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The power of a biconvex lens is 10 dioptre and the radius of curvature of each surface is 10 cm. Then the refractive index of the material of the lens is,
Detailed Solution
$f=\dfrac{1}{P}=\dfrac{1}{10}$ m $=10$ cm. Using $\dfrac{1}{f}=(\mu-1)\left(\dfrac{1}{R_1}-\dfrac{1}{R_2}\right)$ with $R_1=+10$ cm, $R_2=-10$ cm: $\dfrac{1}{10}=(\mu-1)\left(\dfrac{1}{10}+\dfrac{1}{10}\right)=(\mu-1)\dfrac{1}{5}\Rightarrow\mu-1=\dfrac{1}{2}\Rightarrow\mu=\dfrac{3}{2}$.