Last modified on 28 March 2013, at 15:51

Physics Course/Radiation/Black Body Radiation

Black Body Radiation

It has been observed that any conductor when conducts current exhibit the following phenomenons

1. Change in Temperture
2. Radiate Light of Radiant Heat Energy

This is known as Black Body Radiation

Experiment

Connect voltage source with a conductor in a closed loop . Measured the value of current at diferent frequency . The graph of I - f shows that

Observations

Radiant Heat energy is a wave travels at speed v = λ f at all frequencies f less than fo carries an energy level E = m v2. At fo, Radiant Heat energy reaches its peak value and travels with speed equals to speed of light in the vaccum v = C = 3 x 108 carries an energy level E = h fo. At any frequencies greater than fo, Radiant Heat energy remain the same for all frequency f > fo carries an energy level E = h nfo

Frequency Speed Wavelength Energy
f < fo v = λ f λ = $\frac{v}{f}$ E = m v2
f = fo v = C = λ fo λ = $\frac{C}{fo}$ E = h fo
f > fo v = C = λ nfo λ = $\frac{C}{nfo}$ E = h nfo

Summary

Frequency Speed Wavelength Energy
f < fo v = λ f λ = $\frac{v}{f}$ E = m v2
f = fo v = C = λ fo λ = $\frac{C}{fo}$ E = h fo
f > fo v = C = λ nfo λ = $\frac{C}{nfo}$ E = h nfo
1. Every conductor has a maximum absorb energy at Threshold frequency , fo
2. Light Wave of Radiant Heat Energy radiates from any current conducting material has a Particle Wave Duality Characteristic . Sometimes it behaves like Particle, sometimes it behaves like Wave.
3. Energy is quantized for f > fo and can only have an integer multiply by frequency E = h f
4. Short Wavelength calculated $\lambda = \frac{C}{f}$

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