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A refrigerator works between 4^(@)C and ...

A refrigerator works between `4^(@)C` and `30^(@)C`. It is required to remove `600 calories` of heat every second in order to keep the temperature of the refrigerator space constant.The power required is (Take `1calorie= 4.2 J`)

A

`23.65W`

B

`236.5W`

C

`2365W`

D

`2.365W`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to calculate the power required for the refrigerator to remove heat while working between two temperature limits. Here’s a step-by-step solution: ### Step 1: Convert temperatures to Kelvin The temperatures given in Celsius need to be converted to Kelvin: - \( T_1 = 30^\circ C = 30 + 273 = 303 \, K \) - \( T_2 = 4^\circ C = 4 + 273 = 277 \, K \) **Hint:** Remember that to convert Celsius to Kelvin, you add 273. ### Step 2: Convert heat removal to Joules The heat removal rate is given as \( 600 \, \text{calories/second} \). We need to convert this to Joules using the conversion factor \( 1 \, \text{calorie} = 4.2 \, \text{J} \): - \( Q_2 = 600 \, \text{calories/second} \times 4.2 \, \text{J/calorie} = 2520 \, \text{J/s} \) **Hint:** Use the conversion factor to change calories to Joules. ### Step 3: Calculate the Coefficient of Performance (COP) The Coefficient of Performance (COP) for a refrigerator is given by the formula: \[ \beta = \frac{Q_2}{W} = \frac{T_2}{T_1 - T_2} \] We can rearrange this to find the work done \( W \): \[ W = \frac{Q_2 \cdot (T_1 - T_2)}{T_2} \] **Hint:** The COP relates the heat removed and the work done; rearranging the formula helps to isolate \( W \). ### Step 4: Substitute values into the equation Now, substitute the values we have: - \( Q_2 = 2520 \, \text{J/s} \) - \( T_1 = 303 \, K \) - \( T_2 = 277 \, K \) Calculating \( T_1 - T_2 \): \[ T_1 - T_2 = 303 - 277 = 26 \, K \] Now substituting into the equation for \( W \): \[ W = \frac{2520 \, \text{J/s} \cdot 26 \, K}{277 \, K} \] ### Step 5: Calculate \( W \) Now perform the calculation: \[ W = \frac{65520 \, \text{J/s}}{277} \approx 236.5 \, \text{W} \] **Hint:** When performing the division, ensure you keep track of significant figures. ### Step 6: Conclusion The power required for the refrigerator to remove 600 calories of heat every second is approximately \( 236.5 \, \text{W} \). **Final Answer:** The power required is \( 236.5 \, \text{W} \). ---

To solve the problem, we need to calculate the power required for the refrigerator to remove heat while working between two temperature limits. Here’s a step-by-step solution: ### Step 1: Convert temperatures to Kelvin The temperatures given in Celsius need to be converted to Kelvin: - \( T_1 = 30^\circ C = 30 + 273 = 303 \, K \) - \( T_2 = 4^\circ C = 4 + 273 = 277 \, K \) **Hint:** Remember that to convert Celsius to Kelvin, you add 273. ...
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