" 7.What will be the focal length of a lens whose power is given as "+2.0" D? "1

The focal length of a lens of power + 4D is :

What is focal length of a lens of power 2.5 D ?

The focal length of a lens with power 2.5 D is …………………..

Find the focal length of a lens having -0.5 D power.

Doctor has prescribed a lens having power +1.5 D . What will be the focal length of the lens? What is the type of the lens and what must be the defect of vision?