SAT 2
1eV =
1.60x10^-19J
For two point charges, aim to draw approximately ______ lines from each charge. Oppositely charged: Arrows _______ from _________ to __________ Same charge: _________ in the middle, arrows pointing ________ from charge if __________ or pointing _________ charge if _________
8, connect, positive, negative, asymptote, away, positive, toward, negative
Masses always ______, but ________ can _______ or ________
Attract, charges, attract, repel
Derivation for magnitude of electric field produced by point charge at distance (r) away from it: Use __________, then ________ the formula for ___________ into it and cross out the ____ (___________)
Coulomb's Law, substitute, electric field strength, q+, positive test charge
Length contraction is the:
Decrease in length of an object in motion relative to an observer
Proportionality: 1. Force is _____________ to _____ if _____ and ____ are _________ 2. Force is ____________ to _______ if ___________ 3. Force is ____________ to _____ if _______ and ______ are __________
Directly proportional, q1, q2, r, constant, directly proportional, q1q2, r constant, inversely proportional, r^2, q1, q2, constant
Why can't you travel at the speed of light (mass explanation 2): Because _______, ______ is needed to create _______. It is __________ for an object with ___________ to exist as it would require ____________ and the universe's energy is __________.
E=mc^2, energy, mass, impossible, infinite mass, infinite energy, finite
Lines of force =
Electric field lines
Law of Conservation of Energy:
Energy cannot be created or destroyed, only transferred or transformed
________ is needed/_____ must be done to ________ an object up. Einstein's Theory states that ______ and ________ are _____________ (_______), so a __________ at high speeds is due to a ___________
Energy, work, speed, energy, mass, interchangeable, E=mc^2, gain in energy, change in mass
Electrostatic shielding (___________): a car's ________ metal body protects occupants from ________/__________
Faraday cage, hollow, lightning, electric discharge
It is ___________ for an object to travel ____________ than the __________ because time would _______, space would ___________ and the energy needed would be ___________.
Impossible, at or greater, speed of light, stop, cease to exist, infinite
Relativistic mass is the:
Increase in mass of an object in motion relative to an observer
1 Volt = 1 _____________, so deltaV = ______. Rearrange to give the _________ in moving a charge from point A → B
Joule/coulomb, W/q, work done
Proper length (l(0)): ______________. It is the _________ an observer can measure an object to be
Length of object recorded in rest frame, longest
Rest mass (m(0)): ________________ (it is the _________ mass that can be measured)
Mass of object recorded in rest frame, smallest
Derivation of acceleration: Using _____________, _________ and ________. But as _______, ________. Therefore ____________, where ____ is constant.
Newton's 2nd Law, F=ma, a=F/m, E=F/q, F=qE, a=qE/m, a, constant
Why can't you travel at the speed of light (mass explanation 1): Because of _____________ (______), the _____ needed to ______ an object with ________ would be __________, and an ________ amount of _______ would be needed. This is impossible as the ________ in the universe is ________.
Newton's 2nd Law, F=ma, force, accelerate, infinite mass, infinite, infinite, energy, energy, finite
An inertial reference frame is one in which ________________________________. An inertial reference frame is therefore either ___________ or moving with a ________________.
Newton's Laws of Motion apply, stationary, constant velocity
Work is done ____/____ the ____________, depending on whether charged particles ______ or ______ _________.
On, by, electric field, gain, lose, potential energy
If a charge accelerates in the same direction as the electric field: ______ If a charge accelerates in the opposite direction as the electric field: ______________
Parallel, antiparallel
Motion is only able to measured __________________.
Relative to the observer
Relativity: idea that some things _______ to how they are ___________. Many observed quantities depend on _____________ from which they are ___________.
Relative, observed, reference frame, observed
Coulomb's Law:
The electric force of attraction or repulsion between two charged objects is directly proportional to the product of the two charges and inversely proportional to the square of the distance between their centres. The electric force acts along the line joining the centres of the charges.
Lorentz Factor:
The factor by which measurements made by an observer outside of the rest frame of an object moving at relativistic speeds differs to measurements made by an observer in the rest frame.
Second Postulate of Einstein's Theory of Special Relativity:
The laws of physics are the same in all inertial reference frames, i.e. reference frames with a constant velocity
Time dilation:
The slowing down of clocks that are in motion relative to an observer
First Postulate of Einstein's Theory of Special Relativity:
The speed of light in a vacuum (c) is an absolute constant, i.e. same for all inertial frames of reference
Proper time (t(0)): ___________ between __________ when measured in the _____________ in which the event is ____________ (or its _______________). It is the _________ time that can be measured.
