Concepts Of Physics MCQ Edition [Volume 1]
- Exam
- Concepts Of Physics MCQ Edition [Volume 1]
- Subject
- Physics
- Chapter
- Geometrical Optics
Concepts Of Physics MCQ Edition [Volume 1] · Physics · Geometrical Optics
Determine the angle of minimum deviation for an equilateral prism...
Determine the angle of minimum deviation for an equilateral prism constructed from a material with a refractive index of . What is the corresponding angle of incidence for this deviation?
Options
- A60^{}^{{}^{\circ}} and 60^{}^{{}^{\circ}}
- B60^{}^{{}^{\circ}} and 30^{}^{{}^{\circ}}
- C30^{}^{{}^{\circ}} and 60^{}^{{}^{\circ}}
- D45^{}^{{}^{\circ}} and 45^{}^{{}^{\circ}}
Correct answer
A. 60^{}^{{}^{\circ}} and 60^{}^{{}^{\circ}}
Step-by-step solution
For an equilateral prism, the angle of the prism is A = 60^{}^{{}^{\circ}}.
The refractive index of the material is given as .
The relation between the refractive index, angle of prism, and angle of minimum deviation is:
Substituting the given values:
\sqrt{3} = \dfrac{\sin\left(\dfrac{60^{}^{{}^{\circ}} + \delta_m}{2}\right)}{\sin\left(\dfrac{60^{}^{{}^{\circ}}}{2}\right)}
\sqrt{3} = \dfrac{\sin\left(30^{}^{{}^{\circ}} + \dfrac{\delta_m}{2}\right)}{\sin(30^{}^{{}^{\circ}})}
\sqrt{3} = \dfrac{\sin\left(30^{}^{{}^{\circ}} + \dfrac{\delta_m}{2}\right)}{\dfrac{1}{2}}
\sin\left(30^{}^{{}^{\circ}} + \dfrac{\delta_m}{2}\right) = \dfrac{\sqrt{3}}{2}
Since \sin(60^{}^{{}^{\circ}}) = \dfrac{\sqrt{3}}{2}, we get:
30^{}^{{}^{\circ}} + \dfrac{\delta_m}{2} = 60^{}^{{}^{\circ}}
\dfrac{\delta_m}{2} = 30^{}^{{}^{\circ}} \Rightarrow \delta_m = 60^{}^{{}^{\circ}}
The corresponding angle of incidence at minimum deviation is given by:
i = \dfrac{60^{}^{{}^{\circ}} + 60^{}^{{}^{\circ}}}{2} = 60^{}^{{}^{\circ}}
Thus, the angle of minimum deviation is 60^{}^{{}^{\circ}} and the angle of incidence is 60^{}^{{}^{\circ}}.
The refractive index of the material is given as .
The relation between the refractive index, angle of prism, and angle of minimum deviation is:
Substituting the given values:
\sqrt{3} = \dfrac{\sin\left(\dfrac{60^{}^{{}^{\circ}} + \delta_m}{2}\right)}{\sin\left(\dfrac{60^{}^{{}^{\circ}}}{2}\right)}
\sqrt{3} = \dfrac{\sin\left(30^{}^{{}^{\circ}} + \dfrac{\delta_m}{2}\right)}{\sin(30^{}^{{}^{\circ}})}
\sqrt{3} = \dfrac{\sin\left(30^{}^{{}^{\circ}} + \dfrac{\delta_m}{2}\right)}{\dfrac{1}{2}}
\sin\left(30^{}^{{}^{\circ}} + \dfrac{\delta_m}{2}\right) = \dfrac{\sqrt{3}}{2}
Since \sin(60^{}^{{}^{\circ}}) = \dfrac{\sqrt{3}}{2}, we get:
30^{}^{{}^{\circ}} + \dfrac{\delta_m}{2} = 60^{}^{{}^{\circ}}
\dfrac{\delta_m}{2} = 30^{}^{{}^{\circ}} \Rightarrow \delta_m = 60^{}^{{}^{\circ}}
The corresponding angle of incidence at minimum deviation is given by:
i = \dfrac{60^{}^{{}^{\circ}} + 60^{}^{{}^{\circ}}}{2} = 60^{}^{{}^{\circ}}
Thus, the angle of minimum deviation is 60^{}^{{}^{\circ}} and the angle of incidence is 60^{}^{{}^{\circ}}.