Question

derive relation between the angles of prisms for dispersion without deviation

Answer 1

Answer:

ANSWER

When two prisms of different materials and different suitable angles are combined so at to produce only deviation but no dispersion in the path of light, such combination of prisms is called deviation without dispersion.

Condition for deviation without dispersion:

Resultant dispersion = (Angular dispersion of crown glass prism) + (Angular dispersion of flint glass prism)

0=(μ

v

−μ

r

)A+(μ

v

′

−μ

r

′

)−A

′

or

A

1

A

=−

(μ

v

−μ

r

)

μ

v

′

−μ

r

′

(To derive following formula of resultant deviation)

δ=(μ

y

−1)A+(μ

y

′

−1)A

′

or δ=(μ

y

−1)A+[1−w/w

′

]

Where:

w= (Dispersive power of crown prism)

w

′

= (Dispersive power of flint prism)