- 1(current)
Q. No.| Assertion (A): |
Houses made of concrete roofs overlaid with foam keep the room hotter during |
| Reason (R): |
The layer of foam insulation prohibits heat transfer, as it contains air pockets. |
In the light of the above statements, choose the correct answer from the options given below:
| 1. | (A) is True but (R) is False. |
| 2. | (A) is False but (R) is True. |
| 3. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 4. | Both (A) and (R) are True and (R) is the correct explanation of (R). |
1. \(12^\circ \text{C}\)
2. \(50^\circ \text{C}\)
3. \(73^\circ \text{C}\)
4. \(88.5^\circ \text{C}\)
The quantities of heat required to raise the temperature of two solid copper spheres of radii \(r_1\) and \(r_2\) \((r_1=1.5~r_2)\) through \(1~\text{K}\) are in the ratio:
| 1. | \(\dfrac{9}{4}\) | 2. | \(\dfrac{3}{2}\) |
| 3. | \(\dfrac{5}{3}\) | 4. | \(\dfrac{27}{8}\) |
A deep rectangular pond of surface area \(A\), containing water (density = \(\rho,\) specific heat capacity = \(s\)), is located in a region where the outside air temperature is at a steady value of \(-26^{\circ}\text{C}\). The thickness of the ice layer in this pond at a certain instant is \(x\). Taking the thermal conductivity of ice as \(k\), and its specific latent heat of fusion as \(L\), the rate of increase of the thickness of the ice layer, at this instant, would be given by:
1. \(\dfrac{26k}{x\rho L-4s}\)
2. \(\dfrac{26k}{x^2\rho L}\)
3. \(\dfrac{26k}{x\rho L}\)
4. \(\dfrac{26k}{x\rho L+4s}\)
- 1(current)
Q. No.
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