For a prism of the angle A, of refractive index n 2 placed in a medium
of refractive index n1,
n
n
n
A
D
A
m
21
2
1
2
2
=
=
+
(
)


(
)
sin
/
sin
/
where Dm is the angle of minimum deviation 6 For refraction through a spherical interface (from medium 1 to 2 of
refractive index n1 and n 2, respectively)
2
1
2
1
n
n
n
n
v
u
−R
−
=
Thin lens formula
1
1
1
v
u
f
−
=
Lens maker’s formula
1
1
1
2
1
1
1
2
f
n
n
n
R
R
=
−
(
)
−




R1 and R2 are the radii of curvature of the lens surfaces f is positive
for a converging lens; f is negative for a diverging lens