A paraxial ray parallel to the principal axis falls on a concave spherical mirror. After reflection, the ray passes through which point? 
AThe centre of curvature
BThe pole
CThe principal focus
DThe focal plane at infinity
Answer & Solution
Correct answer: C. The principal focus
For a concave mirror, paraxial rays parallel to the principal axis converge after reflection at the principal focus. This is one of the standard rules used in drawing ray diagrams for image formation.
Related questions
Which colour travels fastest in a glass prism?Dispersion happens because the refractive index differs with:Violet light has a wavelength of about:In the visible spectrum, red light lies at the:A lens of power minus 4.0 D is a concave lens of focal length:A prescribed lens of power plus 2.5 D is a convex lens of focal length:The power of a converging lens is:A lens of focal length one metre has a power of: