Index of refraction and electromagnetic radiation

Click For Summary

Homework Help Overview

The discussion revolves around the index of refraction in the context of electromagnetic radiation, specifically examining the relationship between speed, frequency, and wavelength in different media. The original poster presents a problem involving calculations for the index of refraction based on given parameters.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster expresses uncertainty about how to begin solving the problem regarding the index of refraction. Another participant provides a formula for calculating the index of refraction and suggests a similar approach for wavelength ratios, though they express uncertainty about its correctness. The original poster later presents a new problem involving apparent depth and angles, questioning the calculation of actual depth based on the index of refraction.

Discussion Status

Some guidance has been offered regarding the calculation of the index of refraction and the relationship between speed and wavelength. The original poster has also attempted to apply these concepts to a new problem, indicating an ongoing exploration of the topic. There is no explicit consensus on the correctness of the approaches discussed.

Contextual Notes

The original poster references specific values for the speed of light in different media and expresses confusion about the calculations involved in determining actual depth based on apparent depth and angles of incidence.

physicsgal
Messages
164
Reaction score
0
"An electromagnetic radiation has a frequency of 5 x 10^14Hz

a) (wave in vacuum = 600nm)
b) (wave in water = 440 nm)
c) what is the index of refraction of a medium in which the speed of this radiation is 2.54 x 10^8 m/s?"

so given: c = 2.54 x 10^8 m/s
f = 5 x 10^14Hz

required: ni

im not sure where to start on this one. any help will be appreciated.

~Amy
 
Physics news on Phys.org
nevermind, i figured it out! :biggrin:

n = C/v

i don't know how to delete my original post.

~Amy
 
physicsgal said:
"An electromagnetic radiation has a frequency of 5 x 10^14Hz

a) (wave in vacuum = 600nm)
b) (wave in water = 440 nm)
c) what is the index of refraction of a medium in which the speed of this radiation is 2.54 x 10^8 m/s?"

so given: c = 2.54 x 10^8 m/s
f = 5 x 10^14Hz

required: ni

im not sure where to start on this one. any help will be appreciated.

~Amy

I can help with part c, the index of refraction is a ratio between the speed of light in a vacuum to the speed of light in the medium, so if we call the index of refraction n, then

n = (speed of light in vacuum)/(speed of light in medium)

For parts a and b, I think you can do a similar thing with a ratio of wavelengths, but I'm not sure if that's right or not so you may want to wait for someone to give you a more concrete answer about that.
 
thanks dLeet!

im working on another problem if anyone can share some insight..

Someone is on their boat and their eye level is 1 m above the water. and they guess the apparent depth of an object is 2 m below the water surface. the angle of which the person is looking at the object is 45 degrees.

so ni = 1.00029 (air)
nR = 1.33 (water)

so is this just a matter of (2m x 1.33) + 1m = 3.66m actual depth? :confused:

~Amy
 
ok.. did some reading and looks like i was wrong (surprise, surprise).

so i go:
sin 0i = (ni/nR) x sin 45 degrees
sin 0i = (1.00029/1.33) x sin 45 degrees
sin 0i = 0.5318
0i = 32.1 degrees

Dactual = 2.0/tan 32.1 degrees
= 3.18 meters

opinions?

~Amy
 

Similar threads

The refractive index of an unknown liquid
  • · Replies 1 ·
Replies
1
Views
3K
Where Do You Commonly Encounter Electromagnetic Radiation of 5.00 x 10^14 Hz?
  • · Replies 8 ·
Replies
8
Views
4K
Problem involving interference and medium with index n
  • · Replies 1 ·
Replies
1
Views
1K
Calculating Index of Refraction with Wavelength
  • · Replies 1 ·
Replies
1
Views
2K
Multiple-Choice Questions on the Behaviour of Waves and Light 😁
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad Why is Cherenkov radiation blue? And what about refractive index?
  • · Replies 3 ·
Replies
3
Views
2K
Coating Eyeglass Lenses(destructive interference)
  • · Replies 1 ·
Replies
1
Views
4K
Index of Refraction: Calculate ni for 10 cm Attenuation
  • · Replies 2 ·
Replies
2
Views
2K
How Do You Calculate Light Intensity in an Insulating Magnetic Material?
  • · Replies 3 ·
Replies
3
Views
8K
ElectroMagnetic Wave In Liquid Help with Index of Refraction?
  • · Replies 5 ·
Replies
5
Views
2K