Notes in 02 Electromagnetic Radiation and Quantum Phenomena

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Published	01/09/2024	electron volt{{c1::Ek of electron after its accelerated from rest through potential differece of 1 Volt}}
Published	01/09/2024	how to calculate the electron volt {{c1::E = Q × VE = energy(J)Q = charge(C)V  = potential difference(V)1eV = 1.6 × 10-19 × 1 = 1.6 × 10-19J}}
Published	01/09/2024	how to convert energy → electron volt{{c1::1 eV = 1.60 × 10-19Jnote the charge of a proton is 1.60 × 10-19. so all thats done is charge × 1V to get en…
Published	01/09/2024	Lowest energy level in electrons is known as{{c1::ground level/state}}
Published	01/09/2024	Electrons emit {{c1::photons}} as they move down energy levels
Published	01/09/2024	Describe when an electron is excited{{c1::its in energy level higher than ground state}}
Published	01/09/2024	Where do electrons exist?{{c1::electrons only exist in well defined(discrete) energy levels}}
Published	01/09/2024	Excitation{{c1::movement of electron to higher energy level}}
Published	01/09/2024	energy of photon given out in relaxation/de-excitation{{c1::difference in energies of electrons between two levels of transition}}
Published	01/09/2024	Formula for energy of photon emitted after relaxation/de-excitation{{c1::ΔE = E1 - E2 = hf ⇒ hc/λΔE = change in energy(J)E1 - E2 = change in energy of…
Published	01/09/2024	How to find frequency/wavelength of photon emitted in electron transition{{c1::E = E1 - E2}}{{c1::convert eV to Joules( x 1.6-19)}}{{c1::E = hf (find …
Published	01/09/2024	ionisation{{c1::electron removed from atom}}
Published	01/09/2024	ionisation energy{{c1::energy needed to remove an electron from atom}}
Published	01/09/2024	How do fluorescent tubes work{{c1::high voltage applied across mercury vapour}}{{c2::accelerates fast moving electrons → ionise mercury atoms → produc…
Published	01/09/2024	what is fluorescent tube made of{{c1::mercury vapour}}{{c1::inner phosphor coating}}
Published	01/09/2024	photoelectric effect{{c1::shine radiation of high enough freq. onto metal surface, electrons emitted}}
Published	01/09/2024	explain how photoelectric effect takes place{{c1::metals contain "free electrons" able to move}}{{c1::UV radiation hits metal surface → free electrons…
Published	01/09/2024	electrons emitted during photoelectric effect{{c1::photoelectrons}}
Published	01/09/2024	conclusions of photoelectric effect{{c1::radiation frequency > threshold frequency → electrons emitted}}{{c1::Ek of photons increase with frequency…
Published	01/09/2024	threshold freq.{{c1::minimum frequency required for emission of photoelectrons}}
Published	01/09/2024	intensity of radiation {{c1::number of photons/amount of energy hitting area per second}}
Published	01/09/2024	purpose of photoelectric effect{{c1::light can't just act as a wave}}
Published	01/09/2024	kinetic energy of photoelectrons increase with {{c1::frequency}}
Published	01/09/2024	who was first to suggest EM waves can only be released in discrete packets, or quanta{{c1::Max Plank's}}
Published	01/09/2024	Max Plank was first to suggest {{c1::EM waves can only be released in discrete packets,or quantas}}
Published	01/09/2024	formula for energy of photon{{c1::\(E = hf = \frac{hc}{\lambda}\)}}{{c1::whereE = enrgy of photonh = planks constantc = speed of lightλ = wavelength}}
Published	01/09/2024	what did Einstein suggest after Max Plank{{c1::EM waves(and the energy they carry) can only exist in discrete packets called photons}}
Published	01/09/2024	demonstration of the photoelectric effect{{c1::zinc plate attached to top of electroscope(box containing metal with strip of gold)}}{{c2::zinc is -ve …
Published	01/09/2024	why can't visible light be used in photoelectric effect{{c1::freq. of visible light isn't high enough}}
Published	01/09/2024	work function energy (φ){{c1::energy required by electron to break bonds holding it before leaving metal surface}}
Published	01/09/2024	work function energy's value depends on {{c1::metal}}
Published	01/09/2024	if energy gained from photon > work function energy{{c1::electron can be emitted}}
Published	01/09/2024	if energy gained from photon < work function energy{{c1::electron will shake, then release energy as another photon}}
Published	01/09/2024	condition for electron to be released in photoelectric effect{{c1::hf ≥ φ}}
Published	01/09/2024	threshold frequency formula{{c1::\(f_o = \frac{\phi}{h}\)}}{{c1::wherefo = threshold frequencyφ = work function energyh = planks constant}}
Published	01/09/2024	formula for maximum kinetic energy of photoelectron{{c1::\(E_k = hf - \phi\)}}{{c1::whereEk = maximum kinetic energyh = planks constantf = frequencyφ …
Published	01/09/2024	explain why the max. Ek of photoelectron is \(E_k = hf - \phi\){{c1::electrons absorbs hf from one photon}}{{c1::electron requires work func…
Published	01/09/2024	another form of \(E_k = hf - \phi\){{c1::sub in \(E_k\) as \(\frac{1}{2}mv^2\)}}{{c1::\(\frac{1}{2}mv^2 = hf - \phi\)}}
