Electromagnetism Physics Test 01

Total Questions: 21

1 - Which statement is true about the magnetic poles?

A ) unlike pose repel
B ) like poles attract
C ) magnetic poles do not effect each other
D ) a single magnetic poles does not exsit ✅

2 - What is the direction of the magnetic field lines inside a bar magnet?

A ) form north pole to south pole
B ) from south pole to north pole ✅
C ) form side to side
D ) there are no magnetic field lines

3 - The presence of a magnetic field can be detected by a:

A ) small mass
B ) stationary positive charge
C ) stationary negative charge
D ) magnetic compass ✅

5 - D.C motor converts:

A ) mechanical energy into electrical energy
B ) mechanical energy into chemical energy
C ) electrical energy into mechanical energy ✅
D ) electrical energy into chemical energy

6 - Which part of a D.C.motor reverses the direction of current through the coil every half-cycle?

A ) the armature
B ) the commutator ✅
C ) the brushes
D ) the slip rings

8 - The step-up transformer

A ) increases the input current
B ) increases the input voltage ✅
C ) has more turns in the primary
D ) has less turns in the secondary coil

9 - The turn ratios of a transformer is 10.

A ) 1s = 10/ p
B ) Ns = N p / 10
C ) N s = 10N p ✅
D ) Vs = V p /10

11 - Iron core is used in transformer to:

A ) Enhance the flux ✅
B ) decrease the flux
C ) keep flux the same
D ) both a and b

12 - Transformer works on the principle of:

A ) Self induction
B ) Mutual induction ✅
C ) Electrostatic
D ) Induction

13 - Equation for transformer is:

A ) Ns/ vp = Vs/ Ns
B ) Ns/Np = Vp/ Vs
C ) Vs/ Vp = Ns/Np ✅
D ) Vp/Np = Ns/Np

14 - The number of lines of force in a magnetic field depends upon:

A ) Shape of coil
B ) Size of coil
C ) Magnet
D ) Strength of field ✅

16 - The lines will be in the form of concentric circles, if conductor is:

A ) Circular
B ) Straight ✅
C ) Solenoid
D ) None of these

17 - The end of solenoid from which lines of force emerge out is called:

A ) North pole ✅
B ) South pole
C ) North and south pole
D ) None

18 - The end of solenoid from which line of forces enter is called:

A ) North pole
B ) South pole ✅
C ) North and south pole
D ) None

19 - The magnetic field of a solenoid resembles as:

A ) Iron wire
B ) U-shape magnet
C ) Bar magnet ✅
D ) Point charge

20 - A current carrying conductor produces a field around it is called:

A ) Electric field
B ) Magnetic field ✅
C ) Gravitational field
D ) None

21 - According to Flemming's left hand rule the direction of magnetic field is indicated by:

A ) Thumb
B ) Forefinger ✅
C ) Middle finger
D ) Right hand rule