# Tag Info

## New answers tagged frequency

0

When you got a rotation movement, the change of the angle per time is characterized by the angular frequency $\omega=\frac{d\phi}{dt}$. You can assign every rotation movement to a oscillation. This is often done in books to introduce the mathematical concepts of oscillation. Rotations are easy to understand at that moment. Then you can assign pointers to ...

0

One cycle involves $\sin(x)$ where $x$ goes from zero to $360$ degrees, or zero to $2\pi$ radians. The frequency is cycles per second, and the angular frequency which is to say, degrees/second or radians/second. Radians are a more "natural" unit, degrees are arbitrary (based on Babylonian base sixty arithmetic)

1

The Fresnel equations are derived by matching the electric and magnetic fields of the incident, reflected and transmitted waves at the interface. In this process only the instantaneous value of the fields is used not their rate of change with time. This means the frequency of the wave simply doesn't enter the calculation. However, as a comment notes, the ...

-1

Theoretically speaking, you can use Doppler effect to change the frequency of light... But the change is so tiny that it is of practically no use at low speeds... I'm pretty sure there is no other direct way... Hope this helps!!!

1

There is a general way to increase the frequency of light. It is Doppler Effect. You can keep the observer (target for photoelectrons) and move the source of light towards it. But it is not practical, because you will need very high relative velocity to have any considerable change in the frequency.

2

Frequency of the emitted light depends on the nature of the source. Eg: Incandescent -- depends on the temperature of the material Discharge Tubes -- depends on the characteristic spectrum of the gas

0

I am also pretty much unclear about it. But thing of fire, fire at the bottom or where the fire starts, the acceleration of charged particles is more, which means the frequency is also more and wavelength is short. As, $$E=hv$$ Where E is total energy, h is Planck's constant and v is frequency. The acceleration of charged particles is more as the ...

3

You cannot simplify the effects of EM radiation on biological systems to simply $E=hf$ because different materials absorb or transmit different frequencies preferentially. $E=hf$ tells us the energy per photon, but it doesn't tell us how much is absorbed by any particular type of cell. It also doesn't tell us the intensity of the radiation (energy per ...

0

Bandwidth is the most important thing here. In order to send information you need distinguishable pulses, which can be interpreted as 0 oder 1 for no pulse or pulse respectively. The optical bandwidth and pulse duration are related by the time bandwidth product $$0.44 < \Delta t \Delta f \approx \frac{c}{\lambda^2} \Delta t \Delta \lambda$$ Note the ...

0

The rate emission of photons is a measure of total power: 100 photons per second vs 1,000,000,000 photons per second. The individual photon emitters are, for example, electrons being driven back and forth in a radio circuit: the photons are quanta of radio waves, with the frequency of the oscillator circuit setting the energy of each photon by Planck's ...

0

This is a phenomenon called dispersion of light. White light is a mixture of all colours which get separated when they pass through a prism. The refractive index or simply for lay usage the angle at which light bends when it enters from one medium to another depends on the wavelength of light. So the colours are not newly created, but they are just ...

6

When light enters glass (or another transparent material), its frequency stays the same and its wavelength changes. In a comment, you say that you are using "color" to mean "wavelength". Well, I think you are using the word "color" incorrectly. According to a normal definition of "color", the color of light does not change when it enters glass. But the ...

2

The wineglass does vibrate in a transverse mode, deforming from a circle to a elliptical elongating first in one direction then the perpendicular direction repeatedly. Here is a short video and a peak at the classic article ”In Vino Veritas – A study of wineglass acoustics” A.P French, Am. J. Phys., Vol.51, No. 8, August 1983.

1

Yes, this is indeed possible. The most common application of this would be television.

1

Just to add to Jim: Any of the three can be used to to retrieve message by transmitting (a) only the side bands (b) only one side band (c) only carrier frequency. Even, sometimes usually due to economic reasons only the upper or lower side bands of an AM is transmitted. The three waves of different frequency are not incorporated into single carrier ...

1

There are plenty of references made to the frequency. The gravitational waves that were detected swept up in frequency and amplitude from an undetectable level at a few tens of Hz to abut 150 Hz as the black holes merged. This is known as a "chirp". Gravitational wave sources might have a variety of frequencies. For binary systems, the principle ...

0

we know that frequency is inversely proportional to the wavelength of light by the formula $f=\frac 1\lambda$' So frequency will increase if wavelength is decreased.

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Mainstream physics has described the microcosm of molecules, atoms, elementary particles with the theory of quantum mechanics, and in particular the quantum mechanical standard model of elementary particles, and it has a mathematical form, a Lagrangian. . In this Lagrangian the elementary particles, including the photon, are entered as point particles with ...

1

I think CuriousOne's comment provides most of the answers to your question, but for completeness I'll expand it into an answer. Light is described by quantum field theory and can only be fully understood in this context. We sometimes talk about photons and sometimes talk about light rays, but these are only approximations. As a general principle light ...

4

Or are the frequencies detected the same as the resonant frequencies of the bars used? The LIGO detectors, which measured the waves, do not use bar detectors; they use interferometers. Bar detectors have been used for decades, but they have not been sensitive enough to make actual detections. They are necessarily very short, which reduces the effect ...

18

Have a look at an announcement from LIGO where they describe the experiment. The first plot shows the frequencies detected. The original waves are redshifted. Estimated source parameters for GW150914. We report the median value as well as the range of the 90% credible interval. Masses are measured in the source frame; to convert masses to detector ...

0

Phonons are the particle-like analogue of normal modes. So yes, the frequencies are the same.

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I'm only answering part of your question, but your question (1) has already been answered on the site. but everywhere I keep reading they always refer to this bridge between 'microwave cesium radiation' and optical radiation. I don't fully understand the connection. The optical frequency comb is generated by a laser source generating periodic very ...

1

When a wave moves from one medium with different speeds, the frequency remains unchanged, and the wavelength changes to accommodate the new speed.

-2

The wavelength cannot be changed by the motion of the observer, but the frequency and the speed of the waves (relative to the observer) do change: http://physics.bu.edu/~redner/211-sp06/class19/class19_doppler.html "Let's say you, the observer, now move toward the source with velocity vO. You encounter more waves per unit time than you did before. ...

4

How is this one frequency creating all these modes? The laser output frequency is determined by two things: The gain spectrum and the cavity mode structure. In your example, the gain spectrum is the blue line. This is determined by the difference in energy levels, like you said. But the energy levels are not so narrow as you might think. Sometimes what ...

1

Yes(at least measurably). According to generalized uncertainty principle, the Planck length(1.616199e-35m)is the the shortest measurable length(within a factor of 10). So that can be the shortest wavelength possible. Which gives maximum frequency to be 6.187356e34 Hz. Plank length - Wikipedia

3

No. There is an approximate limit to the wavelengths (spectrum) emitted by an object of a given temperature: in fact, before quantum mechanics, there was a problem called the "UV catastrophe" where calculations of the spectrum suggested there should be infinite power in the shortest wavelengths; QM could explain away this problem, and it was one of the early ...

1

Your transfer function appears to be representing the relative displacement between $M_1$ and $M_2$ as a result of an input excitation, $W$, presumably a force. This simplified linear model is often used to express the dynamics of an automotive suspension system where $M_1$ is the mass of the vehicle and $M_2$ is the mass of the suspension mechanism and ...

3

There is no theoretical physical limit on the wavelength, though there are some practical limits on the generation of very long wavelengths and their detection. To generate a long wavelength requires an aerial of roughly one wavelength in size. The accelerated expansion of the universe due to dark energy means the size of the observable universe is tending ...

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