Question

A convex lens of power +5D is placed in contact with a concave lens of power -4D . What is the
nature of focal length of the combination

Answer 1

Explanation:

A convex lens of power +5 D is placed in contact with a concave lens of power -4 D. What is the power of combination and nature of lens combination ? =5D-4D=+1D. The combination will behave as a converging lens.

Answer 2

P = P1 +P2

P = +5D + (-4D)

P = +1 D

so power is in positive

therefore, it is a convex lens which has a nature of converging lens.

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