knowledge Flashcards
pressure law
p/T constant at V constant
Charle’s law
v/T constant at p constant
Boyle’s law
pV constant at T constant
real gas approximates to ideal gas at
low pressure and high temperature (also low density)
ideal gas assumptions
no intermolecular forces, elastic collisions between the molecules, molecules are treaded as points, there is no time spent in the collisions, molecules are monoatomic
electromagnetic spectrum from lowest frequency to the highest
radio waves, microwaves, infra-red waves, visible light, UV, X-rays, gamma rays
wavelengths of visible light
400- 750 nm
frequencies of visible light
400-800* 10^12 Hz
total internal reflection
there is no refraction, only reflection
standing waves
interference of two waves traveling in the opposite directions with the same amplitudes and same frequencies,
intensity of standing wave
maximum-antinode, minimum-node
potential divider
used to produce variable power supply
sensors
more light/temperature- lower potential difference across the sensors
primary cell
non-rechargeable (alkaline batteries)
secondary cell
rechargeable (lid-acid car battery)
alpha radiation
low penetrability, paper to absorb it
beta radiation
medium penetrability, a few mm of aluminum to absorb it
gamma radiation
high penetrability, 10 cm of lead to absorb it
Rutherford scattering
evidence of existence of a nucleus
emission and absorption spectra
evidence of electron energy levels
structure of matter
hadrons, leptons, exchange particles
hadrons
baryons- 3 quarks, mesons- 1 quark and 1 antiquark
quark confinement
isolated quarks and gluons cannot exist
function of moderator
slows down neutrons to increase the probability of them interacting in further reactions
function of control rods
control the chain reaction by absorbing neutrons
function of heat exchanger
allows nuclear reaction to be sealed off from the rest of the environment
thermal energy transfers
conduction, convection, radiation, (evaporation)
Wien’s law
The higher the temperature of the body, the lower the maximum wavelength and higher the intensity of emitted light.
greenhouse gases
methane, water vapour, carbon dioxide, nitrous oxide
SHM spring assumptions
friction is negligible, mass of the spring is negligible compared to mass of the load, g is constant
SHM pendulum assumptions
air fricition is negligible, mass of the string is negligible compared to mass of the load, maximum angle of swing is smaller than 5 degrees
adding more slits to multiple slit diffraction causes
more intense primary maxima, narrower primary maxima, secondary maxima less significant
thin-film interference
v1>v2- reflection out of phase (+π), transmitted in phase
red shift
source moving away from the observer, decreased frequency
blue shift
source moving towards the observer, increased frequency
charge on a hollow conducting sphere
charge uniformly distributed on the outside of the sphere, no charge on the inside of the sphere, hence zero electric field inside, and constant electric potential
gravitational field inside the hollow object
zero, as per Newton’s shell theorem, constant gravitational potential
step-up transformer
increases voltage and decreases current, good for transmission of electric power to avoid large losses of power
step-down transformer
decreases voltage and increases current, protection of end-users, high voltage is dangerous
losses in the transformer
resistance of the winding (heat), eddy currents in the core, flux losses (flux not going through the secondary coil)
increasing efficiency of a transformer
core with high permeability, laminating core
rectification of AC to DC
single diode- half rectification
diode bridge- full-wave rectification
smoothened rectification
capacitor (current still fluctuates but less-output ripple, time constant of the capacitor must be large enough)
influence of light over photoelectric effect
number of electrons emitted depends on the intensity of light (number of photons), energy of electrons depends on the frequency of the light
Davisson and Geimer experiment
electron diffraction, evidence of their wave-like properties
hydrogen emission spectrum
Lyman series (n=1)- UV Balmer series (n=2)- visible light Paschen series (n=3)- IR
Bohr atom model assumptions
quantised angular momentum, quantised energy
Schrodinger model of atom
describes positions of electrons by probability density functions
estimates from Heisenberg uncertainty principle
energy of electron in an atom, impossibility of electron to exist within a nucleus of atom, lifetime of an electron in an excited state
white light incident on diffraction grating
white center of diffraction pattern, closeness of colours to centre by decreasing vawelength (lowest wavelength is closest), greater the order the wider the pattern, gaps between first-order and second-order spectra
gravitational potential due to multiple objects
sum of potentials due to each obejct
pair production condition
photon with large enough energy must interact with nucleus (nucleus conserves momentum)
electron’s path in a non-parallel electric field
parabolic path
total energy of orbiting satellite
negative
reasons for establishment of the standard model
incorporates strong and weak nuclear forces between nucleons, explains decay of neutron to proton, incorporates conservation rules
measuring half-life
Geiger counter
