physics paper 1

topics 1-4 : energy, electricity, particle model of matter, atomic structure

John Dalton description of atom (3)

(1804)

-solid neutral ball

-atoms of one element are all alike but differ from atoms of other elements

-atoms cannot be subdivided,created or destroyed

JJ Thompson description of atom

(1904)

-solid neutral ball of positive charge with electrons stuffed in it

-called the plum pudding model

discovered the electron in 1897

Ernest Rutherford description of atom

(1911)

mostly empty

nucleus is very small - concentrated positive mass

Ernest Rutherfords Alpha particle experiment

ER tested JJs Plum Pudding model in 1908.

In the experiment Alpha particles were fired at a thin sheet of gold foil.

Some alpha particles went straight through-meaning the atom was mostly empty.

Some of the Alpha particles were deflected- meaning there’s a positive mass in the center of the atom- ER called the nucleus

order of being discovered and who

proton

neutron

electron

electron - jj thompson 1897

proton - Ernest Rutherford 1917

neutron - James Chadwick 1932

similarities of plum pudding model and rutherfords model (2)

-both are neutral

-both have electrons

differences of plum pudding model and rutherfords model

-JJs model is solid whereas Rutherfords is mostly empty

-JJs doesn’t have a nucleus

isotope

an atom with the same number of protons and a different number of neutrons

radioisotope

an isotope that’s unstable and will emit radioactive decay to become stable

alpha decay

what it’s made of,

charge, how big,

mass,

range in air,

stopped by,

how penetrating,

how ionising

made up of two protons and two neutrons- same as helium nucleus

charge= 2+,

relatively large,

mass= 4,

range in air=5cm,

stopped by= paper,

low penetrating,

high ionising

beta decay

what it’s made of,

charge,

how big,

mass, range in air,

stopped by,

how penetrating,

how ionising

made up of an electron

charge=-1,

mass=1/2000,

range in air=1m,

stopped by=mms aluminium,

medium penetrating,

medium ionising

gamma decay

what it’s made of,

charge,

how big,

mass,

range in air,

stopped by,

how penetrating,

how ionising

are electromagnetic waves

charge=0,

mass=0,

range in air= >km,

stopped by=thick lead,

high penetrating,

low ionising

alpha decay question

14/6 C

14/6 C → 10/4 Be + 4/2 alpha particle

beta decay question

14/6 C

14/6 C→ 14/7N+ beta particle (0/-1 e’)

gamma decay question

14/6 C

14/6 C→ 14/6 C +Gamma ray

activity of a source

number of nuclei that decay per second measured in Becquerel (Bq)

count rate of a source

amount of radiation detected per second by a machien called a geiger-mullertube

ion

an atom with either more electrons than protons or the other way round

half life

amount of time it takes for half the radioactive nuclei to decay

contaminated

something that has absorbed radioactive material

irradiated

something that has absorbed some ionising radiation

activity equation

number of decays emitted/time(s)

ionising radiation

radiation that has enough energy to remove electrons from an atom.

background radiation

the radiation that is present all around the environment

fission

when large unstable nuclei will split into 2 smaller stable nuclei

fusion

where two smaller nuclei come together to form one larger nuclei-this releases lots of energy

electric charge

property of materials or particles (just like mass or size)

what is current

-current = amount of coloumbs that pass a point in 1 sec

-metals contain delocalised electrons which move randomly

-when a battery/power source is attached to a metal wire in a complete circuit the delocalised electrons move from neg to pos

-this flow of electrons are the current

-charge is measured in coulombs - 1 Coulomb = 6.24 × 10^8 electrons

charge flow equation=

charge flow (Q)= Current (I) x Time (t)

Q in coulombs (C), I in amps (A), t in secs In equation triangle (Q) at top

series circuit

current?

Voltage?

where all components are in the same loop

-current is the same everywhere

-voltage shared between the components

parrallel circuit

where components are in seperate loops

-current divided between branches or split

-voltage is shared between the branches

what do electrical circuits transfer

energy between stores

what do electrons (charged particles) carry

energy around a circuit

potential difference

difference in energy between 2 points- measured with voltmeter

1 volt =

1 joule of energy per coulomb of charge

potential difference equation

potential difference (V)= Energy (E)/ Charge(Q)

V measured in volts, E measured in Joules, Q measured in coulombs

in equations triangle E on top

resistance

how difficult its for current to flow through a compound

measured in Ohms

how is resistance caused

delocalised electrons coliding with metal ions

what type of wire has a high resistance

low resistance

long and thin

short and thick

potential difference resistance equation

potential difference (V)=Current(I) X Resistance(R)

V measured in volts, I measured in amps, R measured in Ohms

in equations triangle V on top

ohmic resistor

resistor following ohms law (resistance doesnt change with temp)

so potential difference and current are directionally proportional to each other

what type of gradient has a low/ high resistance

steep gradient- low resistance

shalow gradient-high resistance

power,current and resistance triangle

power on top

power, pot dif and current triangle

power on top

difference between alternating and direct current

(direction electrons move,safer,types of electric)

AC’s electrons move in alternating directions whereas DC’s cureent moves in 1 direction

DC is safer

AC is a type of mains electric

frequency and pot. dif. of mains electric

50Hz (changes direction 50x per second)

230V

why can you get an electric shock if you touch an object that becomes live?

