It happens because in solids the amplitude of wave is less then other medium therefore distance travelled is less in solids therefore speed is increased.

Capillary action is the phenomenon by which any liquid rises up in a wick or tube. It is due to surface tension of liquids. The height of rice up of liquid is depend upon surface tension of the water. This is occurs in small plants also.

Superconductor is the property in which 0 resistence obtained at a certain temperature and in a some substance. Ex. Mercury which shows superconductivity phenomena below the temperature 4. 3 k.

Light waves are transverse waves they do not require material medium to travel. Hence they are called electromagnetic waves. Light waves travel in vacuum with the velocity 3*10^7 m/s.