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

1.	A lead piece of mass 25gm 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) = 25gm = 0.025Kg , Amount of heat given out = 1200 calories Amount of heat energy given out (DQ) `= 1200 XX 4.2J [therefore W = JH]` The fall in temperature `(dT) = (90 - 10)^(0)C =80^(0)C = 80K` (i) Specific heat `S = 1/m (dQ)/(dT)=1/(0.025)xx(1200xx4.2)/(80)=(5040)/2 = 2520 J Kg^(-1)K^(-1)` (II) Thermal capacity `= ms = 0.025 xx 2520 = 633 K^(-1)` (iii) WATER equivalent `=ms= 63"Kg"^2`.