A lead piece of mass 25 g gives out 1200 calories of heat when it is cooled from 90^(@)C to 10^(@)C. What is its i) Specific heat ii) thermal capacity and iii) Water equivalent.

A lead piece of mass 25 g gives out 1200 calories of heat when it is c

1.	A lead piece of mass 25 g gives out 1200 calories of heat when it is cooled from 90^(@)C to 10^(@)C. What is its i) Specific heat ii) thermal capacity and iii) Water equivalent.
Answer» Solution :MASS of lead piece (m) = 25 G = 0.025 kg AMOUNT of heat GIVEN out = 1200 calories Amount of heat energy given out (dQ) = `1200xx4.2J` The fall in temperature (dT) = `(90-10)^(@)C=80^(@)C=80K` (i) Specific heat S = `1/m(dQ)/(dT)=1/0.025xx(1200xx4.2)/80` = `5040/2=2520Jkg^(-1)K^(-1)` (ii) Thermal capacity = MS = `0.025xx2520=63JK^(-1)` (iii) Water equivalent = W = `63/4200kg`