Question

An object is immersed in a fluid of refractive index \( \mu \). In order that the object becomes invisible when observed from outside, it should

• A. have refractive index equal to one.
• B. have refractive index same as surrounding fluid, that is, \( \mu \).
• C. absorb all light falling on it.
• D. behave as a perfect reflector.

Hint:

For invisibility in a medium, the refractive index of the object should match the refractive index of the surrounding medium.

Answer 1

The Correct Option is B

Step 1: Understanding the concept of invisibility.
For an object to become invisible when observed from outside, the light should not be refracted or reflected by the object. This can happen only when the refractive index of the object matches that of the surrounding medium. Thus, the object will become invisible when its refractive index is the same as that of the fluid, which is \( \mu \). Step 2: Conclusion.
Thus, the correct answer is (B) have refractive index same as surrounding fluid, that is, \( \mu \).