Find the power of a concave lens of focal length 2 m.

The power (P) of a lens is given by the reciprocal of its focal length (f) in meters. The formula for calculating the power of a lens is:

P = f/1

Given that the focal length (f) of the concave lens is 2 meters, you can substitute this value into the formula to find the power:

P = 1/2
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So, the power (P) of the concave lens is 0.5 Dioptres. The positive sign indicates that it is a diverging lens (concave lens).