Which mirror has a large field of view?

$(a)$ $A$ ray of light falls normally on a face of a glass slab. What are the values of angle of incidence and angle of refraction of this ray?
$(b)$ Light enters from air to a medium $X$. Its speed in medium $X$ becomes $1.5 \times 10^{8} \ m \ s^{-1}$. Speed of light in air is $3 \times 10^{8} \ m \ s^{-1}$. Find the refractive index of medium $X$.

$A$ convex mirror can be used to see a large image of a small object.

Write down four important characteristics of the image formed by a plane mirror.

Rays from the Sun converge at a point $15 \, cm$ in front of a concave mirror. Where should an object be placed so that the size of its image is equal to the size of the object?

$A$ thin lens has a focal length of $-12\, cm$. Is it a convex lens or a concave lens?