Question

A electrical appliance is rated 2000 W − 200 V. This appliance is connected to 200 V mains. Calculate:

1. Current drawn by the appliance.
2. Resistance offered by the appliance.
3. Electric energy consumed by the appliance in 10 hours.
4. Cost of the electric energy consumed at ₹ 7.50 per kWh.

Answer 1

Given: $$P = 2000\ \text{W}, V = 200\ \text{V}, t = 10\ \text{h}$$

(i) Current drawn by the appliance:

$$I = \frac{P}{V}$$

$$= \frac{2000}{200}$$

$$= 10\ \text{A}$$

(ii) Resistance offered by the appliance:

$$R = \frac{V}{I}$$

$$= \frac{200}{10}$$

$$= 20\ \Omega$$

(iii) Electric energy consumed in 10 hours:

$$E = Pt$$

$$= 2000\ \text{W} \times 10\ \text{h}$$

$$= 20000\ \text{Wh}$$

$$= 20\ \text{kWh}$$

(iv) Cost of electric energy consumed:

Total Cost = Energy consumed (kWh) × Rate per kWh

$$= 20 \times 7.50$$

= ₹ 150