Cause Of Dispersion

Measures Of Dispersion

Assertion (A): On a clear summer night twinkling of stars is observed. Reason (R) : The twinkling of stars is caused by dispersion of star light by the atmosphere.

Dispersion Of Light|Angle Of Dispersion|Dispersive Power

Assertion: The rainbow is seen sometimes in the sky when it is raining. When one sees a rainbow, one's back is towards the sun. Reason: Interanl reflection from water droplet causes dispersion. The final ray is in the backward direction.

Two thin prisms are combined such that they neither produce any average deviation nor do they cause any dispersion when white light is incident on the combination. Angle of one prism is A = 2° and refractive index of its glass for red, yellow and violet lights are 1.49, 1.50 and 1.51 respectively. Find the dispersive power of the glass of the other prism.

Statement-1 : The rainbow is seen sometimes in the sky when it is raining. When one sees a rainbow, one's back is towards the sun. Statement-2 : Internal reflection from water droplet causes dispersion. The final rays is in the backward direction.