A monochromatic beam of light passes from a denser medium into a rarer medium. As a result [CPMT 1972]
Its velocity increases
Its velocity decreases
Its frequency decreases
Its wavelength decreases
A monochromatic beam of light passes from an optically denser medium into an optically rarer medium. As a result, ____.
When a beam of light moves from a rarer medium to a denser medium: