A steel rail of length $5\,m$ and area of cross-section $40\,cm^2$ is prevented from expanding along its length while the temperature rises by $10\,^oC$. If coefficient of linear expansion and Young's modulus of steel are $1.2\times10^{-5}\, K^{-1}$ and $2\times10^{11}\, Nm^{-2}$ respectively, the force developed in the rail is approximately

A hole is drilled in a copper sheet. The diameter of hole is $4.24 \,cm$ at $27.0^{\circ} C$. Diameter of the hole when it is heated to $35^{\circ} C$ is ...........

In a thermostat two metal strips are used, which have different ............

A copper rod of length $l_1$ and an iron rod of length $l_2$ are always maintained at the same common temperature $T$. If the difference $(l_2 -l_1)$ is $15\,cm$ and is independent of the value of $T,$ the $l_1$ and $l_2$ have the values (given the linear coefficient of expansion for copper and iron are $2.0 \times 10^{-6}\,C^{-1}$ and $1.0\times10^{-6}\,C^{ -1}$  respectively)

Two rods of different materials having coefficient of linear expansion $\alpha_1$and $\alpha_2$ and  Young's modulii $Y_1$ and $Y_2$ respectively are fixed between two rigid massive walls. The rods are heated such that they undergo the same increase in temperature. There is no bending of rods. If  $\alpha_1:\alpha_2= 2 : 3$, the thermal stress developed in two rods are equal provided $Y_1 : Y_2$ is equal to

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  .......... $cm$