physics paper 1

Define the term power

Rate at which energy is transferred or work is done.

mA → A

%1000

Km→m

X 1000

Cm→m

%100

nm→m

%10x*-9

ŲA→ A

%10*-6

MJ→J

X 10*6

GJ→J

X10*9

Power units

Watts

Kinetic energy units

Joules

Gravitational potential energy unit

Joules

Weight units

Kg

Work done units

Joules

Hight units

Metres

Mass units

Kg

Gravity units

N/kg

Speed units

m/s

Define the term density

The mass per unit volume of a material

Units of density

Kg/m3

Define upthrust

The upward force exerted by a fluid on an object submerged in it.

Define internal energy

The sum of the kinetic energy and potential energy of all the particles

Why doesn’t the temperature change when substances are changing state?

Because energy is used to either break or make bonds so it stays constant.

Units of specific latent heat

J/kg

What is latent heat

The energy needed to change the state of 1kg of a substance without changing temp.

What is the latent heat of fusion

Energy needed to melt/freeze

What is latent heat of vapourisation

Energy needed to evaporate/condense.

What is Brownian motion

When larger particles are moved randomly because other particles bump into it and push it around. In fluids .

Define pressure

The force acting on a surface per unit area

What happens to pressure when temp. Increases

Particles gain kinetic energy which means they move faster and collide more frequently with the container walls and with more force making the pressure increase.

What happens to pressure as volume increases

Pressure decreases as it is inversely proportional. Because the particles have less space to move around so there are more frequent collisions with the container walls.

What is the specific heat capacity

The amount of energy needed to raise the temperature of 1kg of the sun stance by 1*c

Units units for specific heat capacity

J/kg*c

What is a conduction

The transfer of heat by particles colliding with each other

What makes a good insulator

Any material with air trapped in it e.g. feathers , polystyrene

5 ways to insulate houses

1) have a cavity wall filled with foam or trapped air.

2) carpets /underlay

3) draught excluders

4) double glazing- traps gas’s between glass

5)loft insulation-fibre glass ,reflects IR

How to calculate payback time

Payback time = insulation cost / annual saving

Describe the greenhouse effect

1)short wave radiation from the sun comes into earths atmosphere

2)earth emits long wave radiation

3) gases in the atmosphere trap some outgoing long wave radiation-heating the atmosphere.

4) some long wave radiation leaves the atmosphere.

What can you measure levels of radioactivity with

Geiger counter

Units of radioactivity

Sieberts

Define background radiation

Radiation that is always present around us , very low levels.

Where does background radio come from

Rocks underground

Cosmic rays From space

Food& drink

Medical resources like x-rays

Advantage of using natural gas instead of coal

Doesn’t release sulfur dioxide so doesn’t cause global dimming , acid rain.

Definition of an isotope

Elements with the same number of protons and different numbers of neutrons

Features of radioisotopes

Heavy,unstable

Decay to become more stable by emitting radioactivity particles.

Who discovered radioactivity

Henry Becquerel and Mary Curie

what was JJ. Thompsons atom model

Plum pudding - positive body whithe negative electrons embedded randomly. It don’t have free space

What was Earnest Rutherford atom model

Alpha scattering experiment. Fired alpha particles at a gold sheet , discovering the nucleus is a dense ,positive mass at the centre of the particle with mostly empty space around it .1/8000 alpha particles were deflected instead of going through

Bohrs particle model

Had electron shells orbiting the nucleus .shells were at set distances from the nucleus.

Define irradiation

When an object is exposed to ionising radiation. The object does not become radioactive.

Define ionisation

Any process which atoms become charged

Define contamination

The unwanted presence of materials containing radioactive atoms on other materials. This is due to the decay of the contaminating atoms.

Mass of alpha

Heavy

Speed of alpha

Slow

What is alpha stopped by

A few centimetres of air

Paper

Skin

Charge of alpha

+

Ionising strength of alpha

Highly ionising

Source that emits alpha

Americium

Mass of beta

Light

Speed of beta

Fast

What is beta stopped by

1m air

3mm aluminium

Charge of beta

-

Ionising strength of beta

Medium

What does beta do to magnetic fields

Strongly deflects them

What is beta emitted by

Strontium

What is gamma emitted by

Colbalt

Mass of gamma

0

Speed of gamma

Speed of light - 3×10*8

What is gamma stopped by

3cm lead

1m concrete

Charge of gamma

Neutral

Ionising strength of gamma

Weak

How to be safe handling ionising radioactive sources

Use to tongs

Wear a lead lined apron

Don’t point the source at someone

Limit dose/contact

Hazard symbols

Symbol for alpha decay

4. 🐠

Symbol for beta decay

0

-1. ẞ

Gamma decay

0

0. Y

Define half-life

The time it takes for half of the radioisotopes/ radioactive nuclei to decay.

Half life

Nuclear fission

The splitting of a heavier nucleus into 2 lighter nuclei and the emitting of energy and 2/3 neutrons.

Happens in power stations , chain reaction .

Has carbon control rods which absorb neutrons to stop chain reactions

Nuclear fusion

The joining together if light nuclei to make a heavy nucleus. Hydrogen+hydrogen=helium

Happens in stars needs a high pressure and high temp.

What happens to mass after fusion

It is less than the individual nuclei added together before. Some mass is converted into energy.

Is nuclear power a fossil fuel

No

Is nuclear power non-renuable

Yes

Compare fission and fusion

Fission- splitting of nuclei , neutron needed to start it, happens in nuclear power stations , produces a lot of energy, produces radioactive waste, no CO2 produced , produces gamma radiation.

Fusion- joining id 2 nuclei to form a new nucleus, needs 1000*c and high pressure, happens in stars, produces even more energy, no harmful products, no CO2 produced, produces gamma radiation.

What do opposite charges do

Attract

What do like charges do

Repel

What happens if you make friction between 2 insulators

Electrons can be transferred onto or off an object causing a build up of static charge.

What happens if I rub a polythene rod with a cloth

The rod is negatively charged

The cloth is positively charged

What happens if I rub a Perspex rod and a cloth

Cloth becomes negatively charged

Rod becomes positively charged

How do electric field lines look in positive charge

Lines from all sides of the ball with arrows facing away from it

Electric field lines on a negative ball

Lines with arrows pointing inwards

Draw a diode

Draw a resistor

Plain box

Draw a variable resistor

Draw a light emitting diode

Draw a light depended resistor

Where do you add an ammeter to a circuit

In series

Where do you add a voltmeter in a circuit

In parallel

What happens to a bulb if you increase the potential difference in parallel

Gets brighter

Define current

A flow of charge

What is conventional current

First belief of electricity - positive to negative

Current in series

Equal everywhere

TotalA = A1 =A2