A 50W electric heater is used to heat a metal block of mass 5kg. If in 10 minutes a temperature rise of 12°C is achieved; the specific heat capacity of the metal is?

A. 400 J kg^-1K^-1
B. 500 J kg^-1K^-1
C. 390 J kg^-1K^-1
D. 130 J kg^-1K^-1

Correct Answer:

Option B – 500 J kg^-1K^-1

Explanation

Heat supplied by the heater in 10 mins
= power x time
= 50 x (10 x 60)
= 30000 J
This heat is equal = MCΔt
= 5 x c x 12
= 60cJ
= 60C = 30,000
C = 30,000/60
C = 500 J kg^-1K^-1