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]

A coil with 200 turns has a flux linkage of 10 Wb. If the number of turns is reduced to 100, the new flux linkage will be:

A. 5 Wb

B. 10 Wb

C. 20 Wb

D. 40 Wb

The unit of magnetic flux is:

A. Tesla

B. Weber

C. Joule

D. Ampere

A coil is rotated in a magnetic field, inducing an EMF. If the coil is rotated faster:

A. The induced EMF will decrease.

B. The induced EMF will remain the same.

C. The induced EMF will increase.

D. The coil will stop inducing EMF.

Which of the following best describes Lenz's Law?

A. It determines the magnitude of the induced EMF.

B. It determines the direction of the induced EMF.

C. It determines the frequency of the induced EMF.

D. It determines the phase of the induced EMF.

A metal rod is moved through a magnetic field. The induced EMF in the rod will be maximum when the rod moves:

A. Parallel to the magnetic field lines.

B. Perpendicular to the magnetic field lines.

C. At an angle of 30° to the magnetic field lines.

D. At an angle of 45° to the magnetic field lines.

a) What are eddy currents and how are they produced? [3]

b) Describe one application and one disadvantage of eddy currents. [2]

c) How can the effects of eddy currents be minimised in transformers? [3]

a) Explain the principle of superposition as it applies to electric fields. [3]

b) If two point charges, +Q and -Q, are placed at points A and B respectively, describe the resultant electric field at a point equidistant from both charges. [3]

c) How does the electric field change if the distance between the charges is halved? [2]

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

b) A coil with 200 turns is placed in a magnetic field of strength 0.05 T. If the area of the coil is 0.02 m^2 and the angle between the magnetic field and the normal to the coil is 30°, calculate the magnetic flux linked with the coil. [3]

c) If the coil is rotated such that the angle changes to 60° in 0.1 seconds, determine the induced EMF. [4]

d) Explain how the direction of the induced EMF can be determined using Lenz's law. [2]

a) Describe the phenomenon of electromagnetic induction. [2]

b) A straight conductor of length 1.5 m moves perpendicular to a magnetic field of 0.04 T with a speed of 3 m/s. Calculate the induced EMF in the conductor. [3]

c) How would the induced EMF change if the conductor moves parallel to the magnetic field? [2]

d) State and explain the factors on which the magnitude of induced EMF in a moving conductor depends. [4]

a) What are eddy currents? [2]

b) Explain the principle behind the working of a Faraday cage. [3]

c) A metal block is placed in a region with a rapidly changing magnetic field. Describe the effects of eddy currents on the block. [3]

d) How can the adverse effects of eddy currents be reduced in electrical machines? [3]