# ocr physic p1 p2 p3

size of atom
0.1nm
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dalton
positive ,dense sphere
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J.J. Thomson
- discovered electons - suggested electrons are embedded in atoms like plum pudding.
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Ernest Rutherford
-discovered the nucleus- fired alpha particles through a thin sheet of gold.expected the alpha particles to shoot straight through. however, some bounced back. this is called alpha scattering. -atom contain something positively charged
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Bohr
electrons are found in shells and travel in orbits. - has spaces between each shells
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mass and charges in atoms
- nucleus nearly contain all the mass - atoms form together by electric forces (molecules) -gases, particles are very weak causing them to spread out- gases have lower density than solids
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density
density(kg/m ) = mass(kg) / volume(m )
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changes of state
-physical changes, they're reversible -mass is conserved -sublimating (solid-gas), condensation (gas - liquid), freezing (liquid - solid), melting (solid- liquid), evaporation (liquid- gas)
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specific latent heat
-the amount of energy to melt a substance SLH= energy (joules) / mass (kg)
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specific heat capacity
- the energy needed to raise the temperature of 1 kg by 1 degrees - change in energy = mass x SHC x change in temperature
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gas pressure
-pressure exerts on all walls of the box -molecules bombard the walls -faster particles, bigger the pressure - pressure is related to temperature -smaller box: closer particles, wall are hit more frequently, more pressure
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kinetic energy
kinetic energy (j) = 0.5 x mass (kg) x speed squared (m/s)
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speed
distance traveled (m) = speed (m/s) x time (s)
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velocity
velocity= displacement/ time
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acceleration
acceleration (m/s/s) = change in velocity (m/s) / time (s)
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contact/ non-contact force
-force is a vector -contact force: friction acts parallel to the surface of the object - non-contact force: two magnets can attract or repel each other without touching , electric force is without touching
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net force
-overall force is called resultant or net force - when there's a net force it always accelerates - no net force the forces are balanced - the idea is called newton first law
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direction of force
- same direction you add - different direction you take away - pushing an object, you experience the same size force in the opposite direction
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newtons laws 1st
newton first law- if forces are balanced the object remains stationary -if the forces of the object moving is balance it will remain at constant speed
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newtons laws 2nd
- unbalance forces produces an acceleration - The bigger the unbalanced force the bigger the acceleration. This law is usually written as an equation: F = ma
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newtons laws 3rd
concerns equal and opposite forces. It states that, "If A exerts a force on B, then B exerts an equal but opposite force on A."
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circular motions
an object moving in a circular path with constant speed has a changing velocity,because its always changing direction
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momentum
momentum (kgm/s)= mass (kg) x velocity (m/s) - its a vector
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collision momentum
total momentum before = total momentum after -its conserved
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inertia
Inertia is the resistance of any physical object to a change in its state of motion
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work done
workdone= energy supplied= force x distance (m)
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potential energy
potential energy (j) = mass (kg) x height (m) x gravitational field strength (n/kg)
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energy stored and transfers
energy is stored as : kinetic , gravitational, elastic, thermal energy - energy transferred = charge (c) x potential difference (v)
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power
power (w) = work done ( energy transferred)(j) / time (s) power=
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extension and compression
- forces acting inwards on an object can compress it - change of shape is called deformation
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elastic and plastic deformation
-when a force makes an object change shape but returns to original shape the deformation is elastic - if object keeps its new shape its plastic
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extension of string
force exerted on a spring (n) = extention x spring constant
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weight
weight= mass x gravitanional field strength
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electrostatic phenomena
-friction can transfer electrons from one object to another: -one object will have lots of electrons making it negative charge - other object will have a shortage of electron making it positive charge
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electric current
-use an ammeter to measure current - metals are conductors of electricity - current = charge flow / time
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gravitational potential energy
= mass x gravitational field strenght x height
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efficiency
output energy transfer / time power output / time
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energy transferred
power x time
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energy transferred
charge flow x potential difference
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power 2
=potential difference x current
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power 3
= (current) squared x resistance
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potential difference
= current x resistance
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charge flow
=current x time
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magnets
-Bar magnets are permanent magnets. This means that their magnetism is there all the time and cannot be turned on or off -When a piece of unmagnetised magnetic material touches or is brought near to the pole of a permanent magnet,- induced magnet
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magnetic field (solenoid)
A solenoid is a long thin spiral of wire used to produce a magnetic field.
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fleming's left hand rule
thumb- force or movement first finger-field second finger- current
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relationship between work done and kinetic energy
wd=ke
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graphs
..
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diode
A diode is a component that allows current to flow in one direction only
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thermistor
At low temperatures, the resistance of a thermistor is high, and little current can flow through them. At high temperatures, the resistance of a thermistor is low, and more current can flow through them.
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LDR
In the dark and at low light levels, the resistance of an LDR is high, and little current can flow through it. In bright light, the resistance of an LDR is low, and more current can flow through it.
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## Other cards in this set

### Card 2

#### Front

positive ,dense sphere

dalton

### Card 3

#### Front

- discovered electons - suggested electrons are embedded in atoms like plum pudding.

### Card 4

#### Front

-discovered the nucleus- fired alpha particles through a thin sheet of gold.expected the alpha particles to shoot straight through. however, some bounced back. this is called alpha scattering. -atom contain something positively charged

### Card 5

#### Front

electrons are found in shells and travel in orbits. - has spaces between each shells