Powerpoint Info Flashcards
Explain Maxwells idea about waves
Maxwell (1873), proposed that visible light consists of electromagnetic waves.
What is electromagnetic radiation?
Electromagnetic radiation is the emission and transmission of energy in the form of electromagnetic waves.
What is the speed of light in a vacuum?
3.00×10^8 m⁄s
what is a wavelength of a wave?
distance per cycle
What is frequency?
cycles per second
What is the equation for electromagnetic radiation?
c = (lmada) x (v) where lambda is wavelength v is frequency c is speed of light
What is the typical unit of wavelength? How do you convert it to meters to cancel out with speed of light value?
Typically, in nm multiply by (10^9nm/m)
what does the amplitude tell you about the wave?
what does high amplitude and low amplitude mean about brightness/dimness of the wave?
What are the regions of the electromagnetic spectrum in order from highest to lowest?
radio, microwave, infrared, visible, ultraviolet, x-ray, and gamma ray
What is the electromagentic spectrum?
The electromagnetic spectrum is the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies.
What are the different behaviors of waves and particles?
Waves experience refraction in water. Waves experience diffraction when they come across a hole or opening and bend in a curved geometric shape.
Particles experience no refraction when the trajectory hits the water. When a beam of particles hits an opening, they shine through
What is constructive and deconstructive interference?
Constructive interference occurs when the maxima of two waves add together (the two waves are in phase), so that the amplitude of the resulting wave is equal to the sum of the individual amplitudes. … The nodes of the final wave occur at the same locations as the nodes of the individual waves.
Destructive interference occurs when the maxima of two waves are 180 degrees out of phase: a positive displacement of one wave is cancelled exactly by a negative displacement of the other wave. The amplitude of the resulting wave is zero. … The dark regions occur whenever the waves destructively interfere.
What is the diffraction patter produced when light passes through 2 adjacent slits?
There are portions of the waves in phase and out of phase
Waves in phase make a brighter spot and waves out of phase make a darker spot
What is a blackbody?
What is blackbody radiation?
A blackbody is a theoretical or model body which absorbs all radiation falling on it, reflecting or transmitting none.
Black-body radiation is the thermal electromagnetic radiation within or surrounding a body in thermodynamic equilibrium with its environment, emitted by a black body (an idealized opaque, non-reflective body). It has a specific spectrum of wavelengths, inversely related to intensity that depend only on the body’s temperature, which is assumed for the sake of calculations and theory to be uniform and constant
What kind of radiation is blackbody radiation also known as and how is it used to study space?
Also known as thermal radiation
Although planets and stars are neither in thermal equilibrium with their surroundings nor perfect black bodies, black-body radiation is used as a first approximation for the energy they emit.[6] Black holes are near-perfect black bodies, in the sense that they absorb all the radiation that falls on them. It has been proposed that they emit black-body radiation (called Hawking radiation), with a temperature that depends on the mass of the black hole.
What is the blackbody radiation problem?
They could not understand the surprising results they continued to get from heating surfaces that absorb all frequencies of light that hit them, otherwise known as black bodies.
energy must be transferred in quanta
Quantum, in physics, discrete natural unit, or packet, of energy, charge, angular momentum, or other physical property
What did Max Plank’s Nobel Prize in 1918 show? What year did he do his work?
Work was around 1900
Nobel Prize for the discovery of energy quanta
Planck’s constant: 6.626 x 10^-34 Jxs
How did Planck’s work in thermodynamics lead to the discovery of blackbody radiation?
Explain the concept of energy quanta and Planck’s calculations
To explain the colors of hot glowing matter, he proposed that energy is radiated in very minute and discrete quantized amounts or packets, rather than in a continuous unbroken wave.
Planck called the packets of energy quanta and he was able to determine that the energy of each quantum is equal to the frequency of the radiation multiplied by a universal constant that he derived, now known as Planck’s constant. This number, expressed in terms of erg-seconds, measures the energy of an individual quantum.
What is the photoelectric effect?
Who discovered it?
Albert Einstein Nobel Prize in 1921
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons.
What are the takeaways from the photoelectric effect?
Light waves are also stream of quantized particles - photons
The energy of a photon is given by
E = (h)(v)
h is Planck’s constant
v is the frequency
How did the study of blackbody radiation and the photoelectric effect generally contributed to the discovery of quantum mechanics?
Blackbody radiation is a cornerstone in the study of quantum mechanics. Blackbody radiation is a theoretical concept in quantum mechanics in which a material or substance completely absorbs all frequencies of light. Because of the laws of thermodynamics, this ideal body must also re-emit as much light as it absorbs.
Black body radiation could not be explained with classical electrodynamics. Max Planck derived a formula assuming that light was absorbed and re-emitted by the black body according to the Einstein relation: E = hf.
In 1905, Albert Einstein explained the photoelectric effect by postulating that light, or more generally all electromagnetic radiation, can be divided into a finite number of “energy quanta” that are localized points in space.
The idea that each photon had to consist of energy in terms of quanta was a remarkable achievement; it effectively solved the problem of black-body radiation attaining infinite energy, which occurred in theory if light were to be explained only in terms of waves.
What wavelengths does continuous (white light) contain?
What wavelengths does emission spectra contain?
Continuous (white light) spectra contain all wavelengths of visible light
Emission spectra only contain specific wavelengths of light
What is Bohr’s Model of the Atom (1913)?
What year is the nobel prize won in?
Nobel Prize 1922
- e- can only have specific (quantized) energy values
- light is emitted as e- moves from one energy level to a lower energy level; each level is:
