- Heat Transfer - Section 1
- Heat Transfer - Section 2
- Heat Transfer - Section 3
- Heat Transfer - Section 4
- Heat Transfer - Section 5
- Heat Transfer - Section 6
- Heat Transfer - Section 7
- Heat Transfer - Section 8
- Heat Transfer - Section 9
- Heat Transfer - Section 10
- Heat Transfer - Section 11


Heat Transfer - Engineering
Q1: In Joule's experiment, an insulated container contains 20 kg of water initially at 25°C. It is stirred by an agitator, which is made to turn by a slowly falling body weighing 40 kg through a height of 4 m. The process is repeated 500 times. The acceleration due to gravity is 9.8 ms-2. Neglecting the heat capacity of agitator, the temperature of water (in °C) isA 40.5
B 34.4
C 26.8
D 25
ANS:B - 34.4 In Joule's experiment, mechanical work is done on the water by the agitator, which transfers energy into the water and increases its temperature. The increase in temperature can be calculated using the principle of conservation of energy. The work done by the falling body in each cycle is given by work=force×distancework=force×distance. The force applied by the falling body is the gravitational force acting on it, given by force=mass×acceleration due to gravityforce=mass×acceleration due to gravity. Therefore, the work done in each cycle is work=mass×acceleration due to gravity×distancework=mass×acceleration due to gravity×distance. Given:
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