Question

# A spherical body of radius b=4π m has a concentric cavity of radius a=2π m as shown. Thermal conductivity of the material is 100 W/m∘C. Find the thermal resistance between inner and outer surface.

A
6.25×104C/W
B
1.25×104C/W
C
6.5×104C/W
D
3.75×104C/W

Solution

## The correct option is A 6.25×10−4∘C/WGiven, Outer radius of spherical body (b)=4π m Inner radius of spherical body (a)=2π m  Thermal conductivity of material (k)=100 W/m∘C Then, thermal resistance (R)=14πk(1a−1b) =14π×100(π2−π4)   =11600=  6.25×10−4∘C/W

Suggest corrections