Question

A Bunsen burner raises the temperature of 500g of water from 10°C to 100°C in 5 minutes. What heat is supplied per second?

Answer 1

m = mass of water = 500 g, θ₁ = Initial temperature = 10 °C

c = Specific heat capacity of water = 4.2 J/g °C, θ₂ = Final temperature = 100 °C

Let Q be heat supplied by Bunsen burner = Q

Heat lost by Bursen burner = Heat gained by water   ...(Law of calorimetry)

Q = mc(θ₂ - θ₁) 

Q = 500 × 4.2 × (100 - 10)

Q = 500 × 4.2 × 90

Q = 189000 J

Heat supplied by burner per second Q = `"Total heat"/"time" = 189000/"300s"`J

= 630 J/s

Heat supplied per second is 630 J/s.