Draw a labelled diagram of a single movable pulley system used to raise a load. Indicate directions of load, effort and tension in the string.

What do you understand by invisible spectrum? How will you investigate the existence of ultraviolet radiation ?  

The total heat needed to heat $1 \mathrm{kg}$ of ice at $-10º\mathrm{C}$ to water at $100º\mathrm{C}$ is $7.77 \times {10}^5 \mathrm{J}$. Calculate the specific latent heat of ice.

Specific heat capacity of ice $=2100 {\mathrm{Jkg}}^{-1}{\mathrm{K}}^{-1}$

Specific heat capacity of water $=4200 {\mathrm{Jkg}}^{-1}{\mathrm{K}}^{-1}$