Why is the metal covering of an electrical appliance earthed?

An electrical appliance is rated as 60 W - 150 V.

(a) What do you understand by this statement?

(b) How much current will flow through the appliance when in use?

Assuming the electric consumption per day to be 12 kWh and the rate of electricity to be Rs 6.25 per unit, find how much money is to be paid in a month of 30 days?

In a premise 5 bulbs each of 100 W, 2 fans each of 60 W, 2 A.Cs each of 1.5 kW are used for 5 h per day. Find:

(a) total power consumed per day,

(b) total power consumed in 30 days,

(c) total electrical energy consumed in 30 days,

(d) the cost of electricity at the rate of Rs 6.25 per unit.