Question:
The focal length of a concave mirror in air is \( f \). When the mirror is immersed in a liquid of refractive index \( \frac{3}{5} \), its focal length will become:
The focal length of a concave mirror in air is \( f \). When the mirror is immersed in a liquid of refractive index \( \frac{3}{5} \), its focal length will become:
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The focal length of a concave mirror is inversely proportional to the refractive index of the medium.
Updated On: Feb 26, 2025
- \( \frac{5}{3} f \)
- \( \frac{3}{5} f \)
- \( \frac{2}{3} f \)
- \( f \)
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The Correct Option is A
Solution and Explanation
Step 1: The effect of refractive index.
The focal length of a mirror in a medium is related to its focal length in air by the refractive index of the medium.
Step 2: Applying the formula. The focal length in the liquid is given by: \[ f_{\text{liquid}} = \frac{f}{n} \] Where \( n \) is the refractive index of the liquid. Substituting \( n = \frac{3}{5} \), the new focal length becomes \( \frac{5}{3} f \), corresponding to option .
Step 2: Applying the formula. The focal length in the liquid is given by: \[ f_{\text{liquid}} = \frac{f}{n} \] Where \( n \) is the refractive index of the liquid. Substituting \( n = \frac{3}{5} \), the new focal length becomes \( \frac{5}{3} f \), corresponding to option .
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