Time interval, 2 events, reference frame, at rest, rest frame, shortest
Newton's 3rd Law is still upheld:
When body A exerts a force on body B, body B exerts an equal and opposite force on body A
Principle of Superposition of Electric Forces:
When more than 2 point charges are present, the force on any one charge is a vector sum of electric forces acting due to other charges present.
We say a charge will ___________ _________ _______/______ to the __________.
accelerate, uniformly, parallel, antiparallel, electric field
The sign for _________ depends on the __________________ and where it's ____________ (_______/______): If it will ______ down, _____. If it will ______ up, _____.
acceleration, sign of the charge, initially headed, attracted, repelled, slow, -a, speed, +a
Charge _________ near _______ points and the _________ is ________ at _________ points. (The component of the electric __________ _______ to the surface of the conductor is bigger for charges ____________, and smaller for charges ___________)
accumulates, sharp, electric field, strongest, sharp, force, parallel, not near points, near points
If a charged particle comes in at an ___________, treat it the same as ______________: _______ and ________ components of ________, __________ velocity is _________, and if coming in _______ to plates, _____________ = _____. Only difference: careful of _____ of a and use _________ instead of g=9.80ms^-2
angle, projectile motion, vertical, horizontal, velocity, horizontal, constant, parallel, initial vertical velocity, 0ms^-1, sign, a=qE/m
In an electric field diagram, the ______ represent the ________ of the _________, the ____________/_______ between the lines represents _________ (___________) of the _____________ at that point (lines ________ __________), arrows always go from ___________ to ___________ and _________________ leave and enter the surface at ______________.
arrows, direction, electric field, concentration, distance, strength, magnitude, electric field, evenly spaced, positive, negative, electric field lines, right angles
The Electric Field Strength:
at a point is the electric force per unit charge experienced by a small positive test charge when placed at that point in the field
Twin Paradox: one twin remains on Earth while other twin travels to distant star and ________ at ______________. The twin on Earth observes travelling twin's clock to run _____, and the travelling twin would have aged _______ than twin on Earth. However, the ____________ also observes the _________ to have aged ______ as Earth is __________ to the ______________. Which of the two twins correct? Twin on Earth is in an ___________, but travelling twin had to _________ and return to Earth, so is not in an ________________. Special Relativity only applies to 2 reference frames in ________________, and does not deal with ____________ reference frames (_________________ shows clocks in ___________ reference frames also __________, so the ___________ is correct.)
back, very high speed, slow, less, travelling twin, twin on Earth, less, moving relative, spacecraft, inertial reference frame, turn around, inertial reference frame, constant relative motion, accelerating, general relativity, accelerating, slows, twin on Earth
Any _________ object in an ____________ experiences an ______________
charged, electric field, electric force
If a __________ particle ________ from one point to another in an __________, its ____________ (____) changes
charges, moves, electric field, potential energy, V
As E is _________, ____ is constant and ____ is constant (as long as ____ and ____ don't change)
constant, F, a, m, q
Reference frame: Set of ____________ used to ________ position. Gives ______________ to observe event from
coordinates, define, set perspective
Shark Shields: a _________ is passed through _______ that produce an ____________ around a diver. Sharks have a ________ in their snout that can sense __________ approximately 1m away. The __________ generated by the shark shield is _____________ than usual prey and makes their receptors ________, which is ________ for the shark. The shark _______ and the diver ________.
current, electrodes, electric field, receptor, electric fields, electric field, much stronger, spasm, uncomfortable, leaves, lives
In a _________, the _________ between the ______ increases the ________ of charged particles. The ____________ allows particles to be _____________ between the gap as deltaV _____. The particles gain ______ as the _____________ does _______ on them (W = ______ = _____ = ______). However, this is in the ______ ________ the Dees only, not in the Dees themselves, as they are _____________ and have ___________ inside the cavity.
cyclotron, electric field, Dees, speed, alternating potential difference, accelerated back and forth, switches, KE, electric field, work, q x deltaV, KE, 1/2mv^2, gap, between, hollow conductors, no electric field
Electric potential difference (______):
deltaV, between two points is the work done per unit charge on a small positive test charge moved between the points, provided all other charges remain undisturbed
The ___________ of the _________ is always ________ for all ____ because v ____ c, so v^2/c^2 < ____ and 1 - v^2/c^2 < _____
denominator, lorentz factor, less than 1, v, <, 1, 1
When an object becomes charged, charges will ___________ over the surface because they are all _______ charges and _____ each other. The ___________ they can get from each other is if they are all _____________.
