Question

A concave lens forms a virtual image 0.4 times the size of the object. The distance between object and image is 5.3 cm. Find the focal length of the lens. Answer in units of cm.

Answer 1

To find the focal length of the concave lens, we can use the lens formula and the magnification formula. By substituting the given values and solving simultaneously, the focal length is found to be 21.54 cm.

Step-by-step explanation:

The focal length of a concave lens can be found using the lens formula: 1/f = 1/v - 1/u, where f is the focal length, v is the image distance and u is the object distance.

In this case, the image distance is given as 5.3 cm and the magnification is given as 0.4 times the size of the object. The magnification formula is: magnification = -v/u.

By substituting the given values into these formulas and solving simultaneously, we can find the focal length of the concave lens to be 21.54 cm.