Q. No.A ring consisting of two parts, ADB and ACB, of the same heat conductivity k, conducts an amount of heat H. The ADB part is now replaced with another metal, keeping the temperatures constant. The amount of heat carried rises to 2H. What should be the heat conductivity of the new ADB part?
1.
2. 2k
3.
4. 3k
1.
A geyser heats water flowing at a rate of 3.0 litres per minute from \(27^{\circ} \mathrm{C}\) to \(77^{\circ}\mathrm{C}\). If the geyser operates on a gas burner and its heat of combustion is 4
| 1. | 24 g/min | 2. | 12 g/min |
| 3. | 32 g/min | 4. | 16 g/min |
Two taps, one at \(10^{\circ} \mathrm{C}\) and the other at \(100^{\circ} \mathrm{C}\), both supply water. How much hot water must be mixed with the cold water so that we get 20 kg of water at \(35^{\circ} \mathrm{C}\)?
| 1. | 7.2 kg | 2. | 10 kg |
| 3. | 5.6 kg | 4. | 14.4 kg |
When a uniform rod is heated, which of its following properties will increase as a result of it?
1. mass
2. weight
3. center of mass
4. moment of inertia
If the same amount of heat is supplied to two spheres of the same material having the same radius (one is hollow and the other is solid), then:
| 1. | the expansion in hollow is greater than the expansion in solid |
| 2. | the expansion in hollow is the same as that in solid |
| 3. | the expansion in hollow is lesser than in solid |
| 4. | the temperature of both must be the same |
5 g of water at \(30^{\circ} \mathrm{C}\) and 5 g of ice at \(-20^{\circ} \mathrm{C}\) are mixed together in a calorimeter. The water equivalent of the calorimeter is negligible, and the specific heat and latent heat of ice are 0.5 \(\text{cal/g}^{\circ} \mathrm{C}\) and 80 \(\text{cal/g}\), respectively. The final temperature of the mixture is:
| 1. | \(0^{\circ} \mathrm{C}\) | 2. | \(-8^{\circ} \mathrm{C}\) |
| 3. | \(-4^{\circ} \mathrm{C}\) | 4. | \(2^{\circ} \mathrm{C}\) |
Three rods made of the same material, having the same cross-sectional area but different lengths 10 cm, 20 cm and 30 cm are joined as shown. The temperature of the junction will be:-
1. \(10.8^{\circ}\mathrm{C}\)
2. \(14.6^{\circ}\mathrm{C}\)
3. \(16.4^{\circ}\mathrm{C}\)
4. \(18.2^{\circ}\mathrm{C}\)
The triple points of neon and carbon dioxide are \(24.57\) K and \(216.55\) K respectively. The value of these temperatures on Fahrenheit scales will be:
| 1. | \(-415.44^\circ ~\mathrm{F} ,~-69.88^\circ ~\mathrm{F}\) |
| 2. | \(-248.58^\circ ~\mathrm{F} ,~-56.60^\circ~ \mathrm{F}\) |
| 3. | \(315.44^\circ ~\mathrm{F} ,~-69.88^\circ ~\mathrm{F}\) |
| 4. | \(415.44^\circ ~\mathrm{F} ,~-79.88^\circ~ \mathrm{F}\) |
1. \(T_A = {5 \over 7}T_B\)
2. \(T_A = { 4 \over 7}T_B\)
3. \(T_A = { 6 \over 7}T_B\)
4. \(T_A = T_B\)
A large steel wheel is to be fitted onto a shaft of the same material. At 27 °C, the outer diameter of the shaft is 8.70 cm and the wheel's central hole has a diameter of 8.69 cm. The shaft is cooled using ‘dry ice’. At what temperature of the shaft does the wheel slip on the shaft?
(Assume the coefficient of linear expansion of the steel to be constant over the required temperature range and \(\alpha\) steel = \(1.20 \times 10^{-5} K^{-1}\))
2. -70°C
3. -69°C
4. -67°C
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