A small notebook computer has a power rating of 40 W - Edexcel - GCSE Physics - Question 4 - 2012 - Paper 1

The power rating of the computer is given as 40 W. Power (P) is defined as the rate of energy transfer per unit time. Mathematically, this is expressed as:

$P = \frac{E}{t}$

where:

• $P$ is the power in watts (W)
• $E$ is the energy in joules (J)
• $t$ is the time in seconds (s)

Since we want to find out how much energy is supplied each second, we set $t = 1$ s. Therefore, the energy supplied is:

$E = P \times t = 40 \text{ W} \times 1 ext{ s} = 40 ext{ J}$

Thus, the correct answer is C 40 J.