All of Higher Physics

sketch the velocity-time graph for a ball thrown vertically upwards that falls back down to earth (neglecting air resistance) look like?

how do you calculate the magnitude of the force of friction acting on an object moving down a slope?

f=(mgsinθ) - friction

what is the area underneath a force-time graph equal to

impulse / change in momentum

initial vertical component (u) of a velocity v at angle theta

u = vsinθ

initial horizontal component (u) of a velocity v at angle theta

u = vcosθ

law of the conservation of momentum

total momentum before a collision is equal to total momentum after a collision in the absence of external forces

how do you show that a collision is elastic

kinetic energy before equals kinetic energy afterwards

how do you show that a collision is inelastic

kinetic energy before does not equal kinetic energy afterwards

direct current

a flow of electrons in one direction from negative to positive terminals of a power supply

alternating current

an electric current that constantly reverses its direction and instantaneous value over time

what is an oscilloscope used to display

voltage wave forms

what does the y-axis on an oscilloscope show

voltage across a component

how do you get the period of a wave from an oscilloscope

wavelength in boxes x timebase

how do you get the frequency from an oscilloscope

1/period

how do you get the peak voltage from an oscilloscope

amplitude x Y-gain

current in a series circuit is...

the same at all points

when resistors are connected in series, how do you calculate the total resistance?

Rt = R1 + R2 +....

in a parallel circuit the supply current is equal to...

the sum of the currents through each branch

if components are in parallel what is the same across all of the branches

potential difference

in a potential divider, the ratio of the resistor values is equal to...

the ratio of the potential differences

what is the gradient of a "Vtpd" versus "current from a cell" graph equal to?

negative internal resistance

emf

the electrical energy supplied to each coulomb of charge which passes through the source

short circuited cell

a cell that has two terminals connected together with just a wire which has (almost) zero resistance

what is the y-intercept of a "Vtpd" versus "current from a cell" graph equal to?

the emf

what is a scalar quantity

a quantity that has only magnitude

what is a vector quantity

a quantity that has both magnitude and direction

for displacement what must always be stated

distance and a direction (most likely a bearing)

how would you work out a resultant vector

add the vectors tip-to-tail and the use pythagoras to calculate the length. SOHCAHTOA to find angle.

the meaning of the individual letters of SUVAT

displacement, initial velocity, final velocity, acceleration, time

what is the gradient of a displacement-time graph equal to

velocity

what is the area under a speed-time graph equal to

total distance traveled

what is the area under a velocity-time graph equal to

displacement

what does the velocity-time graph for a bouncing ball look like

acceleration for a freefalling object on Earth

-9.8 m s⁻²

vertical acceleration of a projectile

-9.8 m s⁻².

newtons first law

if an object is at rest or moving at a constant velocity in a straight line then the forces acting on the object are balanced

newtons second law

the acceleration of an object is directly proportional to the unbalanced force acting on it and inversely proportional to its mass (f=ma)

newtons third law

every action has an equal but opposite reaction

what happens to your apparent weight when accelerating upwards

apparent weight is greater

if a lift is moving down at constant speed what will your apparent weight be

apparent weight is the same

what happens to your apparent weight when accelerating downwards

apparent weight is greater

impulse

the change in momentum during a collision or explosion

newton's universal law of gravitation

each body with a mass will exert a force on each other body with mass

two postulates for special relativity

the laws of physics are the same in all frames of reference / the speed of light in vacuum has the same value c in all frames of reference

what is a light year

the distance light can travel in a year

what is length contraction

the observed decrease in length of an object moving relative to an observer compared to that when they are in a stationary frame of reference

what is time dilation

the observed increase in time interval of an object moving relative to an observer compared to that when they are in a stationary frame of reference

what is the doppler effect

the change in frequency observed when a source of sound waves is moving relative to an observer

what happens to the frequency of a wave as a source moves towards an observer

the frequency increases

what happens to the frequency of a wave as a source moves away from an observer

the frequency decreases

what is the relationship between speed of the galaxy (v) and distance form an observer (d)?

