Special relativity Flashcards
What are the four limitations of the wave model of light demonstrated through the photoelectric effect?
- If light were a wave there would be a time delay for enough energy to build up to free photoelectrons.
- If light were a wave even a low frequency wave should eventually build up enough energy to break a photoelectron free.
- The threshold frequency varies between metals.
- Shining brighter (higher intensity) light produces more electrons not more energetic electrons.
List the colours of the visible light spectrum from smallest wavelength to longest wavelength
Violet, blue, green, yellow, orange, red
What is the principle of relativity?
The laws of physics are the same in all inertial frames of reference
What is the speed of light in a vacuum?
Approximately 3 times 10 to the power of 8 metres per second
What does e=mc^2 represent?
Energy equals mass times the speed of light squared. This shows the equivalence of mass and energy.
What is time dilation?
A phenomenon where time passes slower for an object in motion compared to one at rest.
What is length contraction?
A phenomenon where the length of an object moving at high speeds appears shorter across the
What is length contraction?
A phenomenon where the length of an object moving at high speeds appears shorter across the
What does the stopping voltage indicate?
How much work must be done to stop the most energetic photoelectrons.
How does frequency of light affect the photoelectrons?
High frequency means higher energy/velocity of the photoelectrons. The higher the frequency the more negative the stopping voltage becomes.
How does intensity affect photoelectrons?
Higher intensity of light increases the number of photoelectrons that are released. The lower the light intensity the lower the maximum current.
What is Planck’s constant in Js?
6.63 X 10^-34 Js
What is Planck’s constant in eV?
4.14 X 10^-15
