Question

Two Solid spheres A and B made of same material but of Different size Contains Heat energy 100J and 20J respectively. If they brought in contact what will be the direction of heat transfer?​

Answer 1

Heat loss, as per stephan boltzman law is given by the relation:

q

′

=eσAT

4

q

′

=eσT

4

(4πr

2

)

Also,

3

4

πr

3

=

ρ

m

r=km

1/3

Hence,

q

2

′

q

1

′

=

r

2

2

r

1

2

=(

m

2

m

1

)

2/3

=4

2/3

=2

4/3

Also, rate of cooling is given by

R=

mc

q

′

=

m

Aq

′

where A is some constant.

Hence,

R

2

R

1

=(

m

1

m

2

)

1/3

=2

−2/3