A 2000W electric heater is used to heat a metal object of mass 5kg initially at 10oC. If a temperature rise of 30oC is obtained after 10min, the heat capacity of the material is
A
6.0 x 104JoC-1
B
4.0 x 104JoC-1
C
1.2 x 104JoC-1
D
8.0 x 103JoC-1
Verified Correct Answer: B.
Physical Principles & Numerical Solution
mc\DeltaT = Pt → 5 x c x 30 = 2000 x 10 x 60
c = \(\frac{1200000}{150}\)
c = 8000 = 8.0 x \(10^3J/kgºC^{-1}\)
But, Heat capacity C = mass x specific heat capacity
C = 5 x 8000 = 40000 = 4 x (10^4JºC^{-1}\)
(OR) C = \(\frac{2000* 10* 60*}{30}\) = 40,000JºC\(^{-1}\)
Source: Myschool Past Questions Archive (Record #12285)