Blackbody radiation Definition and 114 Threads

Hi, I'm just wondering if Plank suggested that the quantum states and frequencies emitted are quantized, then why do we see a "continuous" spectrum of the BB radiation, not just discrete bands?

I guess this is supposed to be here... I dunno. Anyhoo, I understand this concept intuitively, but why do frequencies have to have integer values? Is that true of all waves, or just electromagnetic waves? Could a wave have 33.43 Hz, for example? :cry: Please explain!

Hi. I am wondering how well the filament in an incandescent light globe follows the basic shape of the classic blackbody temperature/spectrum curves. The reason I ask is that I just set a small science project for a student to measure the voltage and current of a small torch globe (4.8V 0.75A...

In the derivation of plank's equation on blackbody radiation, the radiation within the cavity must form standing waves and thus each frequency has a certain number of possible modes. However, I have no idea why the radiation has to form standing waves. Why does the electric field have to be...

we have a hollow cubical box with sides of length a with perfectly conducting walls, such that the electric field tangential to the surfaces of the walls must be zero. we need to show that the system of standing waves: Ex = Ax*cos(Kx*x)*sin(Ky*y)*sin(Kz*z)*exp(iwt) Ey =...

I am to show Planck's blackbody radiation formula without the stimulated emission: level n is the upper energy level, level m is the lower energy level: N_m B u(\lambda,T)=N_n A \frac{N_n}{N_m}=\frac{B u(\lambda,T)}{A} N_n=ce^{-E_n /kT} N_m=ce^{-E_m /kT} \frac{N_n}{N_m}=e^{-h...

Even by taking low numbers for the surface area and emissivity of the plasma, the radiation would be extremely high due to high temepreatures in magnetic confinement fusion. So how is blackbody radiation countered in magnetic confinement?

Can someone point out any information (derivation or where it comes from) about this equation: S = v\int_0^\infty\phi(\rho,\nu)d\nu \nu is frequency of radiation. \rho(\nu) is radiation energy, v is volume. I'm getting this from Einstein's photoelectric effect paper. Thanks a lot!

What is the rate of energy radiation per unit area of a blackbody at a temperature of 260K ? Where's the tricky part in this question? Surely the answer to this question can't be just stefans constant * T^4 ie. 5.67x10^-8 * 260^4 = 259.105 W/m^2

This is actually a homework question, but its probably better suited for this forum. Gas accreting onto burned-out stars like white dwarfs, neutron stars, and black holes can often be seen in the X-ray part of the EM spectrum, at energies of about 10 keV. What temperature does this suggest...

Can someone help me with this please? B(f) = [(2hf^3)/c^2]{1/[exp (hf/kT) - 1]} - Planck law in terms of frequency. "Derive expressions for B(f) for the cases i. hf << kT, ii. hf >> kT". I've done the first bit, that's just using a Taylor expansion. The second bit is where I'm stuck. In...

Sorry if my physics isn't so good. I only go to High school. Anywayz here is what i understand about blackbody radiation. A blackbody is an object that completely absorbs all the radiation of any wavelength. right. Then blackbody radiation means that a blackbody emitting radiation. Here is what...

when we derive a formula for blackbody radiation, we say that each electromagnetic mode has energy nhf, n is an integer, h is Planck's constant f is the frequency of the radiation. We interpret n as the number of photons per mode. However, a deeper QM analysis involves replacing the...

I'm reading an astronomy textbook, and I'm not sure about some things. The textbook says the EM waves are caused by accelerating charges. I don't understand how this is. I'm not sure, but my memory and intuition tells me that only charges moving in a sinuosidal (can never spell it) manner...