11.1 Electromagnetic Induction

A coil with 100 turns is placed in a magnetic field. The magnetic flux through the coil changes from 0 to 5 Wb in 2 seconds. What is the induced EMF in the coil?

A. 250 mV

B. 2.5 V

C. 25 V

D. 250 V

According to Lenz's Law, the direction of the induced current in a coil is such that it:

A. Increases the cause producing it.

B. Decreases the cause producing it.

C. Is always clockwise.

D. Is always anti-clockwise.

A conductor is moving perpendicular to a magnetic field. If the speed of the conductor is doubled, the induced EMF will:

A. Remain the same.

B. Double.

C. Halve.

D. Quadruple.

Eddy currents are:

A. Currents induced in a solid metal block.

B. Currents that flow in a circular path.

C. Currents that flow in a straight line.

D. Direct currents produced by a battery.

Which of the following is NOT an application of eddy currents?

A. Induction cooking.

B. Magnetic braking in trains.

C. Electromagnetic shielding.

D. Charging a smartphone.

a) Describe Faraday's observations that led to the concept of electromagnetic induction. [3]

b) Define magnetic flux and state its unit. [2]

a) State Faraday's law of electromagnetic induction. [3]

b) If the magnetic flux through a coil changes by 0.05 Wb in 0.1 seconds, calculate the induced EMF in the coil. [2]

a) Explain Lenz's law and its significance in the context of conservation of energy. [3]

b) A coil is placed near a magnet. If the north pole of the magnet is moved towards the coil, what will be the direction of the induced current in the coil? [2]

a) Describe the relationship between magnetic flux linkage and the number of turns in a coil. [2]

b) If a coil with 100 turns experiences a change in magnetic flux of 0.02 Wb in 0.5 seconds, calculate the induced EMF. [3]

c) How would the induced EMF change if the number of turns in the coil were doubled? [2]

a) Compare the similarities and differences between gravitational fields and electric fields. [3]

b) Define electric potential and state its unit. [2]

c) How is work done related to a change in electric potential? [3]