What is the energy of a microwave photon of wavelenght 1.00mm?
Please help me! I just dont get it . thank u!!
2007-07-02 04:54:07 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Physics
OK, E = h x f. (E = energy, h = plank constant, f = frequency)
Now, we know the photon has wavelength 1x10^-3 meters (1mm). and that the speed of light (including microwaves) is 3x10^8 meters. Also, c = f x w. (c = wave speed, w = wavelength).
So, 3x10^8 = f x 1x10-3. Therefore, by rearranging the formula, you get the frequency to be 3x10^11.
If we go back to the first formula, E = h x f, then the energy is found by using E = 6.63x10^-34 x 3x10^11
E= 1.989x10^-22 J.
2007-07-02 05:06:55 · answer #1 · answered by Anonymous · 0⤊ 0⤋
The energy of a photon is given by the Einstein's equation:
E = hv
where h is planck's constant (6.64 x 10^-34) and v is the frequency of the photon emitted.. Frequency can also be expressed as c/y where c is the speed of light (since it's a photon) and y is the wavelength..
so E = hc/y
just put the wavelength as 0.001 m and c as 3x10^8 and you'll get the answer in SI (joule, that is).
2007-07-02 05:01:40 · answer #2 · answered by sloth 3 · 0⤊ 0⤋
Frequency = Velocity / wavelength = 3 x 10^10 cm / 0.1 = 3 x 10^11
Energy = Planck's Constant x Frequency
= 6.626 x 10^-34 x 3 x 10^11 = 19.878 x 10^-23 Joules
= 1.988 x 10^- 22 Joules.
2007-07-02 05:09:16 · answer #3 · answered by Swamy 7 · 0⤊ 0⤋
energy formula of a photon is hc/wavelength
h is planks constant h=4.136x10-15 eV-sec.
and c is velocity of light
hence as h and c are constant hc is a constant of value 1240ev-nm
lenght is 1 mm i.e 10^6 nm
hence energy is 1.24 x 10^9 ev
u can work even in joules
2007-07-02 05:02:52 · answer #4 · answered by stiffmeister 2 · 0⤊ 0⤋
This is a two stepper.
First convert from wavelength to frequency
(wave length)*(frequency)= speed of light
Then Energy = H * frequency, where H is Planck's constant.
2007-07-02 04:59:18 · answer #5 · answered by cattbarf 7 · 1⤊ 0⤋
E=h*(c/wavelength)
=6.626*10^-34*(3*10^8/10^-3)
=6.626*10^-34(3*10^11)
=1.9878*10^-22J
=1.2423*10^-3eV
2007-07-02 05:01:28 · answer #6 · answered by Anonymous · 0⤊ 0⤋
E = hc / lambda
Where h is Planck's constant, and lambda is wavelength measured in meters.
2007-07-02 04:59:49 · answer #7 · answered by Brian L 7 · 0⤊ 0⤋
go to this site:
http://prola.aps.org/abstract/PRA/v44/i6/pR3445_1
2007-07-02 04:56:36 · answer #8 · answered by Anonymous · 0⤊ 0⤋