A uniform metal rod is used as a bar pendulum. If the room temperature rises by $10°C$, and the coefficient of linear expansion of the metal of the rod is $2 \times 10^{-6}$ per $°C,$ the period of the pendulum will have percentage increase of

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

A unit scale is to be prepared whose length does not change with temperature and remains $20\,cm$, using a bimetallic strip made of brass and iron each of different length. The length of both components would change in such a way that difference between their lengths remains constant. If length of brass is $40\,cm$ and length of iron will be$...cm$

$\left(\alpha_{\text {iron }}=1.2 \times 10^{-5} K ^{-1}\right.$ and $\left.\alpha_{\text {brass }}=1.8 \times 10^{-5} K ^{-1}\right)$.

A brass disc fits simply in a hole of a steel plate. The disc from the hole can be loosened if the system

Density of substance at $0°C$ is $10\, gm/cc$ and at $100°C,$ its density is $9.7\, gm/cc$. The coefficient of linear expansion of the substance will be

A metal rod of Young's modulus $Y$ and coefficient of thermal expansion $\alpha$ is held at its two ends such that its length remains invariant. If its temperature is raised by $t^{\circ} C$, the linear stress developed in it is