Chpt 4 Flashcards
Who first discovered photons?
Ancient Greeks
A photon is also known as what?
Electromagnetic energy
Two examples of electromagnetic energy
light
x-rays
What is the smallest quantity of any electromagnetic radiation?
photon
What is pictured as a small bundle of energy or Quantum that travels through space at the speed of light?
photon
(T/F) An X-ray photon is a quantum of electromagnetic energy
True
Do EM waves require a medium to travel?
No, they can travel in a vacuum
What other form can EM waves travel in?
As a sine wave
Four characteristics of a sine wave
Speed, wavelength, frequency, amplitude
What is the top of the wave called? The bottom?
Crest, Trough
What is the speed of light?
3 x 10^8 m/s
What is the distance between two successive points on a wave?
wavelength
A wavelength is measured in? (2)
Angstroms or meters
One angstrom is how many meters?
1 A = 10^-10
What is the intensity of the wave defined by its maximal height or is one-half the range from the crest to the valley?
Amplitude
What is the number of cycles per second?
Frequency
What is frequency measured in?
cycles/sec or Hertz (Hz)
1 Hz is how many cycles per second
1 Hz = 1 cycle/sec
Wavelength and frequency have what relationship and why?
Inversely proportional, because in the equation c is constant
EM energy is measured in what?
Electron volts (eV)
The energy of 1 electron passing through a potential difference of 1 volt is what?
1 eV
1 eV = ? joules?
1.6 x 10^-19 joules
EM radiation needs what eV to have the ability to ionize
10 eV or higher
When an atom gains or loses an electron
Ionization
