Thickness of ice on a lake is 5 cm and the temperature of air is `-20^(@)C` . If the rate of cooling of water inside the lake be 20000 cal `min^(-1)` through each square metre surface , find K for ice .

Explanation

To solve the problem, we need to find the thermal conductivity (K) of ice given the thickness of the ice, the temperature difference, and the rate of heat transfer. Here’s a step-by-step solution:

### Step 1: Convert the thickness of ice from cm to meters
The thickness of the ice is given as 5 cm. We need to convert this to meters for consistency in SI units.

\[ \text{Thickness (L)} = 5 \, \text{cm} = 5 \times 10^{-2} \, \text{m} \]
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