Physics 1.3 Photons Flashcards
What is a photon?
A photon is a packet or “quantum” of electromagnetic waves.
What are the types of waves on the electromagnetic spectrum, in order of wavelength?
Radio (>0.1m)
Microwave (0.1m-1mm)
Infrared (1mm-700nm)
Visible light (700nm-400nm)
Ultraviolet (400nm-1nm)
X-Rays (10nm-0.001nm)
Gamma Rays (<1nm)
What is the equation for the energy of a photon? What does this mean?
E=hf
This means that the energy of a photon is directly proportional to its frequency.
where;
E is the energy of the photon in joules [J]
h is the Planck Constant in joule seconds [Js]
f is the frequency of the photon in hertz [Hz]
The value of the Planck Constant is 6.63 * 10^-34Js.
What is the mass of a photon? What does this mean?
0kg
This means photons travel at the speed of light, c.
3.00 * 10^8 ms^-1
What is the wave equation?
c=fλ
where;
c is the speed of light in metres per second [ms^-1]
λ is the wavelength in metres [m]
f is the frequency of the photon in hertz [Hz]
What is the combined equation for the energy of a photon and the wave equation?
E = hc/λ
where;
E is the energy of a photon in joules [J]
c is the speed of light in metres per second [ms^-1]
λ is the wavelength in metres [m]
h is the Planck Constant in joule seconds [Js]