v is directly proportional to d. / v = H₀d

what evidence is there for the expansion of the universe

galaxies farther away from us are moving faster

what is the dark matter

the matter in the universe that is not visible

what is dark energy

something that is overcoming the force of gravity to cause the universe to expand at an ever greater rate.

what evidence is there for the big bang

the relatively uniform cosmic microwave background radiation is the remains of energy created just after the Big Bang. the universe is expanding, the other galaxies are moving away from us

milli

x10⁻³

micro

x10⁻⁶

nano

x10⁻⁹

equation for the energy gained by an electron when passing through a potential difference of V

W=QV

how much energy is stored in a capacitor of capacitance C with a potential difference of V applied across it

E=½ CV²

which energy band is full of electrons in an intrinsic semiconductor

valence band

charge on an n-type semiconductor

neutral (no charge)

random uncertainty

(max - min) divided by number of readings

reading uncertainty of digital scale

one in the least significant digit of the display

reading uncertainty of analogue scale

half the smallest division

overall uncertainty (single quantity)

the largest out of the reading, random and calibration uncertainties

overall uncertainty (calculated quantity)

the largest percentage uncertainty in the data being calculated

percentage uncertainty

(Absolute uncertainty / measurement) x 100

systematic uncertainty

a problem with the apparatus or method which causes an error in every single reading

intrinsic semiconductor

undoped group 4 semiconductor eg silicon

extrinsic semiconductor

semiconducting group 4 material with impurities of group 3 or group 5 material

doping

when very small amounts of impurities are added to the intrinsic semiconductor, this changes the properties of the material

diode

a component made of n-type and p-type material grown together. It is a device that allows current in one direction only

p-n junction

where the n-type and p-type materials are joined, this allows electrons and holes to diffuse across the gap

conductor

solid material that has electrons in the conduction band

insulator

solid material with no electrons in the conduction band and a large energy gap between the valence and conduction bands

valence band

the highest occupied band containing electrons. The band containing electrons with the highest energies and still be associated with a particular atom of a solid material

conduction band

The first unfilled band above the valence band, allowing the electron to dissociate from a particular atom and become a free charge carrier in the material

capacitance

the ratio of electric charge to potential difference between any two conductors separated by an insulating material. The capacitance of a system of conductors describes the ability of the system to store electric charge

capacitor

two (or more) conductors separated by an insulator that can be used to store charge

depletion layer

the area surrounding the p-n junction of a diode where the electrons have combined with the holes leaving no free charges

electric current

a net flow of charged particles

electromotive force

the electromotive force of a source is the electrical potential energy that is given to each unit of charge that passes through the source

forward-biased

a diode connected in a circuit such that the p-type terminal is more positive than the n-type terminal

frequency

the number of complete cycles of a wave passing a given point in a given time, usually per second. measured in hertz (Hz) where 1 Hz = 1 wave per second.

fundamental unit of charge

the magnitude of charge carried by one electron or one proton. Equal to 1.60 x 10-19 coulombs

instantaneous

at one point in time or at one particular instant in time

internal resistance

the opposition to current in a source of electrical energy

leakage current

the tiny current in a reverse-biased diode

load resistor

the resistor, or combination of resistors, that forms the external part of an electrical circuit

lost volts

the potential difference that is used to drive a current through the internal resistance of a source. given by the expression Ir where r is the internal resistance of the source

monochromatic

one energy, one frequency, one wavelength, one colour

ohm's law

the current in a conductor at constant temperature is directly proportional to the potential difference across it

open circuit

a circuit in which the current is zero. In the circuit there is a gap or an infinite resistance

period

the time to make one complete wave. measured in seconds

photodiode

a type of p-n junction diode that responds to light intensity

photovoltaic mode

the mode of operation of a photodiode where it can supply power to a load. This is the basis of a solar cell

potential divider

a circuit consisting of a number of resistors (often only two) in series, connected across a supply, that is used as a source of fixed or of variable p.d

p-type semiconductor

semiconductor material that has an excess of free holes

resistance

the opposition that a conductor offers to a current through it. Defined as the ratio of potential difference across the conductor to the current through it