The power of a convex lens of focal length 2 m is …………………

What do you mean by power of a lens ? What is the SI unit of the power of a lens ? Calculate the power of a concave lens of focal length 25 cm.

What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.

Calculate the power of a lens of focal length 25 cm .

A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12 cm from P. At what point does the beam converge if the lens is a convex lens of focal length 20 cm?

An object of height 3 cm is placed in front of a convex lens of focal length 20 cm at a distance of 30 cm. What is the distance to the image formed ?

An object of height 3 cm is placed in front of a convex lens of focal length 20 cm at a distance of 30 cm. What is the nature of the image?

An object of height 3 cm is placed in front of a convex lens of focal length 20 cm at a distance of 30 cm. What is the height of the image ?