(i) Definition and expression:
Electric power is the rate at which electric energy is consumed (or dissipated) in a circuit.
$$P = VI = I^2R = \frac{V^2}{R}$$
In terms of V and R:
$$\boxed{P = \frac{V^2}{R}}$$
(ii) Given: V = 220 V, Energy consumed = 11 units = 11 kWh, time = 5 h
(a) Power rating:
$$P = \frac{\text{Energy}}{\text{time}} = \frac{11 \text{ kWh}}{5 \text{ h}} = 2.2 \text{ kW} = \mathbf{2200 \text{ W}}$$
(b) Current drawn:
$$I = \frac{P}{V} = \frac{2200 \text{ W}}{220 \text{ V}} = \mathbf{10 \text{ A}}$$
(c) Resistance of the oven:
$$R = \frac{V}{I} = \frac{220 \text{ V}}{10 \text{ A}} = \mathbf{22 \text{ Ω}}$$
Source: Chapter 11 (Electricity), Section 11.8 Electric Power
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