Question

Calculate the focal length of lens, if its power is 2.5 d.

Answer 1

Answer:

40 cm

Explanation:

$p = \frac{1}{f} \\ 2.5 = \frac{1}{f} \\ f = \frac{1}{2.5} m \\ f = \frac{100}{2.5} cm \\ f = 40cm$

Answer 2

Answer:

Hey mate

P=1/f

2.5=1/f

1/2.5=f

10/25=f

0.4=f

Note:

The unit will be same as given in your question if not given use S. I unit.

Explanation:

hope it will help you

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