Question

Assertion (A): A convex lens, when immersed in a liquid, disappears.
Reason (R): The refractive indices of the material of the lens and the liquid are equal.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false and Reason (R) is also false.

Hint:

When studying optics, it's essential to understand how the refractive index affects light transmission and bending at interfaces. Similar refractive indices can make objects visually disappear in mediums.

Answer 1

The Correct Option is A

The given question involves understanding why a convex lens might disappear when immersed in a liquid. Let's explore this using principles of physics related to refraction and the behavior of light through different media.

Assertion (A): A convex lens, when immersed in a liquid, disappears.

Reason (R): The refractive indices of the material of the lens and the liquid are equal.

The assertion and reason provided are closely tied to the concept of refractive index. Let's examine why:

• Refractive Index: The refractive index of a material determines how much light bends when it enters that material from another medium. The lens is visible in the air because its refractive index is different from that of the air, creating refraction and thus, visibility.
• When Immersed in Liquid: If the lens and the liquid have the same refractive index, light doesn't bend when passing through the lens. This lack of bending or refraction means there's no change in the path of light, so the lens becomes invisible.

Conclusion: Both the assertion and the reason are true; the convex lens indeed disappears in a liquid when both have identical refractive indices. Thus, the reason correctly explains the assertion.

Correct Option: Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).