A metallic cylindrical vessel whose inner and outer radii are r_(1) and r_(2) is filled with ice at 0^(0)C. The mass of the ice in the cylinder is m. Circular portions of the cylinder is sealed with completely adiabatic walls. The vessel is kept in air. Temperature of the air is 50^(0)C. How long will it take for the ice to melt completely. Thermal conductivity of the cylinder is k and its length is l. Latent heat of fusion is L.

A metallic cylindrical vessel whose inner and outer radii are r_(1) an

1.	A metallic cylindrical vessel whose inner and outer radii are r_(1) and r_(2) is filled with ice at 0^(0)C. The mass of the ice in the cylinder is m. Circular portions of the cylinder is sealed with completely adiabatic walls. The vessel is kept in air. Temperature of the air is 50^(0)C. How long will it take for the ice to melt completely. Thermal conductivity of the cylinder is k and its length is l. Latent heat of fusion is L.
Answer» `(mLln(r_(2)//r_(1)))/(100pi kl)` `(3mLln(r_(1)//r_(2)))/(400kl)` `(mLln(3r_(1)//r_(2)))/(4pi kl)` `(3mLln(r_(1)//r_(2)))/(PI k L)` ANSWER :A