Physics

- A wave is a movement of energy (without moving matter)

1)Transverse:
-Particles vibrate at 90 deg. to the direction of wave propagation
E.g. waves on water and light waves

2) Longitudinal Waves:
-Particles vibrate parallel to the direction in which the energy is being transferred
E.g. vibrations and sound waves

Diagram:

Frequency: No. of complete cycles of the waves which pass a point in one second (Hz)

Wavelength: Distance between one peak and the next (M) A wave with a long wavelength has a low freq and vise-versa.

Amplitude: Height from one centre line to the top of a peak(M). A high amplitude means that the wave is carrying more energy

Time Period:Time taken for one full cycle of a wave to pass a point (S) 

Diagram:

Diagram:

Diagram:

When light reflects from the surface of a plane mirror, the angle of incidence is equal to the angle of reflection

Diagram:

The range of human hearing:
- Sounds ranging from 20Hz up to 20,000Hz. Sounds below 20Hz are called Infra sound- sounds above are called ultrasound

Uses of Ultrasounds:
-Conduct Medical Scans
- Break up kidney stones
-Clean delicate items such as watch mechanisms 

Diagram:

All
-Transverse Waves and travel at 300 000 000m/s

Radiotherapy:
Gammy rays are aimed at the tumour- the source is rotated so that only the circle tumour recieves a high dose (killed)

- flow of charged particles (electrons)
- Must be a complete circuit made from conducting materials (metals)
- Water can conduct electricity but only at high voltages

Can be detected by using a bulb, an LED or an ammeter 

In a series circuit the current is the same at all points

The current from the cells is split up around the loops on the circuit. The first current you measure is the total of the next 3 measurements.

Measure of difference in energy between two points in a circuit

The difference between voltage and current:
-Current is a measure of how many electrons pass a point in a second
-Voltage is a measurement of how much energy each electron has (This energy comes from being attracted to the + side of the cell and repelled by the - side)

Diagram:

Diagram:

Resistance is a measure of how difficult electrons find it to flow through a circuit component. When the resistance is big, it is very difficult for electrons to flow and vice-versa. this means the bigger the resistance, the smaller the current (resistance is measure in ohms)

Sketch of the graph:

Conclusion:
> Relationship:
-The longer the length of wire, the bigger the resistance (directly proportional)

How can you tell?
-The shape of a line is a diagonal (slanted upwards)

Diagram:

Fuse:
-Safety devices
-Come in handy when a large unsafe current is flowing
-Get incredibly hot and melt- breaking the circuit

The Earth Wire:
- The earth wire is connected to the metal case of an appliance
-If a wire inside the appliance comes loose and touches the case, then the case is electrically live and could give the user an electric shock.
-Carries the current to the ground if a live wire touches the case
-The Earth wire has a low resistance and so a large current will flow and it will melt

Double Insulating:
- means the case is made of insulating plastic material 

1) Coal is crushed into dust

2) Coal dust is burned in a furnace

3) Water is heated to become steam

4) The steam burns in a turbine

5) The turbine turns a generator

6) Inside the generator a magnet and coil of wire produce electricity 

Coal Powerstations:

Chemical > Heat > Kinetic > Electrical

Hydroelectric Powerstation:

Gravitational P.E > Kinetic > Electrical 

Pumped storage are well suited to being used to sudden surges in the demand for electricity
> easily turn it on/off by opening/closing the gate 

Diagram: 

Area around a magnet which magnetic material experience a force.
> The lines are closer together where the magnet is stronger 
>Arrows show direction of the force on a magnetic North pole

Diagram of a Bar Magnet: 

Diagram of repelling: Like poles are repelling

When opposite poles are close then the fieldlines are straight/parallel/and equally spaced
> Magnetic field is of the same strength at all points 

Diagram: 

The right-hand grip rule: Direction of the field lines
> electric current flows through a wire, magnetic fields form around wire

Diagram:

- A magnetic field line cuts through a wire= a tiny voltage is induced
>If there is a complete circuit a tiny current will flow
> the size of the voltage ( and therefore current) depends on the number of magnetic field lines cuttign through the wire per second

We can make a bigger voltage by:
1) Having more fieldlines (ie stronger magnet)
2)Having more wires (e.g. by coiling up the wire or increasing no. of turns on wire)
3) Increasing the rate at which the magnet/wire moves

Table:

- groups of atoms with the same no. of protons in  the nucleus but different no. of neutrons
> same element but different mass

E.g. 

- isotope that is radioactive (because they have an unstable nucleus)
> can be because there are too many protons close to eachother in a large nucleus
> the nucleus throws parts of its self away to become more stable

Most things are slightly radioactive- but some are more than others
Natural resources of Ionising radiation:
>Rocks (especially graphite)
>The Sun
>Radon gas
>Cosmic Rays 

Artificial: Nuclear power stations> Nuclear fallout>Nuclear waste> Medical uses

Types of radiation: Table 

Examples:

Examples:

Examples:

>