Light having a speed in vacuum of $3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$ enters a liquid of refractive index $2.0$. In this liquid, its speed will be
A) $0.75 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$
B) $6.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$
C) $1.5 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$
D) $0.67 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$
E) $3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$

Question

Quizplus · Accepted Answer

The speed of light in a medium is given by $ v = \frac{c}{n} $, where $ c $ is the speed of light in vacuum and $ n $ is the refractive index. Here, $ v = \frac{3.0 \times 10^8 \, \mathrm{m/s}}{2.0} = 1.5 \times 10^8 \, \mathrm{m/s} $.

Light Having a Speed in Vacuum Of 3.0×108 m/s3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }3.0×108 m/s

Light Having a Speed in Vacuum Of $3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$