CBSE Class 12 · 2010 · Delhi · Geometrical OpticsVery Short Answer

A glass lens of refractive index

1.45

disappears when immersed in a liquid. What is the value of the refractive index of the liquid?

Answer: $1.45$ .

Solution

A lens becomes invisible (loses its power) only when the surrounding medium has the \emph{same} refractive index as the lens, so that no refraction occurs at its surfaces.

μ_{liquid} = μ_{glass} = 1.45

CBSE Class 12 Board · 2010 · Delhi · Subjective

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