Three plane mirrors form an equilateral triangle with each side of length $L$ There is a small hole at a distance $l>0$ from one of the corners as shown in the figure A ray of light is passed through the hole at an angle $\theta$ and can only come out through the same hole The cross section of the mirror configuration and the ray of light lie on the same plane Which of the following statement(s) is(are) correct?
- The ray of light will come out for $\theta=30^{\circ}$, for $0< l< L$.
- There is an angle for $l=\frac{L}{2}$ at which the ray of light will come out after two reflections.
- The ray of light will NEVER come out for $\theta=60^{\circ}$, and $l=\frac{L}{3}$.
- The ray of light will come out for $\theta=60^{\circ}$, and $0< l< \frac{L}{2}$ after six reflections.
The Correct Option is A, B
Solution and Explanation
(A) The ray of light will come out for \(θ = 30°\) , for \(0 < l < L.\)
(B) There is an angle for \(l = \frac{L}{2}\) at which the ray of light will come out after two reflections.
For option ‘A’ there will be normal incidence and ray retrace its path. For option ‘B’
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Concepts Used:
Ray Optics and Optical Instruments
Optics, deals with the determination of behaviour and the properties of light, along with its interactions with the matter and also with the instruments that are used to detect it.
Ray optics is also known as the geometrical optics and it is a branch of science which describes light propagation.
Reflection is the change in direction of light at an interface in-between two different media so that the wave-front returns into a medium from which it was originated.
Speed of light is the rate at which the light travels in free space.
A phenomenal change in image formed when the light is passed from one medium to another which is called Refraction.
Total Internal Reflection is the reflection of light when the light ray enters into a rarer medium from a denser medium and the angle of incidence is higher than the critical angle of incidence then that light ray will be reflected back to the denser medium.
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