Which of the following statements are correct?

A. The angle at minimum deviation of a prism is greater for violet light than that for red light.
B. The purpose of microscopes and telescopes is to increase the visual angle.
C. For the diffraction to take place the size of aperture or of the obstacle should be comparable to the wavelength of light.
D. The light scattered in the direction of the incident light is always plane polarised.
E. The source and its virtual image can behave as a coherent sources.

Choose the correct answer from the options given below:

A, B, C, E Only

The angle at minimum deviation of a prism is greater for violet light than that for red light.

$\delta = (\mu - 1)A$

$ \mu = A + \frac{B}{\lambda^2}$

$\Rightarrow \mu_v > \mu_r \Rightarrow \delta_v > \delta_r$

Diffraction occurs only when the size of the obstacle/aperture is comparable to the wavelength of the light used.

The emitted rays of light which are parallel to the direction/orientation of original rays are completely unpolarised. The emitted rays of light which are perpendicular to the direction of the original rays are completely polarised. The rays of light which are scattered in all other directions are partially polarised.

In the source and images method, a source and its image will act as a set of coherent sources, because the source and its image will have waves in-phase or constant phase difference as shown in the following figure.

only D is incorrect.