Frequencies Definition and 395 Threads

Hello All, I have two questions regarding mixing of frequencies. I heard that there is a difference between two waves that simply ‘add’ mathematically, and two waves that are ‘multiplied’ mathematically. If I have two frequencies, say 10Hz and 11Hz and I add the waves together so that they...

If you konw the voltage and current as a function of time of a spark acorss a sparkgap, can you calculate the frequencies? If so, how?

Hi to everyone. I have heard that we usually prefer to modulate signals at high frequencies so the wave length is small compared to the length of the antenna. Is there any rule or equation that implies this requirement?

If you happen to see microwaves... Scientists Take Step Toward Invisibility http://www.nytimes.com/2006/10/20/science/20cloak.html?hp&ex=1161316800&en=cd2cdec26f18ae3a&ei=5094&partner=homepage See also: http://www.ee.duke.edu/~drsmith/cloaking.html

Hey guys, long time no see. I was flipping through a book about black holes and gravity when i saw a chart about different frequencies and I came up with a little thought that would be nice to have explained. Why is it that lower frequencies (radio/microwave) and higher (x-ray/gamma ray) can...

What is the relationship between Quantum Physics and electromagnetic frequencies?

Hello folks, I would like to know whether or not the cavity axial-mode frequencies have any influence on the frequency output of the laser beam. I suppose that the atomic transition from excited state to ground state is the only occurrence responsible for the wavelength, whereas the axial-mode...

Is it possible? It is said that the human being can hear from a dynamic range of 20 hz to 20,000 hz. Apparently, the human eye is not able to detect audible frequencies. I have a question though... Can we see audible frequencies? Our are eyes capable of catching them? If a drop of...

This is very important. Can someone tell the dependency for the resonance frequencies of bubbles? i.e if know a bubble's diameter, the surface tension, the liquid and the gas' densities how do I calculate the sound wave frequencies that causes a resonance in a bubble. I have Landau's formula...

Evening, Ive been having some trouble with questions about fundamental frequencies and labelling nodes and anti nodes in an air column. for example :a tuning fork is placed above a glass tube and then the sound of the air column is adjusted by raising or lowering the glass tube in the...

I looked at a spectrogram of our sun several months ago. It contained a whole plethora of frequencies. It appeared that there were many thousands of frequencies in the visible spectrum alone. When scientists investigate redshifts, do they look at a specific frequency, or do they just...

Hi, here’s my question. If I make an oscillator that resonates at 6kHz and a second oscillator that resonates at 5kHz, the magnetic field produced by the coils of the two oscillators would be 1000Hz (please correct me here if I have made an incorrect assumption). If I have a 1000Hz signal that I...

Hi, just out of curiosity, i heard about a new electron gun (if that's the proper term) using a laser pulsing at about 3.333 x 10e14 Hz to increase the frequency at which the electrons are emitted. How does the laser reach such pulsing frequencies? Thanks.

what is the highest attainable frequencie by an oscillator circuit? :confused:

This is a question that has been bugging me for quite and long time and I have been searching on the Internet, but having no luck. So, why does lower frequency sound pass through materials much easier then higher? Thanks, Rich

When i was a kid i read the first book on hitscock the 3 investigators Bob Pete and Jupiter the castle of terror where everytime they would go to the castle they would be terrify, in the end an old movie star would have been hiding in the castle and scare people by using a certain no audible...

How could you tell if you had missed one of the natural frequencies when you were finding natural frequencies above the fundamental? thnx a lot

I was wondering if there is any info on the frequencies of individual galaxies?

Hello, i found one question really difficult and I can't solve it. Please help. Six hens are observed over a period of 20 days and the number of eggs laid each day is summarised in the following table: No. of eggs: 3 4 5 6 No. of days: 2 2 10 6 This can be considered as a...

Ok, I am working with problems dealing with Speed=(lambda) (frequency). I have a question in determining whether I am solving these correctly. I sometimes get confused as what the wavelength is. 1. A longitudinal wave with a frequency of 25.0Hz travels along a coil spring. If the distance...

Hi. I'm having some trouble understanding resonance. I was reading about how ears work on howstuffworks.com, and it noted that the ear picks up different frequencies basically because little hairs inside the ear resonate at different freqencies. It said that this is also the concept behind...

Hi Everyone, I just joined the forum and would like to extend a big hello to everyone! I had a look around the forum and it's a treasure trove of information. Congrats to everyone... I have a question that my father keeps asking and I don't know the answer to this one: Why don't the...

I am stumped on how exactly to do this. I have the function: T(s) = 7/s(s^2+6s+58) I need to change this to T(iω) and i being a complex root. This creates: T(iω) = 7/(ωi*(ω^2+6iω+58)) I know I need to plot this function and find out where omega peaks and this will be my resonant...

