Physics MCQs with Answers

10:11:00 Unknown 1 Comments

1.the displacement of the spot light on the scale is proportional to the angle of deflection provided the angle of deflection is
a. small
b. large
c. much larger
d. infinite

2.in pivoted type galvanometer, a light pointer used to read the angle of deflection of the coil is made of
a. steel
b. tungsten
c. copper
d. aluminum

3.soft iron is preferred to copper as a core of a transformer because
a. soft iron is easily magnetized and demagnitized
b. iron is less conducting than copper
c. iron is cheaper
d. all

4.eddy currents are the induced currents which are set up
a. along the flux lines
b. in a direction perpendicular to the flux
c. out of flux area
d. only around the core

5.the gradient of potential along the conductor of length L moving across a magnetic field is given by
a. delta V/L
b. L/ delta V
c. L * delta V
d. delta v +- L

6.the strength of magnetic field is called
a. tesla
b. magnetic induction
c. emf
d. none

7.transformer make possible the
a. conversion of ac voltage to dc voltage
b. conversion of dc voltage to ac voltage
c. conversion of ac voltage to ac voltage
d. conversion of dc voltage to dc voltage

8.lenz law predicts
a. the direction of induced current
b. the direction of induced e.m.f
c. the magnitude of induced current
d. the magnitude of induced e.m.f

9.A.c cannot be used for
a)producing heat
b)producing light
c)magnetizing and electroplatting
d)all

10.an induced emf of a coil is independent of
a. time
b. resistance of the circuit
c. the number of turns in the coil
d. the change in magnetic flux

11.one of the following will not increase the voltage produced by an AC generator. which one is it?
a. increasing the number of turns on the coil
b. increasing the speed of rotation
c. increasing the strength of the magnetic field
d. increasing the size of the gap in which the coil rotates

12.it is possible to transmit A.C power over long distances without much power loss by
a. transformers
b. commutators
c. armatures
d. thermistors

13.inside a house, the transformers used are
a. step down
b. step up
c. both
d. none

14.when the number of turns in the coil is doubled without any change in the length of the coil, its self inductance becomes
a. 4 times
b. 2 times
c. halved
d. remains unchanged

15.Which of the following works on torque on the current carrying conductor placed in magnetic field
a)Galvanometer
b)ammeter
c)voltmeter
d)all

16.magnetic shielding to a magnetic instrument is provided by covering with
a. soft iron of high permeability
b. a metal of high conductivity
c. a plastic material
d. any one of above

17.if the motor is overloaded beyond its limits, the current
a. would become zero
b. could be so high that it may burn the motor out
c. would me smaller
d. all conditions can occur

18.when a conductor is rotated in a direction perpendicular to a magnetic field then its free electrons
a. move opposite to field direction
b. remain stationary
c. move in the field direction
d. move at right angle to field direction

19.The practical illustrations of the phenomenon of mutual induction is
a)Ac generator
b)Dc dtnamo
c)motor
d)transformer

20.the current produced by moving a loop of wire across a magnetic field is called
a. direct current
b. magnetic current
c. alternating current
d. induced current
e. none

21.Inductors act as a short circuit for
a)Ac
b)Dc
c)Both a and b
d)none

22.an emf is set up in a conductor when it
a. is kept in a magnetic field
b. is kept in an electric field
c. moves in a magnetic field
d. both a n b

23.hysteresis loss is the
a. energy expanded
b. work done
c. amount of charge
d. both a n c
e. both a n b

24.VsA-1 is known as
a. weber
b. henry
c. tesla
d. watt

25.when a conductor is moved across a magnetic field, both the electrostatic force Fe and the magnetic force Fm are set up. when the system reaches equilibrium state, then
a. Fe>Fm
b. Fe=Fm
c. Fe=-Fm
d. Fe<Fm

26.heating a magnet will
a. weak it
b. strengthen it
c. reverse its polarity
d. have no effect

27.The average power dissipation in a pure capacitor in AC circuit is
a.1/2CV2
B.CV2
C.2CV2
D.zero

28.what type of current is essential for normal transformer operation
a. a low current
b. a high current
c. a direct current
d. an alternating current

29.if a step up transformer were efficient, the primary and secondary windings would have the same
a. current
b. power
c. no. of turns
d. voltage

30.a pair of slip rings is used in
a. a.c generator
b. d.c generator
c. a.c motor
d. d.c motor

31.the energy resides in a current carrying conductor in the form of
a. magnetic field
b. electrostatic field
c. gravitational field
d. all

32.A dynamo converts
a)mechanical energy to electrical energy
b)electrical energy to mechanical energy
c)magnetic energy into electrical energy
d)all

33.When the motor is at its maximum speed , then back emf will be
a)Maximum
b)zero
c)intermediate values
d)no back emf

34.A.c cannot be used for
a)Producing heat
b)ammeter
c)voltmeter
d)all

35.all the magnetic materials lose their magnetic properties when
a. dipped in water
b. dipped in oil
c. brought near a piece of iron
d. heated

36.which quantity is increased in step down transformer?
a.current
b.voltage
c.power
d.frequency

37.the source of magnetic field is a/an
a. current loop
b. static electric charge
c. isolated magnetic pole
d. none

38.For long distances the transformer used is
a)step down
b)input voltage and output voltage remains same
c)step up
d)amplifier is used

39.Emf generated by A.C dynamo depends upon
a)no of turns in the coil
b)magnetic field strength
c)frequency rotation
d)all

40.lenz law is equivalent to law of conservation of
a. energy
b. momentum
c. charge
d. mass

41.Weber is a unit of
a)magnetic field intensity
b)magnetic induction
c)magnetic flux
d)self inductance

42.Which of the following functions like motor
a)galvanometer
b)ammeter
c)voltmeter
d)all
Ans key
1a     11d    21b    31a     41c
2d     12a    22c    32a     42 d
3a     13a    23e    33a           
4b     14a    24b    34d              
5a     15d    25c    35d             
6b     16a    26a    36a                  
7c     17b    27d    37a                     
8a     18d    28d    38a                    
9c     19d    29b    39d             
10b    20d    30a    40a        



I am Mechatronics and Control Engineer from UET, Lahore. Helping Engineering students gives me pleasure.

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