Question

Monochromatic light refers to light that has ___.

• A. red and blue colour
• B. white and orange colour
• C. only one colour
• D. all colours

Answer 1

The correct option is C only one colour

Monochromatic light refers to light of a single wavelength, i.e constitutes only one colour.
White light has wavelength ranging from $400nm$ to $700nm$ and contains different colours in it. Hence, white light is not monochromatic but polychromatic instead.