Question

If a lens can converge the sun rays at a point 20cm away from its optical centre the power of this lens is :-
a) 2D
b) -2D
c) 5D
d) -5D

Answer 1

Answer:

the answer should be 2D

since it is a convex lense f and R are always positive so dioptre will be positive

Answer 2

Answer:

option a) 2D

Explanation:

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