Question

The optical path of a monochromatic light is the same if it goes through 2.00 cm of glass or x cm of ruby. If the refractive index of glass is 1.510 and that of ruby is 1.760, the value of x is

• A. $1.6cm$
• B. $1.68cm$
• C. $1.716cm$
• D. $1.74cm$

Answer 1

The correct option is C $1.716cm$

Optical path $=\mu t$
So, ${\mu }_1{t}_1={\mu }_2{t}_2$ $\left(opticalpathissame\right)$
$\Rightarrow 1.510\left(2\right)=1.760\left(x\right)$
$\Rightarrow x=\frac{1.510\times 2}{1.760}$

$=1.716cm$