A black walled metal container of negligible heat capacity is filled with water. The container has sides of length 10cm. It is placed in an evacuated chamber at `27^(@)C.` How long will it take for the temperature of water to change from `30^(@)C to 29^(@)C.`

Explanation

To solve the problem of how long it will take for the temperature of water in a black walled metal container to change from 30°C to 29°C, we will use Newton's law of cooling. Here’s a step-by-step solution:

### Step 1: Understand the parameters
We have a black walled metal container with negligible heat capacity filled with water. The container's sides are 10 cm long, and it is placed in an evacuated chamber at 27°C. We need to find the time it takes for the water's temperature to drop from 30°C to 29°C.

### Step 2: Determine the average temperature
The average temperature (T_avg) during the cooling process can be calculated as:
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