physics paper 1

radio use

communication

microwave use

heating food

infrared use

night vision and thermal imaging

visible light use

seeing and taking pictures and videos

ultraviolet use

security marking and fluorescent bulbs

x rays use

x ray images

gamma rays use

sterilising medical equipment

microwave dangers

heat damage to internal organs

infrared dangers

skin burns

visible light dangers

eye damage

ultra violet dangers

sun burn and skin cancer

x ray dangers

kills cells/mutations

gamma dangers

kills cells/mutations

electromagnetic spectrum anogram

giant xylophones usually vibrate in my room

what occurs with voltage and current in a series circuit

voltage splits

current is the same throughout

what occurs with voltage and current in a parallel circuit

current splits

voltage is the same throughout

voltage

energy transferred per unit charge passed

current

rate of flow of charge

neutral wire

blue

live wire

brown

earth wire

green/yellow

circuit breakers vs fuses

breaks have a higher voltage and current

breaks are quicker

you can reuse a breaker

fuses are cheap

fuses are more straightforward to install

series circuit

all components controlled by one switch

wiring is more simple

current is same everywhere

if one component breaks the whole circuit fails

parallel circuit

each component is controlled independently

if 1 component breaks the whole circuit will work

voltage is same throughout

current can get to large if too many paths are added

principle of energy conservation

energy cannot be created or destroyed only transferred from 1 store to another

power

rate of doing work

radiation

energy is transferred by electromagnetic waves

conduction

vibrating particles transfer energy from kinetic energy store to kinetic energy stores of neighbouring particles

convection

more energetic particles move from hotter region to a cooler region and transfer energy as they do it

acceleration

rate of change of velocity

friction

a force that opposes motion

hookes law

extension is directly proportional to the force up to a limit of proportionality

elastic behaviour

the ability to return to its original shape once the force is removed

terminal velocity of a falling object

initially no air resistance

as it falls acceleration increases and so speed and air resistance increases

resultant force downwards decreases

acceleration decreases

eventually they are equal and opposite and so balance

resultant force = zero

no acceleration so terminal velocity is reached

black materials

good absorbers

good emitters

white/shiny materials

poor absorber

good reflector

how does a vacuum flask keep drinks warm

heat loss by convection is reduced as a vacuum dosen’t contain particles

heat loss by radiation is reduced by silvered shiny surface around flask

surface reflects infrared rays trying to escape flask

heat loss is reduced as the cap is made of insulating material/foam which traps air

hard magnets

stay magnetic when taken out of magnetic field

e.g. steel or cobalt

soft magnets

they lose magnetism easily

e.g. iron or soft iron core

dot on page

current coming out of page

cross on page

current going into page

solenoid

when a current flows in a wire it creates a magnetic field around the outside of the wire

by coiling the wire we can make this magnetic field strong

Flemings left hand rule

thumb = force

second finger = magnetic field

third finger = current

magnetic field

a region of space where a magnetic material feels a force

electromagnetism

when the flow of current causes a magnetic field

electromagnet

an insulated coil of wire on an iron core connected to a battery to allow a current to flow