What does power input mean? Tick (✓) one box - AQA - GCSE Physics - Question 9 - 2019 - Paper 1

The equation is: $P = V imes I$ where P is power, V is potential difference, and I is current.

Given the power input (P) is 40 W and the potential difference (V) is 230 V, we can rearrange the formula to find the current (I): $I = \frac{P}{V} = \frac{40 \text{ W}}{230 \text{ V}} \approx 0.17 \text{ A}$

The equation is: $\text{Efficiency} = \frac{\text{Useful Power Output}}{\text{Total Power Input}}$

Given the useful power output is 0.30 W and the total power input is 9.0 W: $ext{Useful Power Output} = 0.30 \text{ W} \to X = 0.30 \text{ W} \times 9.0$ This results in: $X = 2.7 \text{ W}$

Labeling light bulbs with their visible light emission rate helps consumers understand how effectively the bulb converts electricity into visible light, allowing them to choose bulbs that provide the desired brightness while considering energy efficiency.