Ice has formed on a shallow pond, and a steady state has been reached, with the air above the ice at `-5.0^(@)C` and the bottom of the pond at `40^(@)C`. If the total depth of ice + water is `1.4 m`, (Assume that the thermal conductivities of ice and water are `0.40` and `0.12 cal//m C^(@)s`, respectively.)
The thickness of ice layer is