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

Multiple Choice

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) $3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$