Answer:
refractive index of plastic is 1.42
Explanation:
When light ray enters from one medium to other medium then due to transition of light it bends away or towards the normal, this phenomenon is known as refraction of light
So here we know that
[tex]n_1 sin i = n_2 sin r[/tex]
here we have
[tex]n_2 = \frac{4}{3}[/tex]
[tex]i = 62.9^o[/tex]
[tex]r = 70.9^o[/tex]
now we have
[tex]n_1 sin62.9 = (\frac{4}{3}) sin70.9[/tex]
[tex]n_1 = 1.42[/tex]
