2 (a) Figure 4 shows the inside of a mains plug - Edexcel - GCSE Physics - Question 2 - 2020 - Paper 1

The meter on the battery charger is A an ammeter.

An ammeter is specifically designed to measure the current flowing in a circuit.

To calculate the charge flowing to the battery, we will use the formula:

$$ext{charge} = ext{current} imes ext{time}$$

Given:

• Current = 2.5 A
• Time = 8 minutes = 8 imes 60 = 480 seconds

Calculating:

$$ext{charge} = 2.5 ext{ A} imes 480 ext{ s} = 1200 ext{ C}$$

Thus, the total charge flowing to the battery is 1200 C.

Using the given formula:

$$ext{primary current} = \frac{\text{secondary voltage} \times \text{secondary current}}{\text{primary voltage}}$$

Substituting the known values:

• Secondary voltage = 15 V
• Secondary current = 3.1 A
• Primary voltage = 230 V

Thus:

$$ext{primary current} = \frac{15 imes 3.1}{230} = 0.202173913 ext{ A}$$

Rounding to 0.20 A.