There are two lenses one is convex of focal length 50cm and the other is concave lens of focal - Science - Light - Reflection and Refraction

Question

There are two lenses one is convex of focal length 50cm and the
other is concave lens of focal length 25 cm what is the power of
combination of these 2 lenses

I Am A Barbie Girl · Accepted Answer

Power of convex lens=1/f
where f=+50cm
f = +0 5m
p=1/0 5
p=2D
Focal length of concave lens= -25cm
f = -0 25m
P=1/-0 25
P=-4D
combination of their power=2D +(-4D)
= -2D

There are two lenses. one is convex of focal length 50cm and the other is concave lens of focal length 25 cm. what is the power of combination of these 2 lenses.