Amplitude? [ENDORSED]

$c=\lambda v$

BeylemZ-1B
Posts: 72
Joined: Thu Jul 25, 2019 12:17 am

Amplitude?

Can someone explain to me in more detail what amplitude is? I was not quite sure when it was explained in class.

Brian Tangsombatvisit 1C
Posts: 103
Joined: Sat Aug 17, 2019 12:15 am

Re: Amplitude?  [ENDORSED]

Amplitude measures the height of the crest of the wave from the midline. It's a measurement of length, so its unit is meters. Waves with tall crests have large amplitudes.
Don't confuse amplitude with wavelength, which is the distance from one crest to another.

Ruby Richter 2L
Posts: 88
Joined: Thu Jul 25, 2019 12:17 am

Re: Amplitude?

I think amplitude is essentially the height of a wave from the average value or the rest position. It's independent from wavelength and frequency and determines the intensity of light. I think a good way of visualizing it is picturing the difference between the extreme values on the wave.

Ryan 1K
Posts: 75
Joined: Fri Aug 09, 2019 12:15 am

Re: Amplitude?

Does that mean that a higher amplitude corresponds to a higher intensity of light?

Sydney Pell 2E
Posts: 85
Joined: Wed Sep 11, 2019 12:17 am

Re: Amplitude?

Yes, the amplitude corresponds directly with the intensity of light. So, having a high amplitude would mean the light has high intensity. On the other hand, wavelength (distance between between the peaks) tells you what type of light it is.

Posts: 87
Joined: Wed Sep 18, 2019 12:21 am

Re: Amplitude?

Amplitude of light wave I basically a measure or how tall the peaks are and how low the dips are in the wave.

ShastaB4C
Posts: 79
Joined: Thu Sep 26, 2019 12:18 am

Re: Amplitude?

So is it correct to conclude that the equation c = wavelength x frequency is just relating to their inverse relationship and the light’s identity (e.g. red visible light, UV light, etc) while the amplitude just means that light’s intensity; therefore amplitude isn’t involved in the equation?

Jordan Ziegler 2J
Posts: 59
Joined: Sat Aug 17, 2019 12:15 am

Re: Amplitude?

Is there an equation that defines amplitude as a variable of wavelength and/or frequency?

I discussed with my TA that amplitude changes when frequency changes to maintain the constant c (speed of light), but it would be helpful if someone could further elaborate or explain. I'm still not quite understanding how light intensity varies with light frequency.

805394719
Posts: 88
Joined: Wed Sep 11, 2019 12:16 am

Re: Amplitude?

I am not sure if they are interchangeable since, in the photoelectric effect, the incoming light has to have sufficient energy to remove an electron from the metal surface. The experiments have shown that increasing the intensity of the light that has a long wavelength does not have any effect on the removal of an electron. Because wavelength and frequency are always equal to the speed of light, you can think of it as low-frequency light does not remove an electron. Since increasing the intensity still did not remove an electron, it should mean that the intensity did not have any effect on the frequency of the light.