/6) = Rs. 20

21. Two numbers are respectively 20% and 50% more than a third number. The ratio of the two numbers is

    a) 2:5
    b) 3:5
    c) 4:5
    d) 6:5

Answer: Option (c)
Let the third number be x.
First Number (120/100)*x = 6x/5
Second Number (150/100)*x = 3x/2
Ratio = 6x/5:3x/2
=> 4:5

22. In a mixture 60 litres, the ratio of milk and water 2: 1. If the this ratio is to be 1 : 2, then the quanity of water to be further added is

    a) 20 liters
    b) 30 liters
    c) 50 liters
    d) 60 liters

Answer: Option (d)
Quantity of Milk = 60*(2/3) = 40 liters
Quantity of water = 60-40 = 20 liters
As per question we need to add water to get quantity 2:1
=> 40/(20+x) = 1/2
=> 20 + x = 80
=> x = 60 liters

23. A can do a piece of work in 4 hours. A and C together can do it in just 2 hours, while B and C together need 3 hours to finish the same work. In how many hours B can complete the work?

    a) 10 hours
    b) 12 hours
    c) 16 hours
    d) 18 hours

Answer: Option (b)
Work done by A in 1 hour = 1/4
Work done by B and C in 1 hour = 1/3
Work done by A and C in 1 hour = 1/2
Work done by A,B and C in 1 hour = (1/4)+(1/3) = 7/12
Work done by B in 1 hour = (7/12)–(1/2) = 1/12
=> B alone can complete the work in 12 hour

24. Evaluate \( \sqrt{{248}+\sqrt{64}}\)

    a) 14
    b) 26
    c) 16
    d) 36

Answer: Option (c)
=\( \sqrt{{248}+\sqrt{64}}\)
=\( \sqrt{248+8}\)
=\( \sqrt{256}\)
= 16

25. Find the sum of first 30 natural numbers

    a) 470
    b) 468
    c) 465
    d) 463

Answer: Option (c)
Sum of n natural numbers = \(\frac{n(n+1)}{2}\)
= \(\frac{30(31)}{2}\)
= 465