it is a striking colour
it is scattered
it has very high energy
its wavelength is the longest
Red light is used for signals as it has
Refraction of star light through the earth’s atmosphere causes
Refractive Index of glass with respect to water is
Refrigerators keep food unspoiled as
Relative humidity is expressed as
Remote-sensing device has an inbuilt source of
Richter scale is used for measuring
Rise of oil a wick is due to
Rocket works on the principle of
Roentgen discovered