Figure 9 shows a lamp connected to a d.c - Edexcel - GCSE Physics Combined Science - Question 5 - 2022 - Paper 1

To calculate the power supplied to the lamp, we can use the formula:
$Power = V \times I$
Substituting the values we get:
$Power = 4.5 \, V \times 0.30 \, A = 1.35 \, W$
Thus, the power supplied to the lamp is 1.35 W.

The brightness of a lamp is dependent on the power it receives. In Figure 9, the lamp receives power from a single power supply at 1.35 W. In Figure 10, with two identical lamps connected in parallel to the same power supply, each lamp will share the available power equally.
Therefore, each lamp in Figure 10 receives a lower power (0.675 W each), making them dimmer than the single lamp in Figure 9.

To measure the resistance of 50 cm of resistance wire, the student should connect a low voltage power supply, a switch, an ammeter, a voltmeter, and the resistance wire in series.
The voltmeter should be connected across the 50 cm of resistance wire to measure the voltage across it, while the ammeter measures the current flowing through the circuit.

Direct current (d.c.) is the flow of electric charge in one direction, maintaining a constant voltage over time, such as what is produced by batteries. In contrast, alternating current (a.c.) is the flow of electric charge that periodically reverses direction, resulting in a voltage that varies sinusoidally over time, which is commonly found in household electricity supply.