A convex lens having power 5 D is placed in contact with a concave lens having power -3 (D) The focal length of the combination will be

Correct option is A

The correct answer is (a) 50 cm.
Explanation:
To calculate the focal length of the lens combination, we use the formula:

Now, the relationship between power P (in diopters) and focal length f (in meters) is:

Thus, the focal length of the combination is 50 cm.
Information Booster:
· Convex Lens: Has positive power and converges light rays.
· Concave Lens: Has negative power and diverges light rays.