# Planck's constant

1. Sep 12, 2006

### Sheyr

According to quantum mechanics the energy of radiation is equal to multiple Planck's constant : E = h * v, where "v" is the radiation frequency.

Since there is no limit to frequency, what is the energy of radiation of frequency 1/2 Hz?

S.

2. Sep 12, 2006

### neutrino

h/2 J.101010

3. Sep 12, 2006

### selfAdjoint

Staff Emeritus
Where h is expressed in SI units; Planck's constant has dimensions $$ML^2T^{-1}$$, so that would be $$Kg m^2 sec^{-1}$$.

4. Sep 14, 2006

### Sheyr

Thank you. I thought before that the energy must be procuct of integer number of 'h'.

5. Sep 14, 2006

### neutrino

Energy is emitted or absorbed in integer multiples of $$h\nu$$.

6. Sep 26, 2006

### Sheyr

If this is true, than the oscillator working on the frequency ½ Hz can’t emit the radiation. Or am I wrong?

7. Sep 26, 2006

### neutrino

n*h*(nu)...it's the 'n' that's restricted to integers, not nu.

8. Nov 11, 2006

### selfAdjoint

Staff Emeritus
If you look at those units for h, $$ML^2T^{-1}$$, you see that it does not represent a quantum of energy, but of action. This is why energy can increase or decrease by continuous amounts, it is only the action, e dt, that is quantized.

9. Nov 12, 2006

### sneez

if we assume photon can have the largest wavelength of the size of the universe and assume universe is 10^26m

by forumla c=lamb*nu

you can compute smallest nu and energy E=H*nu

: Photon is an energy emitted from internal atom/molecule transitions. There is no other way i know of photon can be created.

10. Nov 13, 2006

### Chaos' lil bro Order

What about electron/positron pair annihilation, this creates gamma rays.

11. Nov 13, 2006

### sneez

"What about electron/positron pair annihilation, this creates gamma rays"

Very good. I forgot about this.

12. Jan 25, 2007

### whatta

I thought any change of charged particle trajectory should generate photon.

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