All Questions
59
questions
1
vote
2
answers
72
views
Why total reflection happens at only 1 angle?
The critical angle can be intuitively understood by Snell's law.If the incident medium has a bigger diffraction index than the refracted medium then according to Snell's law the refracted ray will be ...
- 101
5
votes
4
answers
1k
views
How do parallel reflected rays meet to form image at infinity? If they never meet then how is image formed?
In my textbooks it is written that when an object is kept at focus, its image is formed at infinity and is real. But how is this possible because parallel lines never meet and it is necessary for rays ...
- 51
0
votes
2
answers
75
views
Is there a way to calculate the angle between the refracted and reflected rays given the refractive index?
Is there a way to calculate the refracted and reflected rays? I know we use Snell's law to calculate the refracted rays, but is there a formula to calculate the angle of the reflected rays, or does it ...
- 187
0
votes
0
answers
68
views
Finding the limiting refractive index of a rainbow
Give the limiting refractive index of a rainbow.
The raindrops are modelled as spherical droplets, with refractive index $n$, with parallel rays from the Sun incident on it. I have a very limited ...
2
votes
1
answer
201
views
Lenses and missing reflection
I am wondering why reflected rays are not considered with lenses. If a ray strikes a surface, another is reflected off that striking point; however, this is not added when studying lenses, only ...
- 23
0
votes
1
answer
39
views
Magnification of closely packed thin lenses, or of closely packed lens and mirror
I was taught how to calculate the equivalent foci in both the cases. And since the formulae resemble the simple mirror and lens maker formulae, teacher said that this system is behaving like a single ...
- 41
10
votes
2
answers
2k
views
Is it possible to witness a rainbow while facing the sun?
We know that a rainbow occurs due to the refraction and reflection of light inside raindrops. We also know that inside spherical raindrops total internal reflection is not possible. So some light is ...
- 123
33
votes
3
answers
3k
views
A Rainbow Paradox
I was studying the phenomena of the formation of a rainbow. In my book, the following diagram is given:
So, the rays at the red end of the spectrum make a larger angle with the incident ray than the ...
- 1,064
0
votes
1
answer
70
views
Combined reflection and refraction [closed]
Suppose a plane mirror is half-submerged in another medium (say water) and light rays are incident obliquely on mirror at the interface separating two media.
My questions -
(a)- Will reflected rays ...
- 3
2
votes
2
answers
2k
views
Why double rainbows have the orders of the color bands in them inverted?
I did some online search and found the explanation using the following two diagrams. It's not perfectly convincing to me. Or at least it is not clear to me in the following details of the process:
...
- 81
8
votes
2
answers
399
views
Can we trap a light ray in a prism (in geometric optics)?
In geometric optics, light rays can enter a (finite) prism of constant refractive index, and bounce off the edges as long as the incident angle is less than the critical angle of the medium.
Is there ...
- 2,141
1
vote
1
answer
85
views
Change in nature of image: Putting a concave mirror in water vs in air
I was wondering if we put a concave mirror in water, what will be the difference in the image formed by it in air vs water?
Exception: Here I mean except when rays come from infinity (e.g., sun) ...
- 1,064
2
votes
1
answer
65
views
Analysis of the reflection in metal
In order to solve the reflexion in a material with a complex index the solution I've found on textbooks is to define $\hat{n}\cos{\phi}:=a+bi$ where $\hat{n}=n_r+n_ii$ is the complex index and then ...
- 225
1
vote
3
answers
387
views
How does a rainbow show all of its colours?
My question is tied closely to this one, asked a while back on the website. As far as my understanding goes, a rainbow is formed by sunlight undergoing two refractions and a reflection inside ...
4
votes
2
answers
253
views
Rainbow reflections from salt crystals
Especially on a sunny day in the winter or spring, I often notice faint rainbows when I look down at the edge of the road by the curb. I am not sure what causes these rainbows, but I believe that ...
- 233