Hi there ! I have a question : does a mechanical system generating a lower frequency when excited with a hig frequency exists ? In this case, would it be possible to start stimulated processes of emission of a lower frequency from a high frequency ? Then, we could imagine a kind of laser not...

We all know that light speed in a vacuum is constant and travels 9.8 X 1018 meters in a year. Now since light travels in waves instead of a straight line, if the wave was then uncurved, it would cover more distance than when it was in its original state. Of course different lights have...

I'm currently studying vibrations and frequencies. I know that humans can hear from a range of 20Hz-20kHz. I was wondering if sound energy could reach a frequency where it was no longer really sound. Is this possible?

A variable capacitor with a range from 10 to 365 p is used with a coil to form a variable frequency LC circuit t0 tune the input to a radio. a. What ratio of max and min frequencies may be obtained with such capcitor. I used that \omega=\frac 1{\sqrt(LC)} to get the ratio of max to min...

I'm not sure if this is the right forum for it, but I had a few questions about how color vision works. I know that mixtures of pure colors look like other pure colors. For example, some mixture of pure (monochromatic) green and blue looks like pure yellow. So for a given color, are there an...

I don't know a whole lot about quantum mechanics and there is something that dosen't make sense to me. An atom absorbes radiation in only certin frequencies. Do these frequencies have to be exact? Can they vary over a small range like say 1.000 to 1.001 or do they have to be perfectly exact...

Does it make any sense to ask at what frequencies stings vibrate? If so, is there a source that provides information along these lines?

Hi, short question. What would be the effect of 2 sources both transmitting 2 different frequencies if placed in a way that forms an interference pattern. ie. 2 aerials places parallel X meters apart transmitting in the same direction at 2 different frequencies per aerial. Sorry if i...

does the brain send out signals or frequencies. I believe i recall hearing about something like beta waves perhaps it was. Someone know of this?

I am having a problem finding where to start. The problem is this: A loudspeaker at the orgin emits sound waves on a day where the speed of sound is 340 m/s. A crest of the wave simultaneously passes listeners at the (x,y) coordinates (40m,0m) and (0m,30m). What are the lowest two frequencies of...

Hello, I've been thinking about why (elementary) transformer efficiency drops drastically at very low frequencies. I know hysteresis effects play a major role in reducing efficiency at high frequencies, but why low? I realize that as we reduce the frequency of the emf, we're making the...

to begin, a few things i am not a physicist or physics student i am open to corrections and answers via both my email and thread i am a new user and do not know if this is the correct place to post this string theory states that every thing is composed of "strings" running at a certain...

The lowest tone to resonate in a close-end pipe of length L is 200Hz. Which is of the following frequencies will not resonate in the pipe? 400Hz 600Hz 1000Hz 1400Hz Anyone know where I should start on this?

Two different simple harmonic oscillators have the same natural frequency (f=2.80 Hz) when they are on the surface of the Earth. The first oscillator is a vertical spring and mass, the second is a pendulum. If both systems are moved to the surface of the moon (g=1.67 m/s2), what is the new...

Okay, this may sound like a dumb question, but if i were to create a wireless signal with a frequency of red light for example, how come i would not see red light... or would i? Is this a difference caused by real and virtual photons?

it is often said that the rich sounds produced by e.g. a guitar is due to the string vibrating at several different frequencies at once.. does this mean that there is both the fundamental frequency and several overtones present at the same time.. if so, I don't get it.. how can there be more...

topic of BH ringing freq. came up in "Loop Quantum Gravity" thread in SringBraneLQG forum. I'm starting this thread here in hopes that some regulars here (Labguy, Nereid, others?) can shed additional light. From a pedagogical or intuitive point of view it seems to bring the topic closer to...

How can an astronomer recognize a double star from the characteristic frequencies of the light that reaches him from its member stars? I have looked and looked in my textbook but I cannot come up with the answer to this one. Thank you! mmfoley

How can an astronomer recognize a double star from the characteristic frequencies of the light that reaches him from its member stars? I have looked and looked in my textbook but I cannot come up with the answer to this one. Thank you! mmfoley

Light is found in different frequencies, which accounts for all of the energy types we find such as visible light, x-rays, gamma rays, infrared, radio waves, etc. Do magnetic fields also exist in different frequency ranges? If so, what are some methods that could be used to manipulate...

Let's present a scale of frequencies of light. For initial we’ll take frequency of visible light. Here particle / wave duality is shown fifty- fifty. At increase or decrease of frequency this proportion is broken. Frequency increasing. Properties of a particle...

If one can mix certain colors of the visible spectrum to produce other colors, is it possible to mix frequencies from other parts of the electromagnetic spectrum to produce visible colors?