Physics Mock Exam 2021 Flashcards
Circuit set up needed to investigate how the ______ of a wire affects its resistance.
Circuit needs a battery, switch, ammeter (connected in _______) , voltmeter (connected in ________), ________ clips and a ______ ruler with the _____ wire.
Use CGP too see circuit diagram
length
series, parallel, crocodile clips, metre ruler, test wire
Ammeter measures the _______ (in units called _______) flowing through a component/circuit - it can be put ________ in the ____ circuit, but must be placed in ______ with the _________ (eg ____ wire) - NEVER in ________.
current, ampere/amps, anywhere, main, series, component, test wire, parallel
Voltmeter measures the _______ _______ across the component (e.g. ____ ____) - it must be placed in ________ with the ________ (in this case the test wire) - NOT any other bit of the circuit e.g. the _______
potential difference, test wire, parallel, component, battery/power source
Experiment investigating ______ of wire and _______.
1) Place a ________ clip to the wire level with __ cm on the _____
2) Attach the second _______ clip to the wire some ________ away from the first _____ (e.g. 10cm away)
3) Close the ______, then record the _______ through the _____ and the _____ across it
4) Open the _______, and move the second _______ clip some distance _______ away. Close the _______ again and record the new ______, ______ and ____.
5) ______ this for a number of different ______ of wire between the _____.
length, resistance
crocodile, 0, ruler
crocodile clip, distance, clip
switch, current, wire, p.d.
switch, crocodile clip, further, switch, length, current and p.d.
repeat, lengths, clips
Important equation needed to calculate and use during this experiment
V = _ _ where V = \_\_\_\_\_\_\_ _ = Current _ = \_\_\_\_\_\_\_\_\_
You can _______ this equation to find current and ________ if you have all the measurements needed e.g. R = V/I
V = IR V= Potential Difference (measured in volts V)
I = Current (measured in amps A)
R = Resistance (measured in ohms Ω)
6) Use measurements of ______ and ___ to calculate the _________ for each length of wire - This can be found using R = / (from V = __)
7) Plot a graph of _______ and _____ of wire (Y axis = _______, X axis = _______)
8) You should find that the longer the wire, the _______ the ________.
9) Graph should be a _______ line that goes through the ______ - so resistance is ________ _________ to length
current, p.d., resistance, R=V/I, from V=IR
current, p.d., resistance, R=V/I, from V=IR
resistance, length of wire, Y axis = Resistance X axis = Length of wire
Longer the wire, greater the resistance
Straight line through origin - resistance and length are directly proportional
If the graph doesn’t go through the origin, it could be because the ______ clip wasn’t attached exactly at __ cm at the _____, so all the length readings are slightly ________ - This is a _________ error
You can find the ________ off the graph to ________ resistance for other lengths.
first, 0cm, start, inaccurate, systematic error
gradient, estimate
A series circuit consists of electrical ________ connected one after another in a single ____.
components, loop
In parallel circuits, electrical _______ are connected ________ one another in multiple _____.
component, alongside, loops
Circuit rules for Series circuit
An ______ will pass through every ________ on its way round the circuit. If one of the bulbs/component is broken , then the _______ will not be able to ____ round the circuit. if one bulb goes out, they ____ go out.
electron, component, current, flow, all
Current in series
Current is the ______ anywhere in the circuit as each _____ has to flow through all ________.
I₁ = __ = __
same, charge, components
I₁ = I₂ = I₃
if the resistance of any ________ in a series circuit changes, this will change the value of the _______ in the circuit.
component, current
P.D. in series
P.D. is ______ as ____ done by battery is equal to _____ _____ done on all ________.
Vt = ___ + ___
shared, work, total work, components
Vt = V₁ + V₂
(P.D. across all components = Total/Power supply P.D.)
If the resistance of any ________ in a series circuit changes, this will change the ____ across ___ of the ________.
component, P,D, all, components
Resistance in series
Net (_____) Resistance = The ______ of all resistors _____ together
Adding resistors in series ______ the resistance as ______ only has one ____ to follow, so it must deal with all the _________.
Total, resistance, added
increases, current, path/loop/branch, resistance
Parallel circuit rules
An electron will ____ pass through every ______ on its way round the circuit (due to the _______ branches).
If one of the bulbs/component is broken, then _______ will still ____ round the circuit through the other ____. if one bulb goes out, the other ____ on other _____ will remain ___.
not, component, multiple, current, flow, loop, bulbs, loops, on
Current in parallel
Current is ______ between the multiple ______.
