If the light leaves a glass block ( n = 1.5 )with an angle of refraction of 70°. what is the angle of incidence?

The angle of incidence is 38.8°.

Explanation:

let n1 = 1.5 be the refractive index of glass and ∅1 be the angle of incidence, let n2 be the  refractive index of air and ∅2 be the angle of refraction.

by Snell's law:

n1×sin(∅1) = n2×sin(∅2)

sin(∅1) = n2×sin(∅2)/n1

           = (1)×sin(70)/1.5

      ∅1 = 38.8°

Therefore, the angle of incidence is 38.8°.

what type of charge does it have? negative