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प्रश्न
The power of a lens is, −2 D. What is its focal length?
The power of a lens is –2 D. What is the focal length and nature of the lens?
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उत्तर
Power of a lens is given by:
Power of a lens (P) = `1/"focal length (f in meters)"`
`p=1/f`
`⇒f=1/p`
`⇒f=1/-2`
f = −0.5 m
Since the power of the lens is negative, the lens is a concave lens.
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