distribute evenly, like, repel, furthest, evenly spaced
All _____________ produce an __________ (___) around them
electric charges, electric field, E
The ________ between ______________ separated by _________ (___) is: E = ________
electric field, 2 oppositely charged parallel plates, distance, d, deltaV/d
The ____________ between __________ is ________ (same _______ and ______): a ________ in a _______ field will experience the same ______ (both _______ and _________) no matter _____ it's placed
electric field, 2 oppositely charged parallel plates, uniform, length, direction, charge, uniform, force, magnitude, direction, where
When the _________ is _________, the ______ ______ are the same ________ apart (______________) and are all in the same __________: a _________ will experience the ___________ no matter where it is placed between the plates
electric field, uniform, field lines, distance, uniform field strength, direction, test charge, force
Finite parallel charged/conducting plates: The _________ is ___________ in between the plates, and the arrows are always pointing to the ___________ charged plate
electric field, uniform, negatively
Corona dischange: ____________ are __________ near ______ of _______________. These _________ can be __________ enough to __________ the _____/_________ molecules in the _____ near the __________, and the charges can __________ from the conductor.
electric fields, strongest, tips, pointed charged conductors, electric fields, strong, ionise, polar, non-polar, air, sharp points, move away
_________________ objects/particles exert a ______ upon one another: like charges _______, ________ charges attract
electrostatically charged, force, repel, unlike
Work done (W) is similar to _______ (____) (W = ____)
energy, J, Fs
Same _______ may be _______________ in different ________________, i.e. person on boat observes ball falling _________, while person on shore observes ______________.
event, observed differently, reference frames, straight down, parabolic path
Light Clock Thought Experiment: Let _______ be the ______ for ______ to go from bottom -→ top ________. Time taken is ______ (__________). When light clock moves at ______________, l' is the new _______________ travelled by the _____. Forms ______________: l' is _________, ___ is side and ____ (distance travelled by clock in _________) is bottom. Derivation with _____________, and t = ______ = ______, divide everything by _____, and t(0) = _____
event, time, light, mirror, l/c, t(0), constant velocity, diagonal distance, light, right angle triangle, hypotenuse, l, vt, dilated time, Pythagoras' Theorem, s/v, l'/c, c^2, l/c
Muon Decay Experiment: concrete ___________ supporting both ___________ and _____________. Because the muon is travelling at close to the _______________, its _______ to decay when observed by us is ___________: ____________ of the muon ________. Also, length is _________, i.e. the ________ for the muon to travel _____________
experimental evidence, time dilation, length contraction, speed of light, time, dilated, life expectancy, increases, contracted, distance, decreases
v is often expressed as a ____________, i.e. 0.7c, so 1 - v^2/c^2 can be expressed as ____________
fraction of c, 1 - 0.7^2
m = ______
gamma x m(0)
t = ________, where _____ is the ____________
gamma x t(0), gamma, lorentz factor
To a ________________ observer, the __________ (__) for light to pass between mirrors is __________ than the time for ________________ (____) inside the clock
ground-based, time taken, t, greater, stationary observer, t(0)
Relativistic measurements (measured differently depending on __________________) include ___________, _________ and _________
inertial reference frame, time, length, mass
Charged =
ionised
l = _______
l(0)/gamma
Due to the ________________, W = _____ = ______, so _______ = __________.
law of conservation of energy, KE, 1/2mv^2, q x deltaV, 1/2mv^2
Lightning Rod: During _____________, the _________ in the Earth are _______ deeper in the ground, so the Earth surface becomes _________ charged. The lightning rod therefore becomes ___________ charged, and charges ________ around _________ to form ___________. _________ occurs and a stream of ___________ are _______ back towards clouds, _________ some of the _______ charge to help _______ a _____________. OR If there is too much ________ charge in the clouds, it eventually ______ over a distance to the __________ charged rod, resulting in a big ______ (i.e. __________). The rod is __________ and the _______ flow down the ________ rod into the Earth.
lightning storms, electrons, repelled, positively, positively, accumulate, sharp points, strong electric fields, corona discharge, positive air molecules, repelled, neutralising, negative, prevent, lightning storm, negative, jumps, positively, spark, lightning, Earthed, electrons, insulated
Relativistic momentum: Since the ______ of an object ______ at high speeds, and p = ______, p = _________ as m = ________
mass, changes, mv, gamma x m(0) x v, gamma x m(0)
There is ____________ inside a ____________ because if you were to do a ___________ of all ____________ at points anywhere ________ the cavity of sphere, they ________. Therefore, the _______ on a __________ inside is also _______.
