long wavelength
high intensity
high frequency
low refraction in the medium
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
Rolling friction is caused by _