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A metal cylinder of mass `0.5` kg is heated electrically by a 12 W heater in a room at `15^(@)` C. The cylinder temperature rises uniformly to `25^(@)` C in 5 min and finally becomes constant at `45^(@)` C Assuming that the rate of heat losss is proportional to the excees temperature over the surroundings,A. the rate of loss of heat of the cylinder to surrounding at `20^(@)` C is 2WB. the rate of loss of heat of the cylinder to surrounding at `45^(@)` C is 12WC. the rate of loss of heat of the cylinder to surrounding at `20^(@)` C is 5WD. the rate of loss of heat of the cylinder to surrounding at `45^(@)` C is 30W. |
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Answer» Correct Answer - A::B Rate of heat loss `((dQ)/(dt))_(loss)=k(theta-theta_(0))` At `45^(@)` C Rate of heat loss = Rate of heat supplied =12W `k(45-15)=12` `Rightarrow k=2//5 W//^(@)C` `((dQ)/(dt))_(loss)=k(20-15)=2W` |
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