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Thermal Properties Of Matter

Question

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Two rods of same material have same length and area. The heat ΔQ flows through them for 12 minutes when they are joint side by side. If now both the rods are joined in parallel, then the same amount of heat ΔQ will flow in :

24 min

3 min

12 min

6 min

Solution

3 min

When rods are joined in series then heat flow

$∆ Q = \frac{A (T_{1} - T_{2}) t_{1}}{\frac{l_{1}}{K_{1}} + \frac{l_{1}}{K_{2}}} = \frac{A (T_{1} + T_{2}) t_{1}}{\frac{1}{K_{1}} + \frac{1}{K_{2}}} ∆ Q = \frac{A (T_{1} - T_{2}) t_{1}}{l_{1}} \frac{K}{2}$

When rods are joined in parallel

$∆ Q_{2} = (K_{1} A - K_{2} A) \frac{(T_{1} - T_{2}) t_{2}}{l} ∆ Q_{2} = \frac{2 K A (T_{1} - T_{2}) t_{2}}{l} ∵ ∆ Q_{1} = ∆ Q_{2} (given)$

$∴ t_{2} = \frac{t_{1}}{4} = \frac{12}{4} = 3 \min$

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Thermal Properties Of Matter

Two rods of same material have same length and area. The heat ΔQ flows through them for 12 minutes when they are joint side by side. If now both the rods are joined in parallel, then the same amount of heat ΔQ will flow in :

24 min

3 min

12 min

6 min

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For Daily Free Study Material Join wiredfaculty

Thermal Properties Of Matter

Two rods of same material have same length and area. The heat ΔQ flows through them for 12 minutes when they are joint side by side. If now both the rods are joined in parallel, then the same amount of heat ΔQ will flow in : 24 min 3 min 12 min 6 min

Some More Questions From Thermal Properties of Matter Chapter

If Cp and Cv denote the specific heats of nitrogen per unit mass at constant pressure and constant volume respectively, then

A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Two rods of same material have same length and area. The heat ΔQ flows through them for 12 minutes when they are joint side by side. If now both the rods are joined in parallel, then the same amount of heat ΔQ will flow in :

24 min

3 min

12 min

6 min

If C_p and Cv denote the specific heats of nitrogen per unit mass at constant pressure and constant volume respectively, then