a converging lens has a focal length of 250 millimetre calculate its power and Express it according to sign convention
Dear Student
given:- focal length= 250 mm. or 25 cm.
now since it is a convex lens, so focal length would be positive.
so power of lens= 100/f(cm)
P= 100/25
P= 4 D
so power of lens is + 4 D.
Regards