as an electric current passes through you and to the earth and the pot.dif between you,earth and charged object completes the circuit

how does the earth wire prevent you from getting an electric shock

earth wire has low resistance route for the current to reach earth. resistance route is lower than traveling through your body the current passes through the earth wire not you

what does each wire and fuse do in a UK plug

green+ yellow stripes (top)

-is the earth wire

-is a safety feature-stops electric shocks

blue wire (left)

-is the neutral wire

-completes the circuit

is at 0 V

red wire (right)

-is the live wire

-carries the current to the device

fuse

-connects to red wire

-safety feature-breakes when currents too high

explain each component of the national grid

power station→(electricity leaves)→step-up transformer(pot.dif increases) transmission cables (low current means less energy is lost from heat) →step-down transformer (pot.dif decreased to 230V)→consumer

what would a graph of light intensity against resistance look like

why?

resistance on y axis, light intensity on x axis- line of best fit would be diagnoal left to right with slight drop

as light intensity increases current increases, because there is less resistance

how should you structure a 6 marker when describing an experimant

equiptment

set up

readings

data analysis (only 6 markers)

what is power

when thinking about circuits what is it

whats it measured in

the rate of energy transfer

when thinking about circuits power is the rate of electrical transfer

measured in watts (W)

what does conservation of energy tell us

that energy can never be created or destroyed

whats the potential difference between the neutrala and live wire

230V

give 2 differences between alternating supply and direct supply

• alternating supply doesnt have a consistant voltage

• alternating supply changes the direction of its current

resistance

everything that resists or opposes the flow of electrons in a circuit

In 'conventional current', we say that the electrons flow from:

Positive terminal ➔ negative terminal

potential difference

the force driving the flow of electrons around a circuit

current

a measure of the flow of electrons around a circuit

whats this diagram is a current / voltage graph for

fixed resistor

For wires and resistors, increasing the temperature will __________ the resistance.

increase

The above diagram is a current / voltage graph for a:

filament lamp

diodes

allow the current to flow in 1 direction

The above diagram is a current / voltage graph for a:

diode

charge

a measure of the total current that flowed within a period of time

diode

fuse

light dependant resistor

thermistor

variable resistor

fixed resitor

The resistance of a thermistor decreases when the temperature _______.

increases

The resistance of a light dependent resistor decreases when the light intensity _______.

increases

In a series circuit, the potential difference of the battery is:

Shared across all of the components

In a series circuit, the total resistance is ________ the sum of the individual resistances of each component.

equal to

In a series circuit, components with a greater resistance will always have a ________ share of the voltage.

greater

what is the current between all paralell loops

shared

The of the current in each loop is equal to the total current.

what is it and what does it do

light emitting diode (LED)

emits light when current passes through

what is thais and what does it do

light dependant resistor (LDR)

detects light levels

what is this and what does it do

fuse

breaks a circuit if theres a fault and too much current to flow- makes it safe

Electric fields can be shown with electric field lines.

Field lines always point from:

pos to neg charge

what is a thermistor

a resistor whos resistance decreases when temperature increases

whats a light dependant resistor (LDR)

a resistor whos resistance decreases when light intensity increases

solids

distance between particles

bond between particles

motion of particles

particle diagram

very close

very strong

vivrate

liquids

distance between particles

bond between particles

motion of particles

particke diagram

very close

strong

slide past slowly

gases

distance between particles

bond between particles

motion of particles

particle diagram

far apart

none

very fast, random directions

movement of partciles

what particles have the same and which one js different

simmilar

liquid and gases- can move from place to place

different

soldi- only vibrate

closeness of particles

what particles have the same and which one is diff

simmilar

solids+liquids-as particles are very close

differnet

gasses-particles are very far apart

bonds between particles

what particles have the same and which one is diff

simmilar

solids+liquids-particles are very strong

different

gasses-particles have no bonds holding them together

explain why can gasses be compressed but liquids and solids can’t (5)

-solids liquid particles are close together

-when compressing a solid or a liquid there is no space

-gas particles are far apart

-when compressing a gas there is space to be compressed together

-you cannot compress liquids or solids

explain why gases fill their containers but their liquids and solids cannot have a fixed volume (5)

-a gas bond between particles is none

-so a gas spreads out to fill the container

-a solid or a liquid’s bond between particles is strong

-so when a solid or liquid is in a container the particles stay together

-liquids and solids don’t fill their container/ change their volume

whats a solid turning into a liquid called

whats a liquid turning into a gas called

whats a solid turning into a gas called

melting

boiling

sublimation

whats a gas turning into a liquid called

whats a liquid turning into a solid called

whats a gas turning into a solid called

condensing

freezing

deposition

true or false

temperature describes the average kinetic energy movement of the particles in a substance

True

why will the particles move slower in a cup of tea left on a table in a cold room

particles average temp will decrease

so the average kinetic energy decrease

so the particles move slower

why will the particles vibrate faster in an ice cube left out in the sun on a hot summers day

temp of the ice cube will increase

so the kinetic energy will increase

therefore the particles will move faster

true or false

when bonds between particles are broken the particles loose potential energy

false

bonds between particles are broken the particles potential energy

so

bonds between are made the particles loose potential energy

what state of matter do particles have

thw most potential energy

the least potential energy

gas

solid

does the substance gain or loose potential energy when

a substance melts/boils

a substance freezes/condenses

bonds are broken so substance gains potential energy

bonds are made so the substance looses potential energy