When a ray incident occurs in one medium and goes in another medium, this phenomenon is called refraction. And when a ray incident occurs at one medium and goes in the same medium after touching its surface, this is called reflection.Angle of deviation is an angle between the original ray and the final ray. In other words, the angle of deviation is the inclination between the original and final ray.
The angle of deviation can be found by using the formula
n = sin(A+δm/2)/sin(A/2)
Substituting the values,
For small angles, sinθ≈θ
n= A + δm/A/2
1.5 = 6 + δm/6
6 + δm = 9
δm = 3∘
The angle of deviation produced by the prism is 3∘