Three liquids have same surface tension and have densities $\rho_1, \rho_2$ and $\rho_3$ $(\rho_1 > \rho_2 > \rho_3)$. In three identical capillaries rise of liquid is same. The corresponding angles of contact $\theta_1, \theta_2$ and $\theta_3$ are related as

The work done in splitting a water drop of radius 'R' into 64 droplets is (T is the surface tension of water)

A celsius and a Fahrenheit thermometer are dipped in boiling water. The temperature of water is lowered until the Farenheit thermometer shows $140^\circ$. What is the fall in temperature on the Celsius thermometer?

Rate of radiation by a black body is 'R' at temperature 'T'. Another body has same area but emissivity is 0.2 and temperature 3T. Its rate of radiation is