JAMB - Physics (2003 - No. 21)

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

6.0 x 10⁴J^oC^-1

4.0 x 10⁴J^oC^-1

1.2 x 10⁴J^oC^-1

8.0 x 10³J^oC^-1

Explanation

mcΔT = 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\(^{-1}\)

JAMB - Physics (2003 - No. 21)

Explanation

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