Wavelength Definition and 1000 Threads

E=mc^2 and E=hf. In Special Relativity, how can y=h/p be derived from E=hf?

Is there any lower limit on the frequency of electromagnetic radiation? I imagine that beyond a certain frequency it becomes impossible to detect, but is there anything in the maxwell equations that establishes a maximum wavelength (besides the limits of the size of the universe)? Thanks

Homework Statement In his presentation of the de Broglie wavelength and the wave/particle duality, my quantum prof. has an exercise: "Find the de Broglie wavelength of a molecular vibration. Do quantum or classical laws apply?" Homework Equations wavelength = h/(momentum) ...

1. Astronomers on Earth observe a feature at 442 nm in the spectrum of a distant quasar. However, it is known that this feature corresponds to 581 nm in the rest frame of the quasar. Calculate the speed of the quasar. Enter your answer as a fraction of the speed of light, positive if the quasar...

The maximum wavelength for blackboby radiation is .29/Temperature. Is the average wavelenght 1.84 times the maximum for all temperatures?

I've gotten curious about how the human eye's sensitivity to long wavelengths drops off. What's the longest wavelength anybody has ever seen? I know there is nonzero (but very low) sensitivity to 800+ nm light, but does anybody know the extreme long wavelength limit of human vision?

Homework Statement Electron and positron each have a kinetic energy of 220 keV even when far apart. Homework Equations The Attempt at a Solution I have no idea. My book says the answer 1.46 MeV, 8.49 x 10^-13 m but I don't know how to get that.

Hi, Why are mass and wavelength are inversely proportional?

I've been searching on this topic for the past 10 minutes and then realized it'll be better just asking someone about it. Anyway yeah, the question is, are there any specific equations that will give me the wavelength when I give it the colour values? I saw some sites where each colour in the...

Why are short wavelengths (of e.m. radiation say) required for observing the location of a small particle? Classically, I could imagine sending a wave train of light (or a photon) of different frequencies onto an atom in free space. Providing the electrons in the energy levels of the atom can...

Hello, I've always wondered about the "relativity" of the De Broglie wavelength. The wavelength depends on the momentum of the specific thing we are observing, thus on different frames of reference(F.O.R from now on :P) we might get different answers. I have been looking through the web to...

Homework Statement Parallel beam of "cold" neutrons in the x-axis, with energy 0.1eV strikes a slit system in y-z plane. Slits are parallel to the y-axis 1 micron apart. What will be the distance between the detector at x=20m which records the highest flux of neutrons, and the closest one...

Homework Statement Two of the wavelengths emitted by a hydrogen atom are 9.50×10-8 m and 4.65×10-6 m. What are the m and n values for the first wavelength? Homework Equations E = -13.6eV/n2 E = -13.6eV/(m2 - n2) restriction:m > n E = hf f = c/λ 1 eV = 1.6 x 10-19J The Attempt at...

I am creating this wavelength chart (attached). I was told to use Compton's formula; I got this: (6.626068 × (10^(-34))) / (1.1542e+42 * 299 792 458) = 1.91493535 × 10-84 Apparently, it is substantially off scale. I was then told to try de Broglie wave. Wikipedia only shows relations...

It there a smallest possible wavelength? And if there is, what is that wavelength?

it has been a while. i need to know which wavelength is bigger FM radio or Am radio?

Homework Statement Calculate the de Broglie wavelength of an oxygen molecule (molecular mass 32)in air at room temperture. Homework Equations P = h/ \lambda P= mv E= hv = 1/2mv^{2} = P^{2}/(2m)The Attempt at a Solution hv = 1/2mv^{2} h = 1/2mv If v = P/m then h = mp/2m so p= 2h This...

can anyone tell me the meaning of frequency and wavelength of photon.what exactly it indicates?As it is particle then how it can have frequency and wavelength?frequecy is charaterstics of wave.

Could electromagnetic wavelength be used as a legitimate distance pattern? I mean is it OK to exchange geometrical length with physical wavelength? For example, given a bundle of light rays following geodesics in empty space, can the length between a given pair of geodesics be equivalent to a...

What kind of electromagnetic radiation can carry more information?. I mean, what is the relation between shorter or longer wavelength and the information that can go within. I wonder how the dynamics of this process works, considering that sound waves also can carry information, as well every...

I can work out the wavelengths fine, but I am unsure of the answer to the second part, any help would be much appreciated

Homework Statement what is the physical significance of wavelength (not the definition)? Homework Equations suppose, in photodetectors (like avalanche or p-i-n photo diodes) incident light having more wavelength, penetrates more in the diode (particularly in depletion region : )...

Can anyone tell me what frequency and Wavelength Radar and Sonar work in. I think Radar have a frequency of 300giga hertz (UHF), wavelength 0.1 Sonar is somewhere between wavelength 100k - 10k metres, frequency 3k - 30k hertz. Please help me thanks,

Homework Statement The wavelength of an electron is 4.4 × 10−7 m. How fast is it moving? The Planck’s con- stant is 6.62607 × 10−34 J · s . Answer in units of m/s. 013 (part 2 of 2) 10.0 points If the electron has a speed of 9 × 106 m/s, what is its wavelength? Answer in units of m...

hi, my exam is tomorrow and I really need to understand this. Imagine a region of constant gravitational field, directed "downwards". There is a photon traveling in this downward direction. There are two observers, A and B. At t=0, they do not have any relative velocity. However, B is fixed...

Just curious, what is the longest wavelength we can currently observe with our instruments, & are there are good sources for future (even if just theoretical) projects at longer wavelengths (future projects do no have to be based on Earth)?

