A convex lens of focal length `10cm` and concave lens of focal length `20 cm` are kept `5 cm` apart. The focal length of the equivalent lens is

A concave lens of focal length 12 cm and a convex lens of focal length 20 cm are kept in contact with each other . Find the focal length of the combination .

A convex lens of focal length 80 cm and a concave lens of focal length 50cm are placed in contact. The resulting will be—

If the convex lens of focal length 10 cm and a concave lens of focal length 50 cm are kept in contact with each other. What will be the focal length of the combination ?

A thin convex lens of focal length 10 cm and a thin concave lens of focal length 20 cm are in contact. The combination acts as :

A convex lens of focal length 20 cm and a concave lens of focal length 10 cm are placed 20 cm apart. In between them an object placed at distance x from the convex lens. What will be the linear magnification produced convex lens and concave lens individually ?

A convex lens of focal length 20 cm and a concave lens of focal length 10 cm are placed 20 cm apart. In between them an object placed at distance x from the convex lens. What will be the linear magnification produced convex lens and concave lens individually ?

A concave lens of focal length 12 cm and a convex lens of focal length 20 cm are kept in contact with wach other. (i) Find the focal length of the combination. (ii) What will be the behaviour fo the combination ?

If a convex lens of focal length 20 cm and a concave lens of focal length 30 cm are kept in contract with each other. What will be the focal length of the combination ?

A convex lens of focal length 10 cm is placed in contact with a concave lens of focal length 20 cm. The focal length of this combination of lenses will be:

A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are joined together. The power of the combination will be