EASY
AS and A Level
IMPORTANT
Earn 100

There is an electric current in a wire of mass per unit length40 gm-1• The wire is placed in a magnetic field of strength 0.50 T and the current is gradually increased until the wire just lifts off the ground. What is the value of the current when this happens?

a 0.080A

b 0.20A

c 0.78 A

d 780A

Important Questions on Magnetic Fields and Electromagnetism

EASY
AS and A Level
IMPORTANT

A current-carrying wire is placed in a uniform magnetic field.

(a) Describe how the wire should be placed to experience the
maximum force due to the magnetic field.

EASY
AS and A Level
IMPORTANT

A current-carrying wire is placed in a uniform magnetic field.

(b) Describe how the wire should be placed to experience no force due to the magnetic field .

EASY
AS and A Level
IMPORTANT

A current-carrying conductor placed at right angles to a uniform magnetic field experiences a force of4.70×10-3N. Determine the force on the wire when, separately:

(a) the current in the wire is increased by a factor of3.0

EASY
AS and A Level
IMPORTANT

A current-carrying conductor placed at right angles to a uniform magnetic field experiences a force of4.70×10-3N. Determine the force on the wire when, separately:

(b) the magne tic flux density is halved

EASY
AS and A Level
IMPORTANT

A current-carrying conductor placed at right angles to a uniform magnetic field experiences a force of4.70×10-3N. Determine the force on the wire when, separately:

(c) the length of the wire in the magnetic field is reduced to 40%
of its original length.

EASY
AS and A Level
IMPORTANT

A copper wire carrying a current of1.2A has 3.0cm of its length placed in a uniform magnetic field, as shown.

Question Image

The force experienced by the wire is 3.8×10-3N when the angle between the wire and the magnetic field is50°.

(a) Calculate the magnetic flux density.

EASY
AS and A Level
IMPORTANT

A copper wire carrying a current of 1.2A has 3.0cm of its length placed in a uniform magnetic field, as shown.

Question Image

The force experienced by the wire is3.8×10-3Nwhen the angle between
the wire and the magnetic field is50°.

(b) State the direction of the force experienced by the wire.

EASY
AS and A Level
IMPORTANT

This diagram shows a view from above of two long, parallel strips of aluminium foil,A and B, carrying a current downwards into the paper.

Question Image

(a) On a copy of the diagram, draw the magnetic field around and between the two strips.