The sum of all the current in all branches is equal to the ______ ______.
If one loop has less resistance than other, it’ll have ____ _______ flowing through it.
It = __ + __
shared, loops/branches
total current
more current
It = I₁ + I₂
If the resistance of any ________ changed in a parallel circuit changes, the value of the _______ in that _____ and the _____ _______ supplied by the battery will _____.
It does not affect the _____ in other _____.
component, current, loop, total current, change
current, loops
P.D. in parallel
The full, total power supply ____ is delivered to each _______.
V1 = ___ = ____ = ____
P,D, branch/loop
V₁ = V₂ = V₃ = Vt
If the resistance of any _______ in a parallel changes, this will have ___ ______ on the ____ across any of the ________.
component, no effect, p,d,, components
Resistors in parallel
The ___ resistance _______ as more components are added, because there are ____ ______ for the ________ to flow through.
1/Rt = ___ + ___
net, decreases, more paths, current
1/R = 1/R₁ + 1/R₂
Check the brightness of bulbs experiment.
Oke
A power supply does ____ on a charge, and so transfers _____ to it.
Charges transfer ______ to a component as they ____ through it, by doing w___ against the ______ of the component.
work, energy
energy, pass, work, against resistance
Work done is simply better known as _____ _______.
energy transferred
The equation to find the work done is as follows.
J=\_\_ \_\_\_\_ done (\_\_\_\_) = \_\_\_\_ (V) + \_\_\_\_\_\_ (C)
J=VQ
Energy transferred (work done) [Joules, J] = P.D. (Volts, V) x Charge (Coulombs, C)
J=VQ can be rearranged to
V=__/__
C=__/__
V=J/Q
C=J/C
Formula triangle for J=VQ
J
V Q
Learn this
A loudspeaker contains a coil of ___ (______) which surrounds one ____ of a permanent _______. The other pole surrounds the ____.
coil of wire (solenoid), pole, magnet, coil
check cgp image
An _______ current flows through the ___ of wire, which is wrapped around the ____ of a c___.
alternating current, coil of wire, base of a cone
The interaction between the ______ fields of the permanent _____ and the _____ forces the coil to move in one _______.
As it’s an _______ current, the current changes ______, forcing the coil back in the other ______.
magnetic fields, magnet, direction
alternating, direction, direction
Electromagnetic induction is the induction of a ___ (and current if there’s a complete _____) across a ______ which is experiencing a change in _______ ______.
P.D, complete circuit, across a conductor, change in magnetic fields
You can think of a p.d. is being induced whenever a _______ ____ line is ____ or crossed by the _________.
If the ____ is part of a complete circuit, it also induces a _______.
magnetic field line, cut or crossed, conductor
coil, current
Two different situations of EM induction
- If the _______ field through an electrical conductor changes (changes ____ or ________).
- If an _______ conductor and a ______ field ____ relative to each other. E.g. moving a ______ in a conductor or moving a ________ in a magnetic field.
magnetic field, shape, reverses
electrical conductor, magnetic field, move, magnet, conductor
- If you move a m____ into a c___, it induces a ___ across the ____ of the ____.
magnet, coil, p.d. ends of the coil
- If you move the m_____ (or c___) in the opposite direction, then the P,D./______ will be ______, Likewise, if you flip the magnet so the other ____ enters the coil, the ____/current will be _______ too.
magnet, coil, current, reversed
pole, P,D, reversed
- If you keep the magnet (or the ___) moving ______ and ______, you produce a p.d. that keeps swapping _______.
coil, backwards and forwards, directions
You can also induct a p.d. by turning a magnet ___ to ___ in a ___ (or turning a coil inside a ______ ____).
end to end, coil, magnetic field
- When you’ve turned the magnet through a half a turn, the direction of the magnetic field ______.
When this happens, the p,d, _____, so the current flows in the _______ direction around the ___ of wire,
reverses
reverses, opposite, coil
- As you turn the magnet, the ______ field through the coil ______. This change in ______ field induces a ___, which can make a ______ flow in the wire.
magnetic, changes, magnetic field, p,d, current
- If you keep turning the magnet in the same direction (e.g. always clockwise), then the p.d will keep on re____ every ____ turn and you’ll get an _______ current.
reversing, half turn, alternating current
Increase p.d. induced by increasing the _____ of the movement, increasing the ______ of the ______ field or having more ____ per ____ length of ___ of wire,
+speed of the movement, +strength of the magnetic field
+more turns per unit length of coil of wire
Current is the flow of electrical _____ around a circuit
It is measured by an _______ and its units is _____ __
charge
Charge - Electrons are _______ charged particles and they transfer ______ _____ from a cell to _______.
