KCET · Physics · Thermal Properties of Matter
Four rods with different radii \( r \) and length \( l \) are used to connect two heat reservoirs at different
temperature. Which one will conduct most heat?
- A \( r=1 \mathrm{~cm}, l=1 \mathrm{~m} \)
- B \( r=1 \mathrm{~cm}, l=\frac{1}{2} m \)
- C \( r=2 \mathrm{~cm}, l=2 \mathrm{~m} \)
- D \( r=2 \mathrm{~cm}, l=\frac{1}{2} m \)
Answer & Solution
Correct Answer
(D) \( r=2 \mathrm{~cm}, l=\frac{1}{2} m \)
Step-by-step Solution
Detailed explanation
The amount of heat conducted depends on radii r andlength I as
\( Q \propto \frac{r^{2}}{l} \)
Thus, rod will conduct maximum for maximum r value and minimum I value,
Therefore, \( r=2 \mathrm{~cm} \) and \( l=\frac{1}{2} m \)
\( Q \propto \frac{r^{2}}{l} \)
Thus, rod will conduct maximum for maximum r value and minimum I value,
Therefore, \( r=2 \mathrm{~cm} \) and \( l=\frac{1}{2} m \)
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