10.1 What phenomenon is illustrated in the diagram above? 10.1.2 If the speed at which the magnet is moved in and out of the coil is increased, a greater deflection of the needle is observed - NSC Technical Sciences - Question 10 - 2021 - Paper 1

When the speed of the magnet's movement is increased, the rate of change in the magnetic flux through the coil also increases. According to Faraday's Law of Electromagnetic Induction, the induced emf is directly proportional to the rate of change of magnetic flux. Therefore, as the rate of change increases due to faster movement, the induced emf and the deflection of the needle also increase.

The type of current induced in the above diagram is Alternating Current.

1. The primary voltage (220 V) is higher than the secondary voltage (24 V), which is characteristic of a step-down transformer.

2. The transformer has more windings in the primary coil than in the secondary coil, resulting in a decrease in voltage from primary to secondary.

To find the number of windings in the primary coil (Np), we can use the transformer equation:

$\frac{V_p}{V_s} = \frac{N_p}{N_s}$

Where:

• $V_p$ = Primary voltage (220 V)
• $V_s$ = Secondary voltage (24 V)
• $N_s$ = Number of windings in the secondary coil (480 windings)

Substituting the values in: $\frac{220}{24} = \frac{N_p}{480}$

Cross-multiplying gives: $N_p = \frac{220 \times 480}{24} = 4400 \text{ windings}$