# Moving Charges And Magnetism

15 Questions | Total Attempts: 1461  Settings Create your own Quiz Time: 30 Minute

• 1.
A wire is placed parallel to the lines of force in mangnetic field and current flows in the wire. Then
• A.

The wire will experience a torque

• B.

The wire will experience a force along the direction of magnetic field

• C.

The wire will not experience any force

• D.

The wire will experience a perpendicular force.

• 2.
A circular coil of radius 4 cm and 20 turns carries a current of 3A. It is placed in a magnetic field of induction 0.5T. The magnetic dipole moment of the coil is
• A.

0.6Am2

• B.

0.45 Am2

• C.

0.3 Am2

• D.

0.15 Am2

• 3.
Currents of 10 ampere and 2 ampere are passed through two parallel wires A and B respectively in opposite directions. If the wire A is infinitely long and the length of the wire B is 2m. The force acting on the conductor B, which is situated at 10 cm distance form A will be
• A.

8 X 10–5N

• B.

5 X 10–5N

• C.

8π X 10–7N

• D.

4π X 10–7N

• 4.
To convert a galvanometer into an ammeter, we connect
• A.

Low resistance in series

• B.

Low resistance in parallel

• C.

High resistance in series

• D.

High resistance in parallel

• 5.
Two parallel conductors are carrying current 'i' in the same direction. Force experienced per unit length by each conductor (distance between the conductors is r) would be
• A.

Repulsion and

• B.

Repulsion and

• C.

Attraction and

• D.

Attraction and

• 6.
If a particle is moving in a uniform magnetic field, then
• A.

Its momentum changes but total energy ramains the same

• B.

Both momentum and total energy remains the same

• C.

Its total energy changes but momentum remains same

• D.

Both momentum and tatal energy will change

• 7.
A particle A has charge + q and a particle B has charge + 4q with each of them having the same mass m. When allowed to fall from rest through the same electric potential difference, the ratio of their speeds u/ uB will therefore:
• A.

2 : 1

• B.

1 : 2

• C.

1 : 4

• D.

4 : 1

• 8.
E, F and G are three current carrying linear conductors. The direction of net magnetic force on F will be
• A.

In the direction of current flowing in F

• B.

In the plane of paper towards left

• C.

In the plane of paper towards right

• D.

Normal to the plane of paper

• 9.
An electron is moving along the positive X-axis. You want to apply a magnetic field for a short times so that the electron may reverse its direction and move parallel to the negative X-axis. This can be done by applying the magnetic field along
• A.

X-axis only

• B.

Y-axis only

• C.

Z-axis only

• D.

Y and Z axes

• 10.
A proton moving with a constant velocity passes through a region of space without change in its velocity. If E and B represent electric and magnetic fields respectively, this region of space may not have
• A.

E ≠ 0, B = 0

• B.

E ≠ 0, B ≠ 0

• C.

E = 0, B ≠ 0

• D.

E = 0, B = 0

• 11.
Two identical magnetic dipoles of magnetic moment 1.0 A m2 each, placed at a separation of 2 m with their axes perpendicular to each other. The resultant magnetic field at a point midway between the dipoles is
• A.

T

• B.
• C.
• D.
• 12.
When a charged particle enters in a uniform magnetic field, its kinetic energy
• A.

Remains constant

• B.

Increases

• C.

Decreases

• D.

Becomes zero

• 13.
A galvanometer of resistance 100 Ω gives full scale deflection for 20 mV. Find the resistance to be attached so that it gives full scale deflection of 5V.
• A.

in parallel

• B.

in Series

• C.

in parallel

• D.

in Series

• 14.
Two insulating rings, one of slightly smaller diameter than the other are suspended along their common diameter as shown. Initially the planes of the rings are mutually perpendicular. When a steady current is set up in each of them
• A.

The two rings rotate into a common plane

• B.

The inner ring oscillates about its initial position

• C.

The inner ring stays stationary while the outer one moves into the plane of the inner ring

• D.

The outer ring stays stationary while the inner one moves into the plane of the outer ring

• 15.
A bar magnet has a magnetic moment , and is placed in a magnetic field of 0.2 T. work done in turning the magnet from parallel to anti parallel position relative to the field direction is
• A.

0.5 J

• B.

1 J

• C.

2.0 J

• D.

Zero

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