Assertion: When a convex lens (μ g =3 / 2) of focal length f is dipped in water (μw=(4/3)), its focal length becomes 4 f. Reason: The focal length of convex lens is always half of its radius of curvature.

Question

Assertion: When a convex lens (μ g =3 / 2) of focal length f is dipped in water (μw=(4/3)), its focal length becomes 4 f. Reason: The focal length of convex lens is always half of its radius of curvature. (A) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion. (B) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion. (C) If the Assertion is correct but Reason is incorrect. (D) If the Assertion is incorrect and Reason is correct.

Tardigrade Admin · Accepted Answer

fw=f ( a μg-1/(( a μg) a μw-1))=f (((3/2)-1)/((3 / 2)4 / 3-1))=4 f

Q. Assertion : When a convex lens $(μ_{g} = 3/2)$ of focal length $f$ is dipped in water $(μ_{w} = \frac{4}{3})$ , its focal length becomes $4 f$ .
Reason : The focal length of convex lens is always half of its radius of curvature.

If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

If the Assertion is correct but Reason is incorrect.

If the Assertion is incorrect and Reason is correct.

$f_{w} = f \frac{_{a} μ _{g} - 1}{( \frac{_{a} μ _{g}}{_{a} μ _{w}} - 1 )} = f \frac{( \frac{3}{2} - 1 )}{( \frac{3/2}{4/3} - 1 )} = 4 f$

Q. Assertion : When a convex lens (μg​=3/2) of focal length f is dipped in water (μw​=34​), its focal length becomes 4f. Reason : The focal length of convex lens is always half of its radius of curvature.