Question

If the focal length of a lens is 2 metres What is the power of the lens

Answer 1

0.5D ( by relation between the power of the lens and focal length)

Answer 2

*Power of the lens is 0.5 D.

*Power is the reciprocal of focal length where focal length should be measured in meter.

So,   power=1/f

   where f is focal length of lens in meter.

* diopter (D) is the SI unit of power of lens.

*Power can also be explained as the ability of lens to converge or diverge the light falling on it.

*In other words it gives bending strength of a lens.

*Here given focal length,f=2m

     then,

             power,p=1÷2=0.5 D