Collect the information about he lenses available in an optical shop. Find out how the focal length of a lens may be determined by the given'power' of the lens.

If the focal length of a lens fis in cm, then write the formula of power of lens.

Through an experiment, find out the focal length of the lens.

Power of a lens is 4D, then the focal length of the lens will be_____

The focal length of the convex lens is 10m . What is its power ?

From the given figure, what is the focal length of eye lens ?

Find the minimum and maximum focal lengths of the eye lens.

A convex lens and concave lens of focal length +20 cm and -30 cm respectively . Then find the power of each lens. Find the focal length of combined lens. And find the combined power of the lenses (+5D,-3.3D, +60 cm , + 1.7 D)

What is the relation between Power and Focal length of the lens ?