F5-C4 Electromagnetism

Question 1

Define catapult field

Answer 1

The resultant magnetic field produced from the interaction between the magnetic field from a permanent magnet and a current carrying conductor

Question 2

What rule is used to determine the direction of induced FORCE

Answer 2

Fleming’s Left Hand Rule

Question 3

What is the function of split ring commutator in a DC motor

Answer 3

Allow the coil to rotate continuously and in one direction

Question 4

What is the function of carbon brush

Answer 4

To allow flow of current in the circuit

Question 5

Define electromagnetic induction. What rule is related?

Answer 5

The production of induced current when magnetic flux is cut // there is relative motion btween conductor and magnet.
Fleming’s RIGHT hand rule

Question 6

Define Faraday ‘s law

Answer 6

The magnitude of induced current produced is directly proportional to the rate of cutting of magnetic flux

Question 7

Explain the working principle of a transformer.

Answer 7

1. When AC power supply is turned on, current flows through primary coil to produce electromagnet.
2. Soft iron core is magnetised.
3. Magnitude and direction of current is always changing.
4. Secondary coil is cut by changing magnetic flux.
5. Induced voltage is produced.

Question 8

How to prevent hysteresis

Answer 8

Use soft iron core which can Magnetize and demagnetize easily.

Question 9

What is magnetic field

Answer 9

The region around a Magnet which experiences a Magnetic force.