A lens has a focal length of, 10 cm. What is the power of the lens and what is its nature ?

The optician's prescription for a spectacle lens is marked+ 0.5 D. What is the: (a) nature of spectacle lens?

(b) focal length of spectacle lens ?

A doctor has prescribed a corrective lens of power, -2 D. Find the focal length of the lens. Is the prescribed lens diverging or converging ?

The focal length of a lens is +150 mm. What kind of lens is it and what is its power ?

Fill in the following blanks with suitable words :

(a) The reciprocal of the focal length in ____ gives you the power of the lens, which is measured in........

(b) For _____ lenses, the power is positive while for diverging lenses, the power is negative