Find the odd man out :

1. Reflection, Dispersion, Refractive index, Refraction.
Ans. Refractive index. Refractive index is a value while the rest are natural

phenomenon of light.
2. Brown, Blue, Green, Red.

Ans. Brown. It is not the component of while light. Blue, red and green are components of white light.
3. Twinkling of stars, Advanced sunrise, Delayed sunset, Blue sky.
Ans. Blue sky. This is because of scattering of light, while the others are due to

atmospheric refraction.
4. Dispersion, Mirage, Refraction, Induction.

Ans. Induction. It is related to electric current, while others are phenomena of light.