Refractive index Definition and 280 Threads

  1. T

    Constant thickness lens varying refractive index

    Homework Statement Homework EquationsThe Attempt at a Solution my initial approach was to just imagine the light rays leaving the focal point and emerging parrallel but then the result had no dependence on thickness how to tackle this problem how does the thickness even factor in
  2. T

    What is the relationship between critical angle and negative refractive index?

    Homework Statement [/B] Homework Equations Snell's Law: n1sin(i)=n2sin(r) Critical angle=sininverse(n1/n2) [**only works when n2>n1] If a light beam is incident at an interface of 2 mediums(with r.i n1 and n2) at an angle greater than the critical angle,the interface acts as a...
  3. R

    Refractive index as a function of the concentration of a sugar solution

    We recently performed an experiment with the idea to find refractive index of medium (water) as a function of wavelength of light. We then added some sugar to see how the refractive index changes with concentration of sugar solution. We got the following graphs. Are the relationships actually...
  4. S

    Exploring the Relationship between Concentration & Refractive Index

    < Mentor Note -- two threads merged and new user reminded not to multiple-post threads at the PF > i'm experimenting about refractive index and i can't figure out the relationship between concentration of the solution and Refractive index. What i found about this is that RI is connected to...
  5. C

    Phase shift of e.m. wave through a glass plate

    Homework Statement Consider a glass plate of refraction index n and thickness ## \Delta x ## placed between a point monochromatic source S and an observer O, as in picture. (a) Prove that, if absorption from the plate is neglegible, then the effect on the wave received by O is the add of a...
  6. pallab

    The dielectric constant of water is 80, but refractive index

    The dielectric constant of water is 80, however its refractive index is 1 ·33 invalidating the expression n*n=ε. why?
  7. C

    Path of light in a medium with increasing refractive index

    Homework Statement A medium has a refractive index, ##n(y)=n_0 \sqrt{1+y/a}## which increases along y. Assume ##n_0## and ##a## are constants and always positive. If a light beam enters horizontally along y, through (0,0), find the curve the path of the light ray takes. Homework Equations ##F...
  8. G

    Electronically Change Material Refractive Index

    Hi, How do I electronically change material refractive index? Is Kerr effect the right way? Is there any good material that have Kerr effect, that can be used in modern gadgets? Is there any gadget/device that use this kind of material? Thanks:) Regards, Grheee
  9. A

    How to find the speed of light practically?

    Currently, I'm doing the CREST award for physics, and my topic is about different methods of finding out the refractive index of a medium. I have already tested out few ways, and now i am thinking about a method where a formula n=c/v will be used(n-refractive index, c-speed of light in vacuum...
  10. sounouhid

    Thin film refractive index determination

    Hi every one , I want to find the refractive index of a thin film using it's reflectance and transmittance spectrum is there a way to do that ? thank you for advance
  11. RabbitWho

    Finding the angle of refraction

    Homework Statement The refractive index of diamond is 2.42. A ray of light passing from the inside of a diamond into air makes an angle of incidence of 20 degrees. Find the angle of refraction. Homework Equations n = refractive index aNd = 2.42 (my book said the speed of light in a vacuum and...
  12. RabbitWho

    Finding apparent depth real depth and refractive index

    Homework Statement refractive index = 1.33 (water) real depth = 10m Homework Equations refractive index = real depth divided by apparent depth The Attempt at a Solution I'm going to call apparent depth X 1.33 = 10/x So I multiply 10/x by 10 so that i have x and 1.33 x 10 is 13.3... that's...
  13. ChrisVer

    A TRT Electron Radiation: Transition Between Refractive Indices

    How can the radiation of electrons in the TRT be described/explained with transition between media of different refractive indices?
  14. D

    Do the Relative Permittivity and Refractive Index of Water Match Up?

    Many textbooks and online sources give the relative permittivity of water as about 80 and the refractive index as 1.33. If you use the definition of refractive index to find the speed of light in water, you will find v = c/n ~ 2.56e8 m/s. However, if you use the equation to find the speed of...
  15. F

    Dry vs. Humid Air: Refractive Index Differences

    Homework Statement This is from a old exam[/B] Humid air has a different refractive index than dry air: in the microwave region n'(dry) > n'(humid) and n''(dry) < n''(humid), where n' and n'' denote the real and imaginary part of the refractive index, respectively. How are the effects asked for...
  16. J

    What is the group refractive index for a monochromatic wave in a laser cavity?

    Homework Statement .[/B] I am attempting to determine the group refractive index of a laser cavity at it's resonance frequency. Homework Equations .[/B] \begin{align*} \frac{2\omega n L}{c} &= 2m\pi \end{align*} \begin{align*} n_g &= n + \omega \frac{dn}{d\omega} \end{align*} 3. The attempt...
  17. J

    Is it possible to find refractive index from diffraction?

