A simple microscope is used to see the object first in blue light and then in red light. Due to the change from blue to red light, what is the effect on its magnifying power?

The angle of minimum deviation produced by a thin prism in air is $\delta_1$. What will be the minimum deviation ($\delta_2$) if the prism is immersed in liquid ?
$\left[ {}^a n_g = \dfrac{3}{2}, \ {}^a n_\ell = \dfrac{1}{3} \right]$

In the phenomenon of refraction of light for the same angle of incidence

An equiconvex lens of focal length F is cut in to two equal parts along the vertical axis. The focal length of each part will be