components
P.D. Is the _______ force which gives the current the _____ to _____ round the circuit.
driving force, energy, flow
Charge can be found using current and time
Q = __
Charge (______, __) = C_____ (____ __) + T____ (______ __)
Q
I T
Q=IT
Charge (Coulombs C) = Current (Amps A) x Time (seconds, s)
Current (A) from charge (C) and time (__)
I = ___
Time (__) from Current and charge
T = ____
s
I=Q/T
T=Q/I
practice the use of this equation
One ampere is the current that flows when one ______ of _____ passes a point in a circuit per ______
coulomb, charge, second
Electrons in an atom sit on different ______ _____ or shells. Each shell is a different distance from the ______.
energy levels, nucleus
An electron can move __ one or more energy levels if it absorbs ___ radiation with the right amount of ______.
When it does move up, it moves to a _______ filled or empty ____ and is said to be e____.
up, EM radiation, amount of energy
partially, shell, excited
The electron will then fall back to its _______ energy level, and in doing so will ____ the same amount of ______ it absorbed. The energy is carried away by ___ _______.
original energy level, lose, energy, EM radiation
Visible light, ____ and X-rays are all created when atoms lose ______ by an ______ dropping down ______ levels and emitting energy in the form of ___ ________ (e.g. UV radiation).
This is how UV is made!
UV, lose energy, electron , dropping down energy levels, EM radiation
Uses of UV
UV radiation can kill _______ that are present in _____ - this sterilises the _____ and makes it safe to _____.
Good for the skin as it’s responsible for ______ __ production.
kill bacteria in water, sterilises water, safe to drink
good for skin, vitamin D production
More uses of UV
- Oxygen in the _____ atmosphere ______ UV and is converted into ______ gas
- Ozone gas ______ large amounts of ___ radiation, which protects all _____ organisms from it’s _______ effects
upper atmosphere, absorbs UV, ozone gas
absorbs, large amounts of UV, living organisms, harmful effects
High energy ___, __-rays and ______ rays is a type of i_______ radiation. The absorption of _______ radiation can knock _______ off shells due to their high ______, turning the atoms into ____.
This can lead to _______ in cells, which can lead to _____.
UV, X-rays, gamma rays, ionising radiation, ionising radiation, knock electrons off shells, high energy, into ions
mutations in cells –> cancer
UV is absorbed by the skin, where it can cause damage to ____, can lead to skin ______.
Can also ______ your eyes and cause
_______
Can cause skin to ___ prematurely.
damage to cells, skin cancer
damage eyes, blindness
skin to age prematurely
Radio waves and all EM waves are just _______ _______ and _______ fields.
oscillating electric and magnetic fields = Radio waves and EM waves
_______ currents (A.C.) in electrical circuits causes charges to ________. - This creates an oscillating _______ and _______ field - an EM wave (e.g. radio waves)
This EM wave will have the same _______ as the current that created it. So a current with a _______ corresponding to the radio wave part of the spectrum is used so that _____ waves are produced.
Alternating current, charges to oscillate, oscillating electric and magnetic field - so an EM wave
EM wave same frequency, frequency, radio waves are produced
EM waves also cause _____ particles in a co_____ to _______. If the charged particles are part of a ______, this induces an a.c. of the same _______ as the EM wave that induced it.
charged particles, conductor, oscillate
circuit, frequency
So if you’ve got a _______ and a receiver, you can encode ________ (e.g. a TV show) in an a.c. and then transmit it as a _____ wave.
The wave induces an ____ in the receiver (e.g. the aerial) and that’s how you get information.
transmitter, encode information, radio wave
a.c.,
if that was hard to understand ignore that and learn the following few cards
Oke
Radio waves can be produced by, or can themselves induce _______ in electrical circuits. When radio waves are absorbed by a conductor, they create an _____. This electrical current has the same _______ as the radio waves. The conductor could be, for example, an ____ on a radio.
oscillations, a.c. (alternating current), same frequency, aerial
Information is ____ into the wave before _______, which can then be decoded when the wave is ______. _______ and radio systems use this principle to broadcast information.
coded, before transmission, received, television
A wave is a regular ________ that transfers energy through a ______ or vacuum.
regular disturbance, transfers energy
Amplitude - _______ from the ____ _______ to a crest or ______.
