Deck 8: Magnetism and Electromagnetism

Question 1

Consequence of motor effect is

A)electromagnetic induction
B)current
C)voltage
D)e.m.f

Answer 1

electromagnetic induction

Question 2

Total number of magnetic field lines passing through an area is called

A)magnetic flux density
B)magnetic flux
C)e.m.f
D)voltage

Answer 2

magnetic flux

Question 3

Magnitude of induced e.m.f is proportional to

A)rate of change of current
B)rate of change of voltage
C)rate of change of magnetic flux linkage
D)rate of change of resistance

Answer 3

rate of change of magnetic flux linkage

Question 4

In transformer, the core is made up of soft iron in order to pass the maximum

A)flux
B)current
C)magnetic flux
D)voltage

Question 5

For a straight wire, induced current depends upon

A)the speed of movement of wire
B)the length of wire
C)the magnitude of magnetic flux density
D)all of above

Question 6

In generators, the rate of change of flux linkage is maximum when the coil is moving through the

A)vertical position
B)horizontal position
C)diagonal position
D)at an angle of 45°

Question 7

E.M.F for a coil depends upon

A)the cross sectional area
B)no. of turns of wire
C)the magnitude of magnetic flux density
D)all of above

Question 8

Currents that flow in circles inside a disc are known as

A)eddy currents
B)circular currents
C)air currents
D)alternating curents

Question 9

When field is parallel to plane of area, magnetic flux through coil is

A)zero
B)infinite
C)2
D)5

Question 10

Moving a coil in and out of magnetic field induces

A)force
B)potential difference
C)e.m.f
D)voltage

Question 11

Induced current in coil by a magnet turns it into an

A)straight wire
B)magnet
C)ammeter
D)electromagnet

Question 12

Strength of magnetic field is known as

A)flux
B)density
C)magnetic strength
D)magnetic flux density

Question 13

Unit of luminous intensity is

A)m
B)kg
C)cd
D)mol

Question 14

For a hydrogen atom the electrical force as compared to gravitational force is{{}}

A)10³⁹ times
B)10 ⁴⁰ times
C)10 ⁴¹ times
D)10 ⁴² times

Question 15

Weakest force in nature is

A)electric force
B)gravitational force
C)weak force
D)magnetic force

Question 16

Magnetic field can be produced by using

A)permanent magnet
B)electric current
C)temporary magnet
D)both A and B

Question 17

Whenever there is force on magnetic pole, there exists

A)magnetic field
B)electric field
C)current
D)voltage

Question 18

If the magnetic flux density and current are at right angles, then component of force acting on the conductor is

A)BIL cosθ
B)BIL sinθ
C)BIL tanθ
D)BL sinθ

Question 19

Unraveling an electromagnetic gives

A)stronger field
B)weaker field
C)moderate field
D)wider field

Question 20

Force per meter on two wires carrying a current of 1 A placed 1 m apart is equal to {{}}

A)6.7 × 10^-11 N
B)9.0 × 10 ⁹ N
C)2.0 × 10 ^-7N
D)3.0 × 10^-4 N

Question 21

F = BIL can only be used if the magnetic field and electric current are

A)at right angles to each other
B)in same direction
C)anti-parallel to each other
D)anti-perpendicular to each other

Question 22

Derived unit Tesla is related to

A)A
B)kg
C)s
D)all of above

Question 23

If we reverse the direction of electric current, then the direction of magnetic field will be

A)reversed
B)remains same
C)becomes tangent
D)becomes normal

Question 24

1 Tesla is equal to {{}}

A)50 N A^-1 m^-1
B)100 N A^-1 m^-1
C)1 N A^-1 m^-1
D)1000 N A^-1 m^-1

Question 25

Field which does not have magnetic poles is

A)straight lined
B)normal to the wire
C)tangent to the wire
D)circular