Question

What is the minimum distance between an object
and its real image formed by a convex lens of focal
length 20 cm?

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Answer 1

Answer:

1/v + 1/u = 1/f

1/x + 1/x = 1/20

2/x = 1/20

1 = x/40

1 = x/40

x = 40 cm is the minimum distance