Question

A plane glass plate is placed over a various coloured letters (violet, green, yellow, red). The letter which appears to raised more

• A. Red
• B. Yellow
• C. Green
• D. Violet

Answer 1

Answer: (D)

$\because \mu =\frac{\text{ Real depth }}{\text{ apparent depth }}$
where, $\mu$ reflective index of medium
$\Rightarrow$ Apparent depth $=\frac{\text{ Real depth }}{\mu }$
But, $\mu \propto \frac{1}{\lambda }$
$\because {\lambda }_v<{\lambda }_g<{\lambda }_y<{\lambda }_r$

Thus, ${\mu }_v$ is greater to all of them
$\therefore$ Apparent depth is minimum for violet.
It means that the violet letter appear raised more.