    Homework Statement I am trying to find the refractive index nylon (fishing line) , however when I used a laser onto the fishing line (nylon) it looked like it diffracted. Homework Equations I am able to find the diffraction if that was what it was showing, however I don't know how to calculate...
  18. Martel_lu

    I Bandgap Energy and refractive index

    The statement that the higher the bandgap energy Eg, the lower the refractive index of material is confusing me. If I start from two equations. Eq1: Eg=hc/lamda_g Eq2: lamda=lamda_0/n Higher Eg means lower lamda_g. It means in order to have the light in semiconductor material with wavelength...
  19. TheSodesa

    How Does an Electromagnetic Wave Propagate in Glass?

    Homework Statement A harmonic EM-wave is propagating in glass in the +x-direction. The refractive index of the glass ##n = 1.4##. The wave number of the wave ##k = 30 \ rad/m##. The magnetic portion of the wave is parallel to the y-axis and its amplitude ##H_0 = 0.10A/m##. At ##t=0## and ##x =...
  20. G

    Total internal reflection, refractive index, optical fibres

    How does the claddibg with lower refractive index reduce the light loss from the core? Thank you.
  21. G

    Why Does Snell's Law Give Incorrect Results When Using Certain Formulas?

    At the start of the chapter the book told me to use this formula to find refractive index: N= Sin(i)/Sin(r) How ever later in the section they showed me to use this formula when three quantities are given : NxSin(i)=NxSin(r) I tried apply the same method to a question, it gave me a wrong...
  22. vetgirl1990

    Index of refraction for converging lens

    Homework Statement A thin converging lens has radii of curvature of R1=9cm and R2=-11cm. Assume its focal points F1 and F2 are 5cm from the center of the lens. Determine its index of refraction. Homework Equations Len's Makers equation: 1/f = (n2 - n1 / n1) (1/R1 - 1/R2) The Attempt at a...
  23. Physicist50

    Solar Cells & Refractive Index

    Hi there, I have recently been researching in depth solar cells/panels, the parameters of their efficiency and the photoelectric effect in general, specifically how different wavelengths of light affect it. My research has yielded a few facts; that the efficiency of standard silicon solar cells...
  24. M

    Optical and electrical bandwidth "outside" air

    My questions is about the conversion of a range of wavelengths in Hz, such as for an optical filter, in a medium different from air. Since the refractive index n is higher than 1, (let's say n=1.5) and than the value of c is almost 2x108 m/s, also the equation in the link below has to be...
  25. G

    Refractive Index of BEC: Exploring Its Potential for X Rays and Gamma Rays

    Does a BEC still have a very large refractive index for X Ray's and gamma rays?
  26. Yen Pham

    Explain the value of refractive index of water?

    I have studied about the formula of refractive index which is: . That means in the case of water which have μ =1 (approximate) and ε = 81, then n should be 9. But why we often use the value n = 1.33 for water ? Who can explain for me? I don't think the above formula is wrong, of course!
  27. K

    How Does Glass Thickness Affect Refractive Index Calculation?

    Homework Statement Old photographic plates were made of glass with a lightsensitive emulsion on the front surface. This emulsion was somewhat transparent. When a bright point source is focused on the front of the plate, the developed photograph will show a halo around the image of the spot. If...
  28. Anithadhruvbud

    Can refractive index of a material be less than unity?

    And what is the difference between refractive index and absolute refractive index? Why do we use relate two absolute refractive index to find the refractive index of a particular material say we need to find refractive index of water with respect to ice.and why do we always put the higher value...
  29. E

    Newton's Rings using refractive index of water

    Hi I am currently looking at Newtons Rings, i have changed my refractive index to water (distilled), i have found the rings and they seem to be as aspected except they are extremely faint barely readable infact would anyone know a cause or soulation to this?
  30. W

    Refractive index for magnetic material

    hi, I have studied the general expression for metamaterial as n=√(εμ) for dielectric relative permeability is one and we have n=√ε, but what would be the refractive index for magnetic material , by seeing symmetry I figure out as n=√μ will it be valid and we have Lorentz model for dielectric...
  31. N

    How does Band Gap and Refractive index relate to Wavelength?

    Homework Statement Nobel prize for physics for blue laser diode using Gallium Nitride with band gap of 3.4 eV and a refractive index of 2.429. Explain how these parameters determine at what wavelength a Gallium Nitride semiconductor will laser at. Homework Equations E=\frac{hc}{\lambda}...
  32. Vaibhav Sahu

    Snell's law for an interface with variable refractive index

    Consider an interface along x-axis which separates two media. The medium below y = 0 is air or vacuum and light is incident from this medium onto the surface. The refractive index of the medium above y = 0 varies with x as some function of x : μ = f(x). Does the Snell's law still hold good ?? If...
  33. I

    Q: Refractive index in phase contrast microscopy

    If you're using a phase contrast microscope and the refractive index of the medium is equal to the refractive index of the cell, what are you able to see? I guessed that you wouldn't see anything, but apparently that's wrong. The only options are membranes, vesicles, the nucleus, pigment...
  34. P

