Which one of the following colours is least deviated by the glass prism?

Answer & Explanation

Correct answer: (B) Red

• Red light is the least deviated (bent) when passing through a glass prism. This is because red light has the longest wavelength and lowest frequency among all visible light colours, and the degree of deviation is inversely proportional to wavelength — longer the wavelength, lesser the deviation.

Dispersion of White Light through a Prism

• When white light passes through a glass prism, it splits into seven constituent colours known as VIBGYOR (Violet, Indigo, Blue, Green, Yellow, Orange, Red).
• This phenomenon is called dispersion of light. Each colour bends by a different amount because each has a different wavelength and refractive index in glass.