#### Question

Two copper spheres of radii 6 cm and 12 cm respectively are suspended in an evacuated enclosure. Each of them are at a temperature 15°C above the surroundings. The ratio of their rate of loss of heat is.................

- 2:1
- 1:4
- 1:8
- 8:1

#### Solution

(b) 1:4

r_{1} = 6 cm

r_{2} = 12 cm

T_{1} = T_{2} = 15°C

Ratio of loss of heat is

`R_1/R_2=A_1/A_2xxT_1^4/T_2^4`

`R_1/R_2=(4pir_1^2)/(4pir_2^2)=6^2/12^2=1/4`

Is there an error in this question or solution?

Solution Two Copper Spheres of Radii 6 Cm and 12 Cm Respectively Are Suspended in an Evacuated Enclosure. Each of Them Are at a Temperature 15°C Above the Surroundings. the Ratio of Their Rate of Loss of Heat is Concept: Temperature and Heat.