Published	01/09/2024	why is kinetic energy of photoelectron independent of the intensity{{c1::electrons on metal surface can only absorb one photon at a time∴ increasing i…
Published	01/09/2024	{{c1::}}
Published	01/09/2024	stopping potential{{c1::potential difference needed to stop the fastest moving electron travelling with kinetic energy Ek(max)}}
Published	01/09/2024	formula for stopping potential{{c1::\(E_{k(max)} = eV_s\)}}{{c1::wheree = charge on electron i.e. 1.60 × 10-19 (NOTE: charge is taken to be a +ve…
Published	01/09/2024	how does stopping potential stop electron {{c1::photoelectron made to lose energy by doing work against applied potential difference}}
Published	01/09/2024	the work done by p.d. in stopping fastest electron is equal to {{c1::Ek photoelectron}}
Published	01/09/2024	irradiated{{c1::light is being shone onto it}}
Published	01/09/2024	ground state number{{c1::n = 1}}
Published	01/09/2024	how does electron move up between two specific energy shell{{c1::by absorbing photon with energy equal to energy difference between two levels}}
Published	01/09/2024	how to obtain line spectrum{{c1::splitting light with prism or diffraction grating}}
Published	01/09/2024	how does diffraction grating produce line spectrum{{c1::diffracting light of different wavelength at different angles}}
Published	01/09/2024	what is more clearer at creating a line emission spectra, prism or diffraction grating {{c1::diffraction grating}}
Published	01/09/2024	describe line emission spectrum{{c1::series of bright lines against black background}}
Published	01/09/2024	what does each line correspond to in line emission spectrum{{c1::each particular wavelength}}
Published	01/09/2024	what evidence does line emission spectra provide{{c1::electrons in atom exist in discrete energy levels}}
Published	01/09/2024	line absoption spectra of white light{{c1::continuous spectra of colours}}
Published	01/09/2024	line absorption spectra of hot things{{c1::continuous spectrum in visible and infrared}}
Published	01/09/2024	why can hot things emit continuous spectrum of visible/infrared light{{c1::electrons not confined to discrete energy levels}}{{c1::electrons are not b…
Published	01/09/2024	how to get line absorption spectra{{c1::passing light with continuous spectrum of energy(white light) through cool gas}}{{c1::dispersing the light usi…
Published	01/09/2024	explain how is line absorption spectra formed by passing continuous spectrum through cool gas{{c1::at low temp. electrons in gas are at ground state}}…
Published	01/09/2024	conclusion of comparing line absoption spectra and emission spectra{{c1::black lines in absorption spectra match bright lines in emission spectrum}}
Published	01/09/2024	evidence to show light is wave{{c1::diffraction}}
Published	01/09/2024	how does diffraction suggest light is a wave{{c1::if light was particles → just pass through in a straight line, unchanged}}{{c1::or not pass through}…
Published	01/09/2024	evidence to suggest light is a particle{{c1::photoelectric effect}}
Published	01/09/2024	how does photoelectric effect suggest light is a particle{{c1::light is made of photons of discrete bundle of energy → interacts one to one with elect…
Published	01/09/2024	photoelectric effect shows light is particle, diffraction shows light is wave, this is example of phenomenon known as {{c1::wave-particle duality…
Published	01/09/2024	what statement did de Broglie make in his PhD thesis{{c1::if "wave-like" light shows particle properties(photons), then "particles" like electrons sho…
Published	01/09/2024	what does de Broglies equation link{{c1::wave property (wavelength, λ) to moving particles momentum(p = m · v)}}
Published	01/09/2024	de Broglies formula{{c1::\(\lambda = \frac{h}{mv}\)}}{{c1::whereλ = wavelength(m)h = planks constant(6.63×10-34)m = mass(kg)v = velocity(ms-1)}}
Published	01/09/2024	history of de Broglie's wavelength of a particle{{c1::theory not accepted straight away}}{{c1::scientist's evaluated Broglie's theory by peer review}}…
Published	01/09/2024	apparatus used to observe electron diffraction {{c1::electron diffraction tube}}
Published	01/09/2024	explain how does electron diffraction tube produce electron diffraction patterns{{c1::high voltage used to accelerate electrons to high velocities in …
Published	01/09/2024	what theory does electron diffraction tube support{{c1::de Broglies theory that electrons (particle) have wave like properties}}
Published	01/09/2024	how does wave theory apply in electron diffraction{{c1::greater wavelenght results in more spread diffraction pattern::wave theory that applies}}{{c2:…
Published	01/09/2024	why would a neutron, travelling at the same speed as an electron show more tightly-packed diffraction pattern{{c1::neutrons mass in greater → more mom…
Published	01/09/2024	why is smaller wavelengths used in electron microscope{{c1::smaller diffraction effect → less blur}}{{c1::resolve finer details}}
Published	01/09/2024	what effects blur detail on an image{{c1::diffraction}}
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