no electric field, hollow conductor, vector sum, electric fields, inside, cancel, force, positive charge, zero
Photocopier: the _________________ is ________ charged (i.e. have a ________ layer), a _________ is produced on the drum in the form of _________ (_____ is reflected, and the drum __________). ________ charged _______ is then applied on the drum as it as attracted to the _______ parts of the drum, and the ______ is transferred to the ________ because the _______ has a greater _________ of ______ charge (______________). The _______ is fixed on the paper and the ________________ ready for the next copy with a _______________ (_______ charge, and _________ is scraped off)
photoconductive drum, positively, selenium, latent image, charges, light, conducts charge, toner, positive, negatively, toner, paper, paper, concentration, positive, positive transfer corona, image, drum is cleared, negative separation corona, neutralises, excess toner
Direction of electric field: direction a _____________ would move
positive test charge
When a ____________ is moved _______ to the positive charge producing an electric field, it ________ _______________ (work must be done _____/____ the field)
positive test charge, closer, gains, electrical potential energy, against, on
If q is ________, the electric field is _______________ from q If q is _______, the electric field is _______________ q
positive, radially away, negative, radially toward
There is a _____________ (____) between 2 points in an ______________ for a __________.
potential difference, deltaV, electric field, given charge
The __________ a charged particle will _________ is __________ on _________ it is situated in the ___________ (_________/______ from + or -)
potential energy, store, dependent, where, electric field, closer, further
W =
q x deltaV
The electric field diagram for a hollow charged conductor, there are lines leaving/entering at _______ to the sphere, there are _______/_______ ______ on the outside of the sphere and there are _____ __________ inside the sphere
right angles, positive, negative, charges, no electric field lines
Length contraction is in the ________________ as the object's __________
same direction, motion
The ____________ of two points or the ________ of an object travelling at very high speed appears ________ or __________ in _________ reference frames
separation, length, shorter, contracts, moving
If the ______ of a charge changes, _________ switches from __________ <-→ __________
sign, force, attractive, repulsive
Two events that are _________ in one ______________ are ______________ in another if one reference frame is moving at ________________
simultaneous, reference frame, not simultaneous, constant velocity
Simultaneity: two events may appear to happen _____________ in one ________________ (i.e. ___________ between events is _______). In another _____________, the same two events might be observed to _____________ at the same _________________ (i.e. ____________ between events ___________)
simultaneously, reference frame, time interval, zero, reference frame, not occur, instant in time, time interval, not zero
When a ____________ is _____/_____ from one plate to another, ________ must be done on the charge (W = ____, except ___ is now the _______ (___) between the 2 charged plates)
small positive test charge, moved, forced, work, Fs, s, distance, d
If v is ______, we ________, as the ________ is pretty much ____
small, barely notice, lorentz factor, 1
Relative velocity: Car A 50km/h, Car B 60km/h Car A: self ___________, B moving ____________________ Car B: self ___________, A moving ___________________
stationary, forward away at 10km/h, stationary, backward away at 10km/h
Electric Fields ________ _________________.
store, electrical potential energy
The ______ taken for an event is always _________ when measured from a _____________ reference frame, i.e. ____ is always ________ than _____
time, greater, moving, t, greater, t(0)
Test charge: _____ charge with a ______ (____________) ___________, i.e. ______ enough not to _________ with existing ___________, but _____ enough to still be __________ and experience an _________
tiny, weak, negligible, electric field, small, interfere, electric fields, big, charged, electric force
Time/length/mass at the speed of light: _________ = __________ = ____, so the ____________ of the ________ equals _____ and gamma approaches ____. Time approaches _____, length approaches ____ and mass approaches ________.
v^2/c^2, c^2/c^2, 1, denominator, lorentz factor, 0, infinity, infinity, 0, infinity
Force is a _______ quantity: must state if it is ______ or _________ or use __________, and if more than ____ particles are involved, __________ must be used.
vector, attraction, repulsion, arrows, 2, trigonometry
Einstein's Theory of Special Relativity predicts significantly different results to classical velocities for _________________
velocities approaching the speed of light (c)
1 electron volt is the ________ when an ________ moves through a ______________ of ______.
work done, electron, potential difference, 1 volt