Heat is flowing through a conductor of length \(l\) from \(x=0\) to \(x=l\). If its thermal resistance per unit length is uniform, which of the subsequent graphs is accurate?
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The pressure applied from all directions on a cube is P. The volume elasticity of the cube is β and the coefficient of volume expansion is α. How much should its temperature be raised to maintain the original volume?
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The plots of intensity versus wavelength for three black bodies at temperatures , and respectively are as shown. Their temperatures are such that:
1. | \(\mathrm{T}_1>\mathrm{T}_2>\mathrm{T}_3 \) | 2. | \(\mathrm{T}_1>\mathrm{T}_3>\mathrm{T}_2 \) |
3. | \(\mathrm{T}_2>\mathrm{T}_3>\mathrm{T}_1 \) | 4. | \(\mathrm{T}_3>\mathrm{T}_2>\mathrm{T}_1\) |
The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity K and 2K and thickness x and 4x, respectively are and ( > ). The rate of heat transfer through the slab, in a steady state is , with f which equals to:
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A wall is made up of two layers, A and B. The thickness of the two layers is the same, but the materials are different. The thermal conductivity of A is double that of B. If in thermal equilibrium, the temperature difference between the two ends is \(36^{\circ}\mathrm{C}\)hen the difference in temperature between the two surfaces of A will be:
1. \(6^{\circ}\mathrm{C}\)
2. \(12^{\circ}\mathrm{C}\)
3. \(18^{\circ}\mathrm{C}\)
4. \(24^{\circ}\mathrm{C}\)
Two rods (one semi-circular and the other straight) of the same material and of the same cross-sectional area are joined as shown in the figure. Points \(A\) and \(B\) are maintained at different temperatures. The ratio of the heat transferred through a cross-section of a semi-circular rod to the heat transferred through a
cross-section of a straight rod at any given point in time will be:
1. \(2:\pi\)
2. \(1:2\)
3. \(\pi:2\)
4. \(3:2\)
The temperature of a body falls from \(50^{\circ}\mathrm{C}\) to \(40^{\circ}\mathrm{C}\) in 10 minutes. If the temperature of the surroundings is \(20^{\circ}\mathrm{C}\)hen the temperature of the body after another 10 minutes will be:
1. \(36.6^{\circ}\mathrm{C}\)
2. \(33.3^{\circ}\mathrm{C}\)
3. \(35^{\circ}\mathrm{C}\)
4. \(30^{\circ}\mathrm{C}\)
Steam at \(100^{\circ}\mathrm{C}\) is injected into 20 g of \(10^{\circ}\mathrm{C}\) water. When water acquires a temperature of \(80^{\circ}\mathrm{C}\), the mass of water present will be: (Take specific heat of water =1 cal g-1 \(^\circ\)C-1 and latent heat of steam = 540 cal g-1)
1. | 24 g | 2. | 31.5g |
3. | 42.5 g | 4. | 22.5 g |
The value of the coefficient of volume expansion of glycerin is \(5\times10^{-4}\) K-1. The fractional change in the density of glycerin for a temperature increase of \(40^\circ \mathrm{C}\) will be:
1. | \(0.015\) | 2. | \(0.020\) |
3. | \(0.025\) | 4. | \(0.010\) |
Two identical bodies are made of a material whose heat capacity increases with temperature. One of these is at \(100^{\circ} \mathrm{C}\), while the other one is at \(0^{\circ} \mathrm{C}\). If the two bodies are brought into contact, then assuming no heat loss, the final common temperature will be:
1. | \(50^{\circ} \mathrm{C}\) |
2. | more than \(50^{\circ} \mathrm{C}\) |
3. | less than \(50^{\circ} \mathrm{C}\) but greater than \(0^{\circ} \mathrm{C}\) |
4. | \(0^{\circ} \mathrm{C}\) |