    Two Prisms connected by a material of refractive index n

    Homework Statement The prisms have a refractive index ##n_1=1.3## at wavelength ##\lambda=300nm## and are connected by a material with refractive index ##n_2##. What is the refractive index ##n_2## so that light of wavelength ##>\lambda## follow path 2, and light at ##<\lambda## follow path 3...
  35. A

    Identification of a ratio using Refractive indices (RESOLVED)

    Homework Statement I need to find the X of two substances using only the data found in lab. Which is: nmixture=1.4156 nbutan-2-one=1.3787 ntoluene=1.4970 For the mixture, I don't know what X (the mole fraction) is. That is what I must find out. Homework Equations nmixture= (Xbutan-2-one...
  36. S

    Solve Refractive Index Homework: Order of Interference & n

    Homework Statement I have set up an experiment such that microwave is converged and beamed to a polymer slab and the reflected wave is measured. I have recorded angle of incidences from 15 to 90 degree and I found out that at 80 degrees, the output is the highest, while at 45 and 85 degrees...
  37. A

    Mathematical descriptions of opacity

    Hi https://en.wikipedia.org/wiki/Mathematical_descriptions_of_opacity it is mentioned above that "in non attenuating media, the refractive index and angular wavenumber are related by: A complex refractive index can therefore be defined in terms of the complex angular wavenumber defined...
  38. A

    Refractive Index: Variations & Formula Proof

    Hi 1)Does refractive index varies when we are dealing with different waves? for example the refractive index for a typical glass is 1.5 when a visible light passes through it. Does it the same for x rays? 2) there is a complex formula which describes the refractive index: n = 1- δ - iβ. how is...
  39. G

    Refractive index in the ultraviolet region

    When white light is refracted in a prism, we can see that blue color has the strongest refraction: the shorter the wavelength, the strongest the refraction. But the electromagnetic radiation with very short wavelength (X-rays) are not refracted by an amorphous solid such as glass: most part of...
  40. C

    IOR Uncertainty Quantification for PIV/LDV Measurements

    Hello All, I am running some experiments using Particle Image Velocimetry and Laser Doppler Velocimetry techniques. There is a slight mismatch in the Refractive Index of the fluid and my model (Approximately 5% difference) which is creating some uncertainty in my measurements. I was wondering...
  41. H

    Dependence of Radiation Absorption on Refractive Index

    I am reading the text 'thermal radiation heat transfer' by Howell et al. (2011). In it they describe normal spectral emission by an isothermal volume element dV as 4\pi \kappa_\lambda I_{\lambda b}(S)dVd\lambda where \kappa_{\lambda} is the absorption coefficient and I_{\lambda b} is the...
  42. S

    Ordinary and extraordinary refractive index

    Homework Statement From an uniaxial crystal, a 0.7 mm thick plate is cut out in a way that the optical axis is parallel to the surface. A light falls perpendicular to the surface (circular polarization) with 500 nm. After the crossing of the plate, the light has elliptical polarization and the...
  43. Samurai44

    Calculating Critical Angle: Relative vs. Absolute Refractive Index

    Greetings, Do we use Absloute refractive index when finding crtical angle ? if it was two mediums ( not vacuum or air) how would i calculate the critical angle ? I mean i get confused when I find relative refractive index because sometimes i get sine inverse greater than 1 which give no...
  44. Robsta

    Interferometer to measure refractive index of a gas

    Homework Statement I've uploaded a diagram showing a two beam interferometer that can be used to monitor changes of refractive index in a gas cell. it is illuminated with monochromatic light of wavelength λ. The light is linearly horizontally polarised. The two polarizing beam splitters (PBS)...
  45. C

    Light Refraction on the Surface of a Sphere

    Hello All, Using Snell's Law, it is pretty obvious how to calculate the angle of refraction when both index of refractions are known. My question is how would I apply this to a 3 dimensional situation, such as light refraction in a sphere? Since there are two angles in relation to the normal...
  46. J

    Help with radius of curvature and refractive index of lens

    Hi, I am a first time poster and I am completely lost with this question. Any help would be greatly appreciated Filling the space between a contact lens and the cornea is a small quantity of liquid of refractive index of 1.336. Assuming the refractive index of the lens material is 1.490 find...
  47. R

    How to control the refractive index?

    How can I control the refractive index on a material, I mean on what depends the refractive index? Because I am trying to create like a controlable light diffuser mechanism. Thanks and regards.
  48. fissionary

    Polarization and refractive index

    Is there any relation between refractive index and polarization?
  49. S

    Does the refractive index law change according to the medium

    The refrative index law should be sine(i)/sine(r) but in the answer he done the opposite. I included the answer in the bottom of the question.
  50. AdityaDev

    Changing electric field and refractive index

    I am learning sky wave propagation and in my book, a relation between refractive index, dielectric constant and electro field strength is given. \mu=\mu_0\sqrt{1-\frac{Ne^2}{\epsilon_0m\omega^2}} Is this a form of Kerr opto-electric effect? How do you get this expression? If you think I cannot...
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