we know that the speed of light in a vacuum is 3.0 x 10^8 m/s (18,000 mi/sec). If light travels through thick plastic with a speed of 1.75 x 10^8 m/s, what is the index of refraction through plastic?

index of refraction= speed of light in space/speed of light in material=3.0/1.75=

To find the index of refraction through plastic, we can use the formula:

Index of Refraction (n) = Speed of Light in a Vacuum (c) / Speed of Light in the medium (v)

Given:
Speed of Light in a Vacuum (c) = 3.0 x 10^8 m/s
Speed of Light in Plastic (v) = 1.75 x 10^8 m/s

By substituting the values into the formula, we get:

n = c / v = (3.0 x 10^8 m/s) / (1.75 x 10^8 m/s)

To simplify the calculation, we can divide the numerator and denominator by 10^8 to get:

n = (3.0 / 1.75) x (10^8 / 10^8)

Simplifying further, we have:

n = 1.714 x 1

Thus, the index of refraction through plastic is approximately 1.714.