Answer:
η = 0.7
Step-by-step explanation:
The refractive index of the material can be calculated by using the following formula:
where,
η = refractive index of the material = ?
c = speedof light in vaccuum = 3 x 10⁸ m/s
v = speed of light in this material = 4.3 x 10⁸ m/s
Therefore,
η = 0.7