Four spheres A, B, C and D of different metals but of same radius and same surface finish are kept at same temperature. The ratio of their unit area at a mean distance 'b' from the sun, densities and specific heats are 2: 3: 5: 1 and solar constant Sand is given by 3 : 6: 2 : 4. Which sphere will show the fastest rate of cooling (initially) (1) A(2) B(3) C(4) D

Four spheres A, B, C and D of different metals but of same radius and

1.	Four spheres A, B, C and D of different metals but of same radius and same surface finish are kept at same temperature. The ratio of their unit area at a mean distance 'b' from the sun, densities and specific heats are 2: 3: 5: 1 and solar constant Sand is given by 3 : 6: 2 : 4. Which sphere will show the fastest rate of cooling (initially) (1) A(2) B(3) C(4) D
Answer» Solution :Since, radius or VOLUME of all the four spheres are equal, the ratio of their masses will be 2 : 3 : 5 : 1. Heat capacity= (mass) (specific heat) `therefore`Ratio of heat capacities will be 6: 18 : 10 : 4. The sphere having the minimum heat capacity will show the fas test rate of cooling. `therefore ` CORRECT option is (4)