1. Show that the thermal resistance offered by a spherical wall of uniform k is given by 2. What do you mean by critical radius of insulation? Show that it is given by , where k i is the thermal...

1. Show that the thermal resistance offered by a spherical wall of uniform k is given by

2. What do you mean by critical radius of insulation? Show that it is given by
, where k_i
is the thermal conductivity of insulation and
is the heat transfer coefficient.