Question

An electric appliance is rated at 1000 W, 250V. Calculate:
(i) The electrical energy consumed by the appliance in 12 hour.
(ii) The cost of energy consumed at Rs. 1.20 per kWh.
How long would this appliance take to use 1 kWh energy when operated at 250 V?

Answer 1

Given: P = 1000W, V = 250V, t = 12 hr

(i) Electrical energy consumed = `"Watt"/1000 xx "time" ("in hr.")`

`= 1000/1000 xx 12` = 12 kWh

(ii) Cost = 12 × 1.20 = Rs. 14.40

If it takes t hour to consume 1 kWh electric energy, then:

I = `(1000xx"t")/1000`

or  t = 1 hr.