Understanding Wavelength & Frequency: c vs. v

In summary, the two equations are used for different situations. The first equation is used for particles or waves travelling at any velocity, and the second equation is used when v equals c, which is the case for light in a vacuum.
  • #1
Air
203
0
Hello, I confused as there are 2 very similar equation but I do not know when to use each of them. They are:

[itex]f = \frac{v}{\lambda}[/itex] and [itex]f = \frac{c}{\lambda}[/itex].

What is the difference between [itex]c[/itex] and [itex]v[/itex] and when can the appropriate one be used? :confused:
 
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  • #2
Er... one is for a particle or wave at any velocity v, while the other is when v=c (i.e. light in vacuum).

Zz.
 
  • #3
Also, can [itex]c[/itex] also be used when we are considering other source of waves (e.g. electromagnetic spectrum)?
 
  • #4
When I use the word "light", I do mean the EM wave, not just "visible light".

Zz.
 
  • #5
Why do short wavelengths usually penetrate deeper then long wavelengths ?
(I know it has more energy, but I'm looking for more detailed explanation after reading the FAQ).
 
  • #6
GT1 said:
Why do short wavelengths usually penetrate deeper then long wavelengths ?
(I know it has more energy, but I'm looking for more detailed explanation after reading the FAQ).
Said that way it's not true, in general: it depends on material, its surface conditions, and on the range of frequencies; in some cases it could be the opposite.
 
  • #7
lightarrow said:
Said that way it's not true, in general: it depends on material, its surface conditions, and on the range of frequencies; in some cases it could be the opposite.

So if choose randomly 10000 materials only on 50% of the cases the short wavelengths will penetrate deeper ?
 
  • #8
GT1 said:
So if choose randomly 10000 materials only on 50% of the cases the short wavelengths will penetrate deeper ?

Look at one of the most common material on hand - ordinary, transparent glass that you can buy at a store. It allows for the transmission of almost all visible light spectrum, but it doesn't allow UV to penetrate. And UV has a shorter wavelength than visible light.

Your question can't be answered because almost all materials have a finite bandwidth of absorption and/or transmission. This means that there isn't usually a "trend". While some wavelengths smaller than something may get transmitted, other that are smaller or longer may not.

Zz.
 

1. What is the relationship between wavelength and frequency?

Wavelength and frequency are inversely proportional, meaning that as one increases, the other decreases. This is known as the wavelength-frequency relationship, expressed mathematically as c = vλ, where c is the speed of light, v is the frequency, and λ is the wavelength.

2. How does the speed of light factor into wavelength and frequency?

The speed of light, denoted as c, is a constant value in the universe. It is the maximum possible speed at which all energy, including light, can travel. Wavelength and frequency are both affected by the speed of light, as they are used to calculate it.

3. What is the unit of measurement for wavelength and frequency?

Wavelength is typically measured in meters (m) or nanometers (nm), while frequency is measured in hertz (Hz) or cycles per second (s-1). However, in some cases, other units such as kilometers or megahertz may be used.

4. How are wavelength and frequency related to the electromagnetic spectrum?

Wavelength and frequency are important components of the electromagnetic spectrum, which is the range of all possible wavelengths and frequencies of electromagnetic radiation. The electromagnetic spectrum includes all types of light, from radio waves with long wavelengths and low frequencies, to gamma rays with short wavelengths and high frequencies.

5. What are some real-world applications of understanding wavelength and frequency?

Understanding wavelength and frequency is crucial in many fields, such as telecommunications, astronomy, and medical imaging. It allows us to transmit and receive signals, study the properties of light and other electromagnetic radiation, and use technologies like MRI machines to visualize internal structures of the human body.

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