NEET 2022, Physics Q5: Thin Lens and Mirrors

NEET2022Physics

A biconvex lens has radii of curvature, 20 cm each. if the refractive index of the material of the lens is 1.5, the power of the lens is :-

Solution

For a biconvex lens with sign convention, $R_{1} = + 20$ cm $= + 0.2$ m and $R_{2} = - 20$ cm $= - 0.2$ m.

Lensmaker's equation: $P = \frac{1}{f} = (μ - 1) (\frac{1}{R _{1}} - \frac{1}{R _{2}})$ .

$P = (1.5 - 1) (\frac{1}{0.2} - \frac{1}{- 0.2}) = 0.5 \times \frac{2}{0.2} = 5$ D.

Concept behind this question

Concept-wise practice with instant solutions on Fundamenthol.