The power of a lens is - 5D
(i) find its focal length.
(ii) name the type of lens.

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Solution

focal length = $\frac{1}{P}$ = $\frac{100}{- 5}$ =-20 cm
It is a concave lens

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The power of a lens is - 5D (i) find its focal length.(ii) name the type of lens.

focal length = 1P=100−5=-20 cmIt is a concave lens

The power of a lens is - 5D
(i) find its focal length.
(ii) name the type of lens.

focal length = $\frac{1}{P}$ = $\frac{100}{- 5}$ =-20 cm
It is a concave lens