# Tagged Questions

Frequency is the rate of repetitive aspect in the amplitude over a given dimension.

722 views

### Why doesn't the speed of the wind have an effect on the apparent frequency?

A boy is standing in front of stationary train. The train blows a horn of $400Hz$ frequency . If the wind is blowing from train to boy at speed at $30m/s$, the apparent frequency of sound heard by the ...
68 views

### Extremely long wavelength electromagnetic radiation

High frequencies are used to eject electrons, because only electrons can really be affected at such a small wavelength scale. But could an electromagnetic wave have such a ridiculously low frequency (...
529 views

### Beat Frequency for Police Radar with Special Relativity

"A radar speed trap operates on a frequency $v_o = 109 Hz$. What is the beat frequency between the transmitted signal and one received after reflection from a car moving at v = 30 m/s toward the radar....
45 views

### Calculating the frequency produced by a rectangular piece of metal

I have a rectangular prism made of steel. Its dimensions are 0.1 cm x 0.2 cm x 12 cm. If I screw one end to a stable object and vibrate the other end. How would I calculate the frequency produced by ...
8k views

### Relation between frequency and intensity of light

I was going through a question in photoelectric effect and it was a true/false which says that the intensity of the incident light gets doubled on doubling the frequency. The answer is given as true ...
157 views

### Damping of not harmonic waves

You pluck a (guitar) string so that you create a wave with harmonic frequency and a wave with not-harmonic frequency. Which one will be heard longer? Why? Or ask it differently: Is the wave with not-...
1k views

### Resultant frequency if 3 harmonic notes (a chord) is played

If I know the frequency of individual notes being played (let's assume D, F# and A), how do I determine the final frequency if they are played (nearly) simultaneously as a chord. To put the problem ...
211 views

### pGRE question on natural line width

The lifetime for the $2p \rightarrow 1s$ transition in hydrogen is $1.6 \times 10^{-9}$ s. The natural line width for the radiation emitted during the transition is approximately... Their solution: ...
466 views

### What is the frequency of a single photon? [duplicate]

What frequency means for a single photon?
456 views

### If wave speed is dependent on medium only, then how to reconcile $v\propto f$?

I have read and learnt in many places that velocity of a wave depends only on the medium through which it travels. It is clear from this that the velocity of a wave doesn't depend on the frequency of ...
57 views

### How do I prove that frequencies that are irrationally related lead to quasi-periodic motion?

Consider the equation: $$\dot{x} = Mx,$$ where M = \begin{pmatrix} i\omega_1 & 0 & \cdots & 0 \\ 0 & i\omega_2 & \cdots & 0 \\ \...
149 views

### Voices of Animals And Humans

What are the differences between voices of animals and humans? (Not by ear but by a program or similar...frequency, other things) Does each animal in each species have a unique voice? Is there a ...
55 views

### What properties affect the color of item?

I already understand how gap bands work and how atoms can absorb/reflect light. I also already understand that rough objects will reflect light differently in comparison to smooth objects, but I do ...
76 views

### One color frequency items

I asked a slightly different question before, but how common are one color frequency items? Many things can reflect many colors of light, but predominantly show one under white light. If they are ...
67 views

### Can a phase array evoke a standing wave at a focal point that has a much higher frequency that the constituent emitted frequencies?

This is a phased array: How can you focus sound? It can focus many waves of weak radio wave or light into a single focal point that's very strong. Now imagine that we delay half of the emitters by ...
116 views

### Why are some elemental materials grey?

How does grey occur in elemental materials such as metals? I believe that grey arises from the simultaneous reflection and absorption of all colors of the spectrum (in different atoms of course), as ...
38 views

### Reflections of objects of a particular color

How can any color reflect the color of light shone upon it? I tested this by shining different colors of light on different objects, and instead of becoming black, it reflected a hazier form of that ...
71 views

### The Color White

How can something that is white reflect all colors? It would have to reflect all frequencies or at least blue green and red, correct? How can a two element compound, such as NaCl reflect all of these ...
109 views

### How can frequency be constant during refraction? [duplicate]

When entering from a rarer to a denser medium, the speed of light decreases.I know that the frequency remains constant.But if frequency is cycles/sec then doesn't that mean more speed will lead to ...
5k views

### Why is it so easy to create audible sound?

Context Why is it so easy to create audible sounds in life with basically anything? Putting your cup of coffee on a table comes with a sound Turning a page of your book comes with a sound Even ...
286 views

### Minimum spread of frequency and wavelength in neodymium laser

What is the equation linking the minimum spread in wavelength and frequency of a pulsed laser, in relation to the lasers pulse time and operational wavelength. For example: If a Neodymium laser ...
90 views

### How are different wavelength components collected by the same detector in a spectrometer?

Let's think, we have a detector array (128x1 and each CMOS detector responds 400 to 1000 nm TSL1401CL that way, each detector has 4.6875 nm interval). Then, basically in a spectrometer a prism reflect ...
42 views

### Question regarding frequency of pendulum while it is stopping

As a pendulum stops, the frequency increases, but of course the pendulum stops. So does the frequency increase so much that it... turns to 0? Or does this have to do with wavelength or speed?
206 views

### Frequency of a photon

in classical physics frequency represents how many cycles in one unit time, but I do not know how we define a frequency for a particle? what does it mean for a particle to have a frequency, the book I ...
317 views

368 views

### Natural frequency of spring-mass system

We can found on internet videos or articles about resonance. For this they for e.g. take a system of two spring and mass in between. When they set force frequency to close to natural frequency. But ...