Question

The temperature of 600 g of cold water rises by 15 degree C when 300 g of hot water at 50 degree C is added to it.what was the initial temperature of cold water?

Answer 1

Heat gained by cold water = Heat loss by hot water

mSΔT = m’SΔT’

m ΔT = m’ ΔT’

600 g × 15 °C = 300 g × ΔT’

ΔT’ = 30 °C

Change in temperature of hot water is 30°C

30°C = 50°C - T ………[∵ Initial Temperature of water was 50°C]

T = 20°C

Final temperature of hot water = Temperature of mixture = 20°C

Given that,

Rise in temperature of cold water = 15°C

20°C - T’ = 15°C

T’ = 5°C

∴ Initial Temperature of cold water is 5°C

Hope it is clear.....!!!!!