An electric kettle contains a heating coil of resistance and is connected to a mains…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Electric Circuits · Electric Circuits
Problem
An electric kettle contains a heating coil of resistance 44Ω and is connected to a 220V mains supply. The kettle is fitted with a fuse rated at 5A.
(i) Calculate the power developed in the heating coil under normal operation.
(ii) State, with calculations, whether the 5A fuse will operate when the kettle is switched on.
(iii) The kettle is used to heat 1kg of water from 25∘C to its boiling point at 100∘C. Assuming 80% of the electrical energy supplied is absorbed by the water, estimate the time required for the water to reach boiling. \,(Specific heat capacity of water =4.2×103J kg−1∘C−1.)