CBSE (Science) Class 12CBSE
Share
Notifications

View all notifications

A Ray PQ Incident on the Refracting Face BA is Refracted in the Prism BAC as Shown in the Figure and Emerges from the Other Refracting Face AC as RS Such that AQ = AR. - CBSE (Science) Class 12 - Physics

Login
Create free account


      Forgot password?

Question

A ray PQ incident on the refracting face BA is refracted in the prism BAC as shown in the figure and emerges from the other refracting face AC as RS such that AQ = AR. If the angle of prism A = 60° and refractive index of material of prism is `sqrt3 `. Calculate angle θ.

Solution

The angle of the prism is A = 60°. It is also given that AQ = AR. Therefore, the angles opposite to these two sides are also equal.

∠AQR = ∠ARQ

Now, for a triangle

∠A + ∠AQR + ∠ARQ = 180°

∴ ∠AQR = ∠ARQ = 60°

∴ r1=r2 = 30°  (∠AQO = ∠ARO = 90°)

∴ r1 + r2 = 60°

When r1 and r2 are equal, we have i = e. Now, according to Snell’s law,

`mu=sini/sinr_1`

`:.sini=musinr_1=sqrt3 sin30 =sqrt3/2`

∴ i = 60°

Now, the angle of deviation θ is

θ = i + e - A

∴ θ = 60 + 60 -60

∴  θ = 60°

  Is there an error in this question or solution?

Video TutorialsVIEW ALL [2]

Solution A Ray PQ Incident on the Refracting Face BA is Refracted in the Prism BAC as Shown in the Figure and Emerges from the Other Refracting Face AC as RS Such that AQ = AR. Concept: Dispersion by a Prism.
S
View in app×