Amplitude - Maximum displacement from the rest position to a crest or trough
Wavelength - Distance between two ______ ______ on two ______ ______ of a wave
identical points, adjacent cycles
Crest - _______ point of a wave
Highest - Crest
_______ - Lowest point of a wave
Trough - Lowest
Frequency of waves - The number of _______ ______ passing a certain point ___ ________.
It is measured in _____ (__). 1___ is 1 wave per second
Frequency - Complete waves per second
Hertz (Hz) 1Hz = 1 wave per second
Period of waves - The amount of ____ it takes for ___ ______ of a wave to ____ a certain point.
Period = __/________
Period - Time taken for one cycle to pass a certain point
Period = 1/Frequency
Waves through a medium
The particles of the medium ______ and transfer _____ between each other. BUT overall, the particles stay in the same ______ - only _____ is transferred
particles of medium vibrate - transfer energy
particles stay in the same place - only energy is transferred
Water waves are _______ _____.
Transverse waves
Transverse waves - The oscillations are ________ to the direction of ______ ______ (which _______ the wave travels)
Transverse waves - Oscillations perpendicular to direction of energy transfer and wave travels
Wave speed equation - can be used for all types of waves
wave speed (___) = f________ (__) x _________ (__)
wave speed (m/s) = frequency (Hz) x wavelength (m)
Important unit conversions
1kHz = ______ Hz 1MHz = __________ Hz
1kHz = 1000 Hz 1MHz = 1,000,000 Hz
Find frequency from wave speed equation
Frequency (Hz) = ________ (__) / _________ (__)
Frequency (Hz) = Wave speed (m/s) / Wavelength (m)
Find wavelength from wave speed equation
Wavelength (__) = _________ (__) / _________ (__)
Wavelength (m) = Wave speed (m/s) / Frequency (Hz)
Ripple tank
You can generate waves in a _____ tank using a ______ ______ supply attached to a _____.
The dipper moves __ and ____ to create water ____ at a fixed ________.
Ripple tank - Use variable power supply attached to dipper
Dipper moves up and down - Water waves at a fixed frequency
Ripple tank
An alternative method is using a _____ _______ which generates ____ with a _____ ____ frequency.
Signal generator - waves with a known fixed frequency
Measure frequency in ripple tank
To measure the frequency, you’ll need a ____ and a _________.
Cork and a stopwatch
Measure frequency in ripple tank
1) Float the ___ in the ripple tank. It should bob __ and ____ as the waves ____ it
2) Start the stopwatch when the ____ is at the top of a ___. Time how ___ it takes the ____ to complete ___ bobs
Float cork on tank. Bob up and down as waves pass it
Cork on top of bob - START STOPWATCH
Time cork completing 10 bobs
Measure frequency in ripple tank CALCULATIONS
3) Divide this time by ___ to get the time for ___ bob - i.e. the ______.
4) Calculate the frequency using for the formula
frequency = __/_______
Divide time by 10 - time for 1 bob - The period of a wave
Frequency = 1/Period
Find frequency from period
Frequency = __/________
Frequency = 1/Period
Measure wavelength in ripple tank - use a _____ light]
1) Place a card covered with _______-_____ paper _____ the ripple tank
2) Turn on the _____ light and adjust its ________ unit the waves appear to ______
3) Using the squared paper, measure the ______ that e.g. 5 waves cover. Divide this distance by the _______ of ___ to get an _______ _______.
Wavelength in ripple tank - use a strobe light
1)Card with cm2 paper behind tank
2) Turn on strobe light, adjust frequency till waves ‘freeze’
3) Measure the distance of the waves. Divide distance by the number of waves - average wavelength
Measure wave speed using a _____ and _______ in ripple tank.
1) Place a large piece of _____ n___ to the tank
2) As the waves ____ across the tank, one person should track the ___ of one of the ____ on the paper using a _______.
Using a ruler will help make sure your line is ______ to the direction the wave travels.
Pencil and stopwatch
1) Large piece of paper next to tank
2) Waves move - one guy track the path of one of the crests on paper using pencil
Use ruler to make line parallel to direction the wave travels
Measure wave speed in ripple tank
3) Other person should ___ how long it takes the first to draw a line of a certain ______ (e.g. 20cm).
