A hollow sphere of inner radius R_(1)=0.25m and outer radius R_(2)=0.50 m is placed inside a heat reservoir of temperature T_(0)=1000^(0)C. The hollowsphere contains water at initial temperature 0^(0)C. The thermal conductivity of the material is K=(10^(2))/(4pi)W//m-K. The time required to raise the temperature of water to 100^(0)C.

A hollow sphere of inner radius R_(1)=0.25m and outer radius R_(2)=0.5

1.	A hollow sphere of inner radius R_(1)=0.25m and outer radius R_(2)=0.50 m is placed inside a heat reservoir of temperature T_(0)=1000^(0)C. The hollowsphere contains water at initial temperature 0^(0)C. The thermal conductivity of the material is K=(10^(2))/(4pi)W//m-K. The time required to raise the temperature of water to 100^(0)C.
Answer» 9 min 39 sec 6 min 13 sec 12 min 10 sec 5 min 12 sec Answer :A