0.30 s after seeing a puff of smoke rise from the starter pistol the sound of the firing of the pistol is heard by the track tim
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Answer:
3 photons
Explanation:
The energy of a photon E can be calculated using this formula:
Where corresponds to Plank constant (6.626070x10^-34Js),
is the speed of light in the vacuum (299792458m/s) and
is the wavelength of the photon(in this case 800nm).
Tranform the units
The band Gap is 4eV, divide the band gap between the energy of the photon:
Rounding to the next integrer: 3.
Three photons are the minimum to equal or exceed the band gap.