Refraction by Spherical Surfaces: Practice Problem & Solution
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, (2020-Covid)
Solution Explained:
To solve this problem, we apply the core principles of Refraction by Spherical Surfaces. Understanding the underlying formula is key to arriving at the correct answer below:
Power $P = 10 D$, so focal length $f = 1/10 m = 10 cm$. Using the lens maker's formula: $\frac{1}{f} = (\mu - 1)(\frac{1}{R_1} - \frac{1}{R_2})$. $\frac{1}{10} = (\mu - 1)(\frac{1}{10} - \frac{1}{-10}) = (\mu - 1)(\frac{2}{10})$. This gives $1 = 2(\mu - 1)$, resulting in $\mu = 3/2$.
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