Question

12.) 200 g of ice at 0°C converts into water at 0°C in
1 minute when heat is supplied to it at a constant
rate. In how much time 200 g of water at 0°C
will change to 20°C ? Take specific latent heat of ice
= 336 J/g​

Answer 1

Total heat required for complete change in phase = m*L

where, m=mass, L= Specific Latent Heat

∴Q=200 * 336 = 6720J

Power= Q/t = 6720 / 60 = 112 W

Time required for  20° rise in temp = P / (m * c * ΔT)

= 112 / (200 * 4.2 * 20) = 16800 / 112 = 150 seconds = 2min 30 sec