- 1(current)
Q. No.When the temperature difference between a body and its surroundings is \(20^{\circ}\text{C}\), it loses heat to the surroundings at a rate of \(40\) W. If the temperature difference increases to \(25^{\circ}\text{C}\), the rate of loss of heat is:
1. \(45\) W
2. \(50\) W
3. \(60\) W
4. \(80\) W
1. \(45\) W
2. \(50\) W
3. \(60\) W
4. \(80\) W
Subtopic: Â Newton's Law of Cooling |
 77%
Level 2: 60%+
Hints
A body cools from \(52^\circ \text{C}\) to \(48^\circ \text{C}\) in \(6\) minutes. How much time will the same body take to cool from \(53^\circ \text{C}\) to \(47^\circ \text{C}?\) Assume cooling is linear with time.
1. \(12\) minutes
2. \(9\) minutes
3. \(8\) minutes
4. \(7\) minutes
1. \(12\) minutes
2. \(9\) minutes
3. \(8\) minutes
4. \(7\) minutes
Subtopic: Â Newton's Law of Cooling |
 82%
Level 1: 80%+
Hints
A body loses heat at a rate of \(2~\text{W/min}\) when it is at a temperature of \(40^{\circ}\text C,\) but at a rate of \(1~\text{W/min}\) when its temperature is \(30^{\circ}\text C.\) The temperature of the surroundings is:
1. \(25^{\circ}\text{C}\)
2. \(20^{\circ}\text{C}\)
3. \(10^{\circ}\text C\)
4. \(35^{\circ}\text C\)
1. \(25^{\circ}\text{C}\)
2. \(20^{\circ}\text{C}\)
3. \(10^{\circ}\text C\)
4. \(35^{\circ}\text C\)
Subtopic: Â Newton's Law of Cooling |
 70%
Level 2: 60%+
Hints
- 1(current)
Q. No.
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