The focal length of the lens of refractive index $\left( \mathbf{\mu = 1.5} \right)$ in air is 10 cm. If air is replaced by water of $\mathbf{\mu =}\frac{\mathbf{4}}{\mathbf{3}}\mathbf{,}$ its focal length is

Question

Dr. Abubacker · Accepted Answer

(c) $\frac{f_{w}\ ᷿}{f_{a}ₐ} = \frac{\mu - 1}{\frac{\mu_{w}}{\mu_{a}} - 1}$
$\frac{f_{w}\ ᷿}{10} = \frac{1.5 - 1}{1/8}$
$f_{w}\ ᷿ = \ \frac{0.5 - 10}{1/8} = 40\ cm$

Q. The focal length of the lens of refractive index $\left( \mathbf{\mu = 1.5} \right)$ in air is 10 cm. If air is replaced by water of $\mathbf{\mu =}\frac{\mathbf{4}}{\mathbf{3}}\mathbf{,}$ its focal length is

Explanation

Reviewed by Dr. Abubacker

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