Question

A plane glass slab is kept over various colour letters, the letter which appears least raised is:

• A. red
• B. violet
• C. green
• D. blue

Answer 1

Answer: (A)

red

Answer 2

Refractive index
$\mu =\frac{\text{real depth}}{\text{apparent depth}}$
For red colour, refractive index is minimum, i.e., it will have maximum apparent depth and hence, appears least raised.