Define the principal focus of a concave mirror.

Define ‘Principal focus' of a Concave Mirror. The distance between the centre of curvature and the pole of a concave mirror is 20 cm. Calculate the focal length of the mirror.

Define principal focus of a mirror.

Define the terms: principal focus

A 4 cm long needle lies along the principal axis of a concave mirror of focal length 18 cm in such a way that the end closer to the pole is 36 cm away from it Find the length of the image of the needle formed by the mirror.

10 cm long needle lies along the principal axis of a concave mirror of focal length 25 cm in such a way that the end closer to the pole is 40 cm away from it Find the length of the image of the needle formed by the mirror.

A 5.0 cm long needle lies along the principal axis of a concave mirror of focal length 20 cm in such a way that the end closer to the pole is 40 cm away from it. Find the length of the image of the needle formed by the mirror.

An object is held at the principal focus of a concave lens of focal length F. where is the image formed?

Define the principal axis of a lens.

Use the mirror equation to show that c) an object placed between the pole and focus of a concave mirror produces a virtual and enlarged image.