Question

a coverging lens has a focal length of 50 mm. what is the power of the lens?
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Answer 1

Answer:

The power of lens is P=1/f and the unit of it Dioptres (D). Here the focal length f should be in meter.  

Here, f=50cm=(50/100)m=0.5m

So, P=+2D

I HOPE IT HELP YOU!

Explanation:

Answer 2

we know that convex lens converge light rays

P= 1/f

1 m = 1000mm

50 mm= 0.05 m

P=1/o.o5

P= 20 D