In List-I, certain situations are depicted where steam at 100°C is used to melt ice at 0°C by means of a conducting body which is insulated to prevent heat losses to surrounding. Match the numerical v

Question

In List-I, certain situations are depicted where steam at 100°C is used to melt ice at 0°C by means of a conducting body which is insulated to prevent heat losses to surrounding. Match the numerical value of question asked in each entry to the corresponding entry in List-II. Symbols have usual meaning.

List-I	List-II
(I) Find temperature of interface of two rods in °C.	(P) 10
(II) Find total rate of heat transfer through the two rods in SI units.	(Q) 20
(III) Find thermal resistance in SI units.	(R) 30
(IV) Find temperature gradients in SI units.	(S) 40
	(T) 50

TestHub · Accepted Answer

(I) Series rods: heat current is the same through both. $\frac{10 \times A}{2} (100 - T) = \frac{20 \times A}{1} (T - 0) \Rightarrow 100 - T = 4 T \Rightarrow T = 20$ → I → Q (20).

(II) $\frac{10 \times A ( 100 )}{1} + \frac{20 \times A ( 100 )}{1} = 3000 \times 100 \times 1 0^{- 4} = 30 W$ → II → R (30).

(III) Thermal resistance of hollow sphere: $R_{T h} = \frac{( 0.2 - 0.1 )}{4 π \times 0.2 \times 0.1} \times 32 π = 40$ SI units → III → S (40).

(IV) Temperature gradient in the hollow cylinder: $\frac{d t}{d x} = \frac{100 - 0}{10} = 10° C/m$ → IV → P (10).

Hence I → Q; II → R; III → S; IV → P, option (A).

Physics - Heat & Thermo Question with Solution | TestHub

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