
An electric kettle takes when connected to a circuit of potential difference.
(ii) Find the time required to melt and boil away one kilogram of ice at assuming a loss of generated heat by per cent due to conduction, radiation etc.,

Important Questions on Thermal Effect and Chemical Effect of Current
(iii) Also calculate the cost of electrical energy consumed during the time if the cost of one kilowatt-hour of energy is paise only. Given latent heat of vapourisation of water at is .

(i) Find the time in which the wire will start melting. The change of resistance with temperature of the wire may be neglected.
Given, for copper density , sp. heat melting point resistivity .

(ii) What will this time be if the length of the wire is doubled.
Given, for copper density , sp. heat melting point resistivity .




An electric bulb when connected across a power supply of , consumes a power .
If the supply drops to , then what is the power consumed?
If the supply is suddenly increased to , then what is the power consumed?

In the circuit shown in Fig. the resistance develops due to the current flowing through it. Calculate the heat developed per second in the resistance.
