Chapter 5.1 Flashcards
Ole Romer
Studied the movements of the moons of Jupiter in the 1670s. Discovered irregularities in the moon’s orbital periods which depended on the position of earth in its orbit. Discovered that when the earth was closes to Jupiter, it was 17 minutes late by the time the earth was furthest away from Jupiter. Light must travel at a finite speed.
James Clerk Maxwell
Introduces the concept that electricity and magnetism are two components of the same physical phenomenon. Summarized the behavior of electric fields and magnetic fields in four equations.
How do electric and magnetic fields interact?
A change in the motion of a charged particle causes a changing electric field, which causes a changing magnetic field and so on.
What is a good analogy for an electromagnetic field
A drop of water dropping in a still pond. Electric and magnetic waves are created due to the movement of charged particles.
velocity of light-
frequency times wavelength
Why is the frequency and wavelength of light always known?
Because the speed of light in a vacuum is constant.
What is the range of visible light?
From violet (380nm to red 750 nm)
Albert Einsten
In 1905 he explained the photoelectric affect in which subatomic particles called electrons are emitted when surfaces are illuminated by electromagnetic radiation greater than a certain frequency. Showed that the rate of electrons emitted depends only on the amount of incoming light and the speed of the electrons depends only on the frequency on incoming radiation.
Wavelenth of light =
speed of light/ frequency
Energy of light=
Planks constant times frequency of light.
Wave
A disturbance moving along a surface or passing through space or a medium
Vacuum
A region of space devoid of matter. In quantum mechanics a perfect vacuum has physical properties
Energy
The conserved quantity that gives objects and systems the ability to do work
Kinetic Energy
The energy of an object that resullts form its motions
Thermal Energy
The energy that resides in the random motion of atoms, molecules, and particles, by which we measure their temperature.
Electric Force
The force exerted on electrically charged particles such as protons and electrons, arising from their electrical charges.
Magnetic Force
The force exerted on electrically charged particles such as protons and electrons, arising from their motion.
Electric Field
A field that can exert as force on a charged object, whether at rest or moving.
Magnetic Field
A field can exert a force on a moving electric charge.
Electromagnetic Wave
A wave consisting of oscillations in the electric-field strength and the magnetic-field strength.
Medium
The substance that a wave, such as light, travels through.
Amplitude
The Maximum deviation from its undisturbed or relaxed position. Related to the brightness of light.
Wavelength
The distance on a wave between two adjacent points having identical characteristics. Related to the energy of light. Units is meters. wavelength =speed/frequency
Frequency
The number of times per second that a periodic process occurs Unit is hertz
Hertz
A unit of frequency equivalent to cycles per second.
Spectrum
Waves sorted by wavelength
Nanometer
One billionth of a meter. Used for the wavelength of visible light.
Electromagnetic Spectrum
The spectrum made up of all possible frequencies or wavelengths of electromagnetic radiation, ranging from gamma rays through radio waves
Gamma Ray
Electromagnetic radiation with higher frequency, higher photon energy, and shorter wavelengths that all other types of electromagnetic radiation. Can pierce dense b one
X-Ray
Can pierce the skin, organs, tissues, but not dense bone.
Infrared Radiation
Wavelengths lower than red light. Used by predictors to detect pray. Think heat on the stove.
Micron
One millionth of a meter. Used for infrared light.
Microwave radiation
Used in microwaves. Between infrared and radiowaves.
Radio wave
Longest region of the spectrum. Used for radios.
Photon
Called quantum of light. A discrete unit or particle of electromagnetic radiation. Equal to planck’s constant h times frequency.
Quantum Mechanics
The branch of physics that deals with the quarantined and probabilistic behavior of atoms ans subatomic particles.
Ultraviolet Radiation
Electromagnetic Radiation having frequencies and photon energies greater than visible light but below x rays. Used by pollinators to detect flowing plants.
Light as a Particle
Can travel long distances in a straight line. Proposed by newton
Light as a wave.
Slit experiments by Thomas Young study the duality of light. Behaves light a particle in some respects but like a wave in others.
