Absolute refractive indices of water and glass are $\frac{4}{3}$ and $\frac{3}{2}$ respectively. In which one of the two media is the speed of light more?
A lower refractive index means higher speed of light. Since the refractive index of water ($\frac{4}{3} = 1.33$) is less than that of glass ($\frac{3}{2} = 1.5$), the speed of light is more in water.
Find the magnification of the image formed by a spherical mirror from the following data :
$u = -20$ cm, $f = -15$ cm.
Draw a labelled ray diagram for the image formation by a concave mirror when an object is placed between its centre of curvature and focus.
