An electric kettle with resistance 22 Ω and a microwave oven with resistance 44 Ω are connected in parallel and the combination is connected across a source of voltage 230 V as shown in the diagram - NSC Technical Sciences - Question 9 - 2022 - Paper 1

The power ( P) in an electrical circuit is calculated using the formula:

$P = \frac{V^2}{R}$

where V is the voltage and R is the resistance.

For the electric kettle, substituting the values:

$P = \frac{230^2}{22} = \frac{52900}{22} \approx 2404.55 W$

The heat produced ( W) can be calculated with the formula:

$W = P \cdot t$

where P is the power and t is the time in seconds.

For 2 minutes:

$t = 2 \times 60 = 120 \text{ seconds}$

Substituting the values:

$W = 2404.55 \cdot 120 \approx 288546 W \cdot s = 288546 J$