Temperature

Q. The temperature of a gas is raised from ${27}^{\circ }\text{C}$ to ${927}^{\circ }\text{C}$. The root mean square speed

1. becomes $\sqrt{\frac{927}{27}}$ times the earlier value.
2. remains the same.
3. gets halved.
4. gets doubled.

Q. The temperature, at which the root mean square velocity of hydrogen molecules equals their escape velocity from the earth is closest to
(Take $g=10m/s^2$)

1. ${10}^4\text{K}$
2. $650\text{K}$
3. $3\times {10}^5\text{K}$
4. $800\text{K}$

Q.

The temperature at which the root mean square velocity of a molecule will be doubled than at ${100}^{\circ }C$

1. ${1219}^{\circ }C$

2. ${1492}^{\circ }C$

3. ${400}^{\circ }C$

4. 400 K

Q. The figure shows the face and interface temperature of a composite slab consisting of four materials, of identical thickness, through which the heat transfer is steady. Which material has minimum thermal conductivity?

1. $\text{a}$
2. $\text{b}$
3. $\text{c}$
4. $\text{d}$

Q. When a gas cylinder is kept on an accelerating van then its temperature will

1. increase
2. decrease
3. remain constant
4. first increase then decrease

Q. Inner surface of a cylindrical shell of length $l$ and of material of thermal conductivity $k$ is kept at constant temperature $T_1$ and outer surface of the cylinder is kept at constant temperature $T_2$ such that $(T_1>T_2)$ as shown in figure. Heat flows from inner surface to outer surface radially outward. Inner and outer radii of the shell are $R$ and $2R$ respectively. Due to lack of space this cylinder has to be replaced by a smaller cylinder of length $\frac{l}{2}$ inner and outer radii $\frac{R}{4}$ and $R$ respectively and thermal conductivity of material $nk$. If rate of radially outward heat flow remains same for same temperatures of inner and outer surface i.e., $T_1$ and $T_2$, then find the value of $n$.

Q. The temperature, at which the root mean square velocity of hydrogen molecules equals their escape velocity from the earth is closest to
(Take $g=10m/s^2$)

1. ${10}^4\text{K}$
2. $650\text{K}$
3. $3\times {10}^5\text{K}$
4. $800\text{K}$

Q. A heated body emits radiation which has maximum intensity at frequency $v_m$. If the temperature of the body is doubled:

1. the maximum intensity radiation will be at frequency $2v_m$
2. the maximum intensity radiation will be at frequency $\frac{1}{2}{v}_m$
3. the total emitted energy will increase by a factor 16
4. the total emitted energy will increase by a factor 2

Q.

The absolute zero is the temperature at which :

1. water freezes.

2. all substances exist in solid state.

3. molecular motion ceases.

4. ice melts.

Q.

We understand 'temperature' as a measure of the 'hotness' or 'coldness' of a body. Which of these properties do you think explicitly depend on the temperature?

1. Density of a liquid

2. length of a metal rod

3. pressure exerted by a gas inside a closed chamber

4. all of the above

Q.

If there are two objects in thermal equilibrium in one frame, they will be in thermal equilibrium in all frames

1. True

2. False

Q. The figure shows the face and interface temperature of a composite slab consisting of four materials, of identical thickness, through which the heat transfer is steady. Which material has minimum thermal conductivity?

1. $\text{a}$
2. $\text{b}$
3. $\text{c}$
4. $\text{d}$