What will be the time by light to travel 2 cm thickness of glass of refractive index 1.5?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → $10^{10} s$
Time taken (t) by light to travel through 2 cm (d) of a glass with refractive index (u) = 1.5 is -
$t=\frac{d}{v}$
where,
v = velocity of light in glass = $\frac{c}{u}$
$∴t=\frac{d×u}{c}=\frac{0.02×1.5}{2^3×10^8}$
$=10^{10} s$