O, Y, Z and N,
O, X, M and Z
P, X, Z and N
P, Y, M and Z,
Angle of prism=∠O, (angle between two refracting surfaces)
Angle of incidence=∠X(angle between incident ray and normal) ,
Angle of emergence=∠M(angle between emergent ray and normal)
Angle of deviation=∠Z(angle between incident ray and emergent ray)