Question

Angles of deviation for extreme colours are given for different prisms. Select the one having max dispersive power of its material.
(a) 7°, 10°. (b) 8°, 11°
(c) 12°, 16°. (d) 10°, 14°​

Answer 1

Answer:

Option (a) 7°, 10°

Step-by-step explanation:

Dispersive power of a medium is given by

$\boxed{\omega=\frac{\delta_F-\delta_C}{\delta_D}}$

where, $\delta_F$ and  $\delta_C$ are the angles of deviation for the blue and red colours respectively. Also called the difference in the angles of deviation of extreme colours.

$\delta_D$ is the deviation for the yellow colour or mean deviation which is the average of the extreme deviations

Thus, where the difference in $\delta_F$ and  $\delta_C$ divided by the mean deviation is most, will have the maximum dispersive power

In Option (a) the value of ω = 3/8.5 = 0.35

In Option (b) the value of ω = 3/9.5 = 0.32

In Option (c) the value of ω = 4/14 = 0.29

In Option (d) the value of ω = 4/12 = 0.33

Therefore the maximum dispersive power is that of the values given in Option (a)

Answer 2

Answer:

Answer:

Option (a) 7°, 10°

Step-by-step explanation:

Dispersive power of a medium is given by

\boxed{\omega=\frac{\delta_F-\delta_C}{\delta_D}}

ω=

δ

D

δ

F

−δ

C

where, \delta_Fδ

F

and \delta_Cδ

C

are the angles of deviation for the blue and red colours respectively. Also called the difference in the angles of deviation of extreme colours.

\delta_Dδ

D

is the deviation for the yellow colour or mean deviation which is the average of the extreme deviations

Thus, where the difference in \delta_Fδ

F

and \delta_Cδ

C

divided by the mean deviation is most, will have the maximum dispersive power

In Option (a) the value of ω = 3/8.5 = 0.35

In Option (b) the value of ω = 3/9.5 = 0.32

In Option (c) the value of ω = 4/14 = 0.29

In Option (d) the value of ω = 4/12 = 0.33

Therefore the maximum dispersive power is that of the values given is option (a)

Hope it helps!