Tagged Questions
0
votes
0answers
19 views
Specular intensity [closed]
Im currently studying for an exam and have been going through some past papers on the subject, however i have come across a question that has recursively come up each year and the notes on it are not ...
1
vote
1answer
50 views
How large of a solar sail would be needed to travel to mars in under a year?
I'm attempting to approach this using the identity
$$F/A = I/c$$
I can solve for Area easily enough
$$A = F(c/I)$$
and I know the distance $d$ is
$$d=1/2(at^2)$$
But I'm having difficulty trying to ...
-2
votes
0answers
36 views
Physical Optics [closed]
Monochromatic light is used to illuminate a pair of narrow slits 0.3 mm apart and the interference pattern is observed on a source 0.91 mm away. The second dark band appears 3.0 mm from the center. ...
0
votes
1answer
28 views
Paraxial rays and marginal rays question
Paraxial rays are found to focus far away the lens whereas marginal rays focus near to the lens, why? I didn't find satisfactory answer in my academic book..
0
votes
0answers
13 views
Minimum thickness of bubble ensuring max reflectance
A soap bubble has index of refraction of 1.33. What minimum thickness of this bubble will ensure max reflectance of normally incident 530 nm light?
Ans is 99.6, but how do I get that?
I am ...
1
vote
1answer
35 views
Color of a Metal's Threshold Wavelength?
How do I find the color of the threshold wavelength if the metal has a threshold wavelength of $\mathrm{6.5\times 10^{-7}m}$? I know that converts down to $\mathrm{650\ nm}$, but can I still use the ...
1
vote
2answers
129 views
Relativistic Doppler effect derivation
This is about a step in a derivation of the expression for the relativistic Doppler effect.
Consider a source receding from an observer at a velocity $v$ along the line joining the two. Light is ...
0
votes
2answers
233 views
Young's Double Slit experiment question
Q-A beam of light consisting of two wavelenghts 600 nm and 450 nm is used to obtain interference in Young's Double Slit experiment (YDSE). Find the least distance from the central maximum where the ...
0
votes
1answer
65 views
What is the momentum of these emitted photons?
5 x 10^7 kg of radioactive material emits energy in the form of photons of red light (700 nm). (Note: photons have no mass.)
What is the momentum of each photon?
...
-1
votes
1answer
288 views
Focal length of Convex lens [closed]
A lens forms a real image of $3\ \text{cm}$ high of an object $1\ \text{cm}$ high. If the separation of object and image is $15\ \text{cm}$, find the focal length of the lens.
0
votes
1answer
98 views
Colors in the secondary rainbow reverse of that in the primary rainbow
Why the colors of Secondary rainbow is reverse of that in the color in the Primary rainbow?
What can be the possible reason among the following options
Because it is formed by one internal ...
1
vote
0answers
214 views
Malus' Law (Polarization) [closed]
Consider the image below:
Let $\theta_2$ be the angle between the axes of transmission of Polarizer 2 and Polarizer 3 and $\theta_3$ be the angle between the axes of transmission of Polarizer 3 ...
1
vote
0answers
66 views
Photon Statistics of a Coherent Gaussian Beam [closed]
Assume that a 100 pW He-Ne single-mode last emits light at 633 nm in a TEM00 Gaussian beam.
(a)What is the mean number of photons crossing a circle of radius equal to the waist radius of the beam ...
2
votes
0answers
86 views
Bandgap Spacing in Photonic Crystals
I am doing some self-study on photonics and have encountered the following question:
We know that amorphous electronic crystals such as amorphous silicon have a bandgap. Can amorphous photonic ...
1
vote
1answer
45 views
Rays in Symmetric Resonator
I'm having some trouble figuring out how to get started on this question:
If I have a symmetric resonator with two concave mirrors of radii $R$ separated by a certain distance, after how many round ...
0
votes
2answers
371 views
Deriving the Poynting Theorem
I am trying to derive the Poynting theorem. So far, I've only been able to narrow down which equations I think I'll need to do so. These are the equations:
Maxwell's Equations:
$$
\nabla\times{\bf E} ...
0
votes
1answer
155 views
Transmission of Gaussian Beam Through Graded-Index Slab
The $ABCD$ matrix of a glass graded-index slab with refractive index $n(y)=n_0(1-\frac{1}{2}\alpha^{2}y^{2})$ and length $d$ is $A=\cos(\alpha d)$, $B=\frac{1}{\alpha}\sin(\alpha d)$, $C=-\alpha ...
1
vote
0answers
121 views
Help With Difficult Deductive Proof [closed]
Suppose we have a Gaussian beam with a complex envelope expressed by the following equation 1:
$$\tag{1}
A_G(x,y,z) = \frac{A_1}{q(z)} e^{-ik \frac{x^2 + y^2}{2q(z)}}
$$
where
$$
q(z) = z+iz_0
$$
...
-4
votes
1answer
70 views
Photonics: Slab As a Lens [closed]
The question can be found here: http://gyazo.com/fc4d26cd35e6ce368ad2a8ed504f1dcc
The refractive index it references can be found here: http://gyazo.com/94fd2f3b5ea7da9226c3acd56b0024c1
I'm not ...
0
votes
1answer
136 views
Where do you get $I_p=\frac{P}{4 \pi r^2} sin \alpha$?
This problem is about color science and it is short but tricky: Where do you get $I_p=\frac{P}{4 \pi r^2} sin \alpha$, where $I_p$ is radiant intensity(color science: radiometric quantities). Look at ...
0
votes
1answer
69 views
What is the new distance for resolution of the images? [closed]
The taillights of an automobile are $1.25\:\rm{m}$ apart. Assume the pupil of a person's eye has a diameter of $5\:\rm{mm}$ and the light has an average wavelength of $604\:\rm{mm}$. At night, on a ...
2
votes
4answers
269 views
How are we able to view an object in a room with bulb..?
This is a very basic question on optics. How are we able to view an object kept in a room with a bulb?
From what I understand, light rays from bulb will hit the object and some colour will be ...
2
votes
1answer
293 views
How to set up a very simple experiment in optics?
This might come across as a very rudimentary question.
My fundamentals of Optics are weak. In the optics chapter of my physics text book I saw diagrams each depicting an object on the left and a lens ...
1
vote
0answers
341 views
Double Slit Problem, Waves and Optics [closed]
Given d(slit separation)= $0.158\:\rm{mm}$, $\lambda _{red}= 665\:\rm{nm}$, $\lambda _{g/y}= 565nm$, L(distance from screen)= $2.24\:\rm{m}$
What is the distance between the third order red and ...
