Question

The number of waves in a glass plate of thickness $4cm$ is same as in $5cm$ of vertical column o water of refractive index $4/3$, then refractive index of glass will be:-

• A. $5/3$
• B. $5/4$
• C. $16/14$
• D. $1.5$

Answer 1

The correct option is A $5/3$

${\mu }_{glass}=\frac{C}{V_{glass}}$

No at waves $=\frac{d}{\lambda }$

number of waves in glass $=\left(4\right)\times \left({\mu }_{glass}\right)$

Number of waves in water $=5\times {\mu }_{water}$

$4{\mu }_{glass}=\frac{5\times 4}{3}$

${\mu }_{glass}=5/3$