Revision notes on Electricity.

In a Series Circuit the current readings A , A , A are all the same proving that current does not get used up by components (the bulbs) in circuit, but flows through each one in turn. In a Parallel Circuit the current A splits up into A and A which then join up to give A where A =A +A =A .Again this proves that current does not get used up.

If an Electric Current flows through a Coil of Wire a magnetic field is Formed Around The Coil creating an Electