Question

A. How long (in ns) does it take light to travel 1.0 m in a vacuum?

Answer 1

Answer:

a) 3.33 ns

b) Water distance = 0.75 m

Glass distance = 0.66 m

Diamond distance = 0.41 m

Explanation:

We take the speed of light, c = m/s.

Speed = distance/time

Time = distance/speed

a)

$t=\dfrac{1}{3.0\times10^{8}}=3.33\times10^{-9}$

t = 3.33 ns

b)

Refractive index, n = speed of light in vacuum / speed of light in medium

$n=\dfrac{c}{s}$

$s=\dfrac{c}{n}$

$d=s\times t$

$d=\dfrac{c}{n}\times \dfrac{1}{c}$

$d=\dfrac{1}{n}$

Thus, the distance traveled in the same time is numerically equal to the reciprocal of the refractive index.

For water n = 1.333

d = 1/1.333 = 0.75 m

For glass n = 1.517

d = 0.66 m

For diamond n = 2.417

d = 0.41 m