4) Calculate wave speed by plugging in the ______ of the line (the d______) and the _____ taken to draw it into the formula ______= _________/_______
3) Other person time how long it takes to draw a line of a certain length
4) Wavespeed - length of line is distance - time taken is time
USE SPEED = DISTANCE/TIME
Calculate Speed from distance and time
Speed = ________/_______
Speed = Distance/Time
Calculate distance from speed and time
Distance = ____________
Distance = Speed x Time
Calculate time from speed and distance
Time = ______/________
Time = Distance/Speed
Ripple tank experiment
- Make sure you ______ the experiment _____ times and take an _______.
- Make sure its a ___ test by keeping the equipment the _____ and the ______ you aren’t testing the ____ every time (e.g. _____ of the dipper, the ______ of the power supply, the ____ of the water etc).
Repeat experiment many times - take an average
Fair test - Same equipment, variables not tested also the same - position of dipper, voltage of power supply, depth of water
When a wave meets a ______ between two materials, 3 things can happen
- A______
- ________
- ________
Absorption
Transmission
Reflection
Wave meets a boundary between two materials
The wave is ABSORBED by the ______ material - its energy is _______ to the material, often causing _______.
Wave ABSORBED by second material - energy transferred to material - causes heating
Wave meets a boundary between two materials
The wave is TRANSMITTED through the _______ material - the wave carries on _______ through the new ______. This often leads to _______ (see later).
Wave TRANSMITTED through second material - wave carries on travelling through material - leads to refraction
Wave meets a boundary between two materials
The wave is REFLECTED - this is where the incoming ray is neither ______ nor _______, but instead is ____ ____ away from the second material.
Wave REFLECTED - incoming ray not absorbed or transmitted - instead sent back away from second material
Wave meets a boundary between two materials
What actually happens depends on the _______ of the wave and the _______ of the materials involved.
Absorption, transmission and reflection is true for all ___ of waves.
What happens - depends on wavelength of wave - and properties of the materials involved
True for all types of waves
Refraction - Waves changing ______ at a boundary.
Waves travel at different _____ in different materials. So, when a wave crosses a ______ between materials, it changes ______.
Refraction - Waves changing DIRECTION at a boundary
Waves - different speeds in different materials
If wave crosses a boundary between materials, speed of wave changes
Refraction
The frequency of the wave stays the ____ (it can’t _____) as it crosses a _______ from one medium to another.
As Wavespeed = _______x________, this means that if speed changes, the ________ must also _____.
The wavelength decreases if the wave ____ ____, and increases if the wave ____ ____.
Frequency of wave stays same as it crosses boundaries
Wavespeed = Frequency x Wavelength - so if speed changes, wavelength must also chabge
Wavelength decrease if speed slows down, increase if speed speeds up
Refraction
If the wave hits the boundary at an ____ to the ______, this change of _____ causes a change in _______ - this is called _______.
If the wave is travelling along the normal, it will change _____ but it’s not _______.
Wave hits boundary at angle to normal - change of speed causes change in direction - REFRACTION
Along normal - change speed but not refracted
________ diagrams show a wave slowing down as it crosses a ______.
A wavefront us a line used to represent a _____ (or ______) of a wave.
Wavefront diagrams - Show waves slowing down as it crosses boundaries
Wavefront - lines used to represent a crest or trough of a wave
Wavefront diagrams
Wavefronts closer together than before - shows a ______ in _______ (and so ______ in ______ as well)
Wavefronts closer - Shows wavelength decrease - also decrease in speed
Wavefront diagrams
Wavefronts further apart than before - shows a ______ in _______ (and so ______ in ______ as well)
Wavefronts further apart - Wavelength increase - also increase in speed
Wavefront diagrams
Check CGP for more info
k
Refraction
The greater the change in speed, the more a wave ____ (changes _______)
Bigger change in speed - More a wave bends/refracts/changes direction
Refraction
Bends towards normal if wave ____ ____, and away from normal if it ____ ____
Slows down - towards normal
Speeds up - away from normal
Water waves also show some of the behaviours of ____ and ____ waves - with water the benefit is you can actually see the ________.
A _____ tank can be used to demonstrate _______ and ________.
Water also shows behaviour of light and sound waves - benefit with water is waterfronts can actually be seen
Ripple tank can show reflection and refraction
Reflection on ripple tank.
When water waves hit an object, they are ______ by it.
Angle of ______ and angle of ________ that meet the _______ lines are always ______.
Reflection on ripple tank
Water waves hit an object - reflected by it
Angle of incidence = Angle of reflection
Angles that meet the normal line
Refraction on ripple tank
When water waves pass into ______ water, they slow down.
If they’re at an _____ to the normal, they will ______.
Into shallower water - waves slow down
Angle to normal - waves will refract
