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A 2 kW, 40 litres water heater is switched on for 20 minutes. The heat capacity cp for water is 4.2 kJ/kgK. Assuming all the electrical energy has gone into heating the water, increase of the water temperature in degree centigrade is
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- 2.7
- 4.0
- 14.3
- 25.25
- 2.7
Correct Option: C
Energy given by water = Energy taken by heater P.t = mcp ∆T = 2 × 20 × 60 = 40 × 4.2 × ∆t ∆t = 14.3 °C
