Question

When a lens of refractive index $n_{1}$ is placed in a liquid of refractive index $n_{2}$ the lens looks to be disappeared only if

• A. $n_{1}=n_{2} / 2$
• B. $n_{1}=3 n_{2} / 4$
• C. $n_{1}=n_{2}$
• D. $n_{1}=5 n_{2} / 4$

Answer 1

Answer: (C)

$n_{1}=n_{2}$

Answer 2

If refractive index of lens $n_{1}$ is equal to refractive index of liquid $n_{2}$ , then lens be haves as a plane glass plate and becames invisible in the medium.