I'm doing OCR A-Level Physics, and in my textbook it states "They (Penzias and Wilson) made a calculation to find the temperature of the source of the radio waves, which had a maximum intensity at wavelength 1.1 cm, and found it to be 2.7K". This was all good and well, until I answered a...

Homework Statement A car is traveling at 30m/s in still air. the frequency of the siren on the car is 600hz. The velocity of sound in still air is 330 m/s. what is the wavelength of the sound waves a)directly in front of the car b)directly behind the car What is the frequency of the...

Homework Statement Find the wavelength of the radiation emitted when a hydrogen atom makes a transition from the n = 6 to the n = 3 state. Give answer in µm. Homework Equations z^2 / n^2 x 13.6ev delta E = E2 - E1 = hv The Attempt at a...

As is well known, Planck's radiation law for the distribution function of blackbody radiation used a then new concept of energy quanta in order to describe experimental data. The distribution functions formulated by Wilhelm Wien and Lord Rayleigh, describing the same phenomena, were...

Homework Statement A surface of a substance has a work function of 2.24 eV. (a) What is the maximum kinetic energy of ejected electrons if the incident radiation is of wavelength 419 nm? eV (b) What is the threshold wavelength for this surface? nm Homework Equations E=hf...

Hey guys and girls, I'm having a hard time trying to start this problem. I think I have an idea of what to do to start it, but I'd like someone to verify it for me: Homework Statement A mass, m = 5.50kg hangs from a cord around a light pulley. The distance between point P and the pulley...

i think its to do with huygens sources?

I am trying to work out the real component of the wavelength of microwaves in copper. I am given n2=er=-i sigma/eo omega where n is the refactive index er is the relative permitivity eo is the permitivity of free space i = sqrt(-1) omega is the frequency of the microwave sigma is the...

Homework Statement Microwaves of wavelength 2.80 cm fall on a slit and the central maximum at a distance of 1.0 m from the slit is found to have a half-width (i. e. distance from middle of central maximum to first minimum) of 0.67 m. Find the width of the slit.

Homework Statement A extent ray of light with wavelength \lambda _0=632.8 nm incide over a screen containing 2 horizontal parallel slits very thin and separated by a distance of 0.2 mm. We observe an interferance over a screen at 1.00 meter away from the screen containing the horizontal...

Homework Statement -a pipe closed at one end resonates with a turning fork at a length of 25cm. The next resonant length is 75cm. The air temperature is 11.6C. What is the wavelength of the sound produced by the turning fork. Homework Equations 1st harmonic: lambda = 4 * L 3rd...

Why do the chlorophyll in land plants absorb primarily in the blue and red wavelengths, http://en.wikipedia.org/wiki/File:Solar_Spectrum.png" ? Isn't more energy available in 500nm green light vs 700nm red light? E =\frac{hc}{\lambda}

Homework Statement (1) A sound wave is traveling through air medium, if the medium is replaced by water, how that will affect the wavelength, frequency and speed of the wave ? (2) If the temperature of the air changed, how that will affect the wavelength, frequency and speed of the wave ...

When an EM wave goes into say a denser medium and its velocity is decreased how does its wavelength and frequency change? I read that the frequency remains constant but the wavelength changes. Is this true? If so does that mean the wave gets compressed when it enters a denser medium. Does the...

Homework Statement At what wavelength does a 100mW laser deliver 3.5 x 1017 photons in one second? h (plancks) = 6.626x 10^-34 c = 3 x 10^8 Homework Equations E = hf ==> E = hc / n (wavelength) ==> n = hc / E Power = Energy / Time The Attempt at a Solution Energy = Power *...

Homework Statement How can you know "the difference between the two lasing energy levels?" Homework Equations n(lambda) = 2(pi)r E = hf mvr = n(h-bar) The Attempt at a Solution no clue

1. A monochromatic laser is exciting hydrogen atoms from the n = 2 state to the n = 5 state. What is the wavelength of the laser? 2. frequency = f = delta E / h lambda = c/f 3. First, is the following approach valid: I find delta E by computing E5 - E2, where En = n2h2/8mL2...

Is there a way to calculate the wavelength, frequency or energy (per photon) of the virtual photons that charges exchange to account for the Coulomb force? This is assuming that it's always the same wavelength, of course.

1. The magnetic field of an electromagnetic wave in a vacuum is B_z= ( 3.0 uT )*sin(( 1.00*107)x - omega*t) , where x is in m and t is in s. What is the wavelength and frequency of this magnetic wave? What is the amplitude of the E field? 2. wavelength = 2pi/k frequency = f = 1/T =...

Homework Statement Young's fringes, produced by monochromatic laser light passing through slits 0.60mm apart, are viewed on a screen. The distance accrose 20 fringe spacings on the screen is 58mm. When the screen is moved 0.80m away from the slits, the distance across 20 fringe spacings...

Homework Statement Young's fringes, produced by monochromatic laser light passing through slits 0.60mm apart, are viewed on a screen. The distance accrose 20 fringe spacings on the screen is 58mm. When the screen is moved 0.80m away from the slits, the distance across 20 fringe spacings...

Homework Statement A double-slit interference pattern is observed on a screen 1.0m behind two slits placed on 0.3mm apart. Ten bright fringes span a distance of 1.65cm. What is the wavelength of the light? Homework Equations Since we're looking at bright fringes: (m+1/2)\lambda =...

How can I get the wavelength of a single proton if its kinetic energy is equal to its internal energy?

i have been working on this question for quite a while. no help on google, or my textbook at all. A hydrogen atom in its ground state is excited to the n=5 level. It then makes a transition directly to the n=2 level before returning to the ground state. A) What are the wavelengths of the...