Answer:
refractive index = 2.5
Explanation:
Refractive index given by the ratio of speed of light in air or vaccum to the speed of light in the medium
ñ = C/V
where C = speed of light in vacuum
v = Speed of light in medium
(3.0 × 10^8)/( 1.2 ×10^8)
= 2.5 ✓