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Statement-1: When the temperature of a b...

Statement-1: When the temperature of a black body is doubled from` t^(@)C` to `2t^(@)C`, the radiant power becomes 16 times.
Statement-2: The radiant power of a body is proportional to fourth power of absolute temperature.

A

Statement-1 is true, statement-2 is true, statement-2 is a correct explanation for statement-1

B

Statement-1 is true, statement-2 is true, statement-2 is not a correct explanation for statement-1

C

Statement-1 is true, statement-2 is false

D

Statement-1 is false, statement-2 is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze both statements regarding the radiant power of a black body and the relationship between temperature and radiant power. ### Step-by-step Solution: 1. **Understanding Statement 2**: - The radiant power \( P \) of a black body is given by the Stefan-Boltzmann Law, which states that \( P \propto T^4 \), where \( T \) is the absolute temperature in Kelvin. - This means that if the temperature of a black body increases, the radiant power increases with the fourth power of the temperature. **Hint**: Remember that the relationship between temperature and radiant power is exponential, specifically to the fourth power. 2. **Converting Celsius to Kelvin**: - The temperature in Celsius must be converted to Kelvin for the calculations. The conversion formula is: \[ T(K) = T(°C) + 273.15 \] - If we denote the initial temperature as \( t \) degrees Celsius, the absolute temperature \( T_1 \) in Kelvin is: \[ T_1 = t + 273.15 \] - When the temperature is doubled, the new temperature \( T_2 \) in Celsius is \( 2t \) degrees Celsius, which converts to: \[ T_2 = 2t + 273.15 \] **Hint**: Always convert Celsius to Kelvin before using the temperature in any physical equations. 3. **Comparing the Temperatures**: - To find out how the radiant power changes, we need to compare \( T_1 \) and \( T_2 \): \[ T_2 = 2t + 273.15 \] \[ T_1 = t + 273.15 \] - The ratio of the temperatures is: \[ \frac{T_2}{T_1} = \frac{2t + 273.15}{t + 273.15} \] - This ratio is not equal to 2, hence \( T_2 \) is not simply double \( T_1 \). **Hint**: Use the ratio of temperatures to understand how the power changes, rather than assuming a direct doubling. 4. **Calculating the Radiant Power**: - Since the radiant power is proportional to the fourth power of the absolute temperature, we can express the change in power as: \[ \frac{P_2}{P_1} = \left( \frac{T_2}{T_1} \right)^4 \] - Since \( T_2 \) is not exactly double \( T_1 \), we cannot conclude that \( P_2 \) is 16 times \( P_1 \). **Hint**: Remember that the relationship is based on the fourth power of the temperature ratio. 5. **Conclusion**: - Statement 1 is false because the radiant power does not become 16 times when the temperature in Celsius is doubled. - Statement 2 is true as it correctly states the relationship between radiant power and absolute temperature. ### Final Answer: - **Statement 1**: False - **Statement 2**: True
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