1.3 photons
- Created by: maddie
- Created on: 29-11-12 09:32
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- photons
- Light - small part of spectrum of electromagnetic (EM) waves, our eyes cannt detect other parts.
- In vaccum all EM waves travel at speed of light, c (3.0x1068 ms). Wavelength = c/ frequency,f.
- waveleght expressed in nanometers, 1nm = 10^-9 m.
- EM waves - electric and magnetic waves whcih travel together and vibrate they are ...
- at right angles to each other and the direction they are travelling
- in phase with each other , reach peak at same time.
- EM waves are emitted by a charged particle when it loses energy when ...
- fast moving electron stops, slows down or change direction
- electron in shell of atom moves to different shell of lower energy
- EM waves emitted as short burst of waves leaving source in different direction. Each burst is a packet of EM waves - a PHOTON
- photon theory established by einstein to expalin photoelectrcity - emission of electrons from metal surface when light directed at surface
- Einstein assumed energy, E, of a photons depends on its frequency: E=hf, where h - placks constant, 6.63 x10^-34Js.
- photon theory established by einstein to expalin photoelectrcity - emission of electrons from metal surface when light directed at surface
- laser beam consists of photons of same frequency
- power of laser beam - energy/sec transfered by photons. Power of beam = nhf where...
- f = frequency of photons, n = number of photons passing fixed point per sec, h = plancks constant
- power of laser beam - energy/sec transfered by photons. Power of beam = nhf where...
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