Consider two thermometers $T_1$ and $T_2$ of equal length, which can be used to measure temperature over the range $\theta_1$ to $\theta_2$. $T_1$ contains mercury as the thermometric liquid, while $T_2$ contains bromine. The volumes of the two liquids are the same at the temperature $\theta_1$. The volumetric coefficients of expansion of mercury and bromine are $18 \times 10^{-5} \,K ^{-1}$ and $108 \times 10^{-5} \,K ^{-1}$, respectively. The increase in length of each liquid is the same for the same increase in temperature. If the diameters of the capillary tubes of the two thermometers are $d_1$ and $d_2$, respectively. Then, the ratio of $d_1: d_2$ would be closest to

A thin walled cylindrical metal vessel of linear coefficient of expansion $10^{-3} $ $^o C^{-1}$ contains benzenr of volume expansion coefficient $10^{-3}$ $^o C^{-1}$. If the vessel and its contents are now heated by $10^o C,$ the pressure due to the liquid at the bottom.

An iron bar of length $10\, m$ is heated from $0°C$ to $100°C.$ If the coefficient of linear thermal expansion of iron is $ 10 \times 10^{-6}{°C^{-1}}$, the increase in the length of bar is  .......... $cm$ 

A brass rod of length $50\; cm$ and diameter $3.0 \;mm$ is jotned to a steel rod of the same length and diameter. What is the change in length of the combined rod at $250\,^{\circ} C ,$ if the original lengths are at $40.0\,^{\circ} C ?$ Is there a 'thermal stress' developed at the junction? The ends of the rod are free to expand (Co-efficient of linear expansion of brass $=2.0 \times 10^{-5} \;K ^{-1},$ steel $=1.2 \times 10^{-5}\; K ^{-1} J$

Thermal expansion of a solid is due to the

Given below are two statement : one is labelled as Assertion $A$ and the other is labelled as Reason $R$.

Assertion $A$ : When a rod lying freely is heated, no thermal stress is developed in it.

Reason $R :$ On heating the length of the rod increases.

In the light of the above statements, choose the correct answer from the options given below