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)

Violet

Answer 2

$\because \mu=\frac{\text { Real depth }}{\text { apparent depth }}$
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.