When a potential difference, V is applied across the ends of a resistor of resistance, R a Current, l passes through the resistor. The heat generated in the resistor in time, t is given by the expression
What amount of current would pass through a 10 Ω coil if it takes 21s for the coil to just melt a lump of ice of mass 10g at 0oC if there are no heat losses? (Latent heat of fusion of ice = 336 Jg\(^{-1}\)).
How long does it take a 750 W heater operating at full rating to raise the temperature of 1 kg of water from 40oC to 70oC? (Take the specific heat capacity of water as 4200 J kg-1 K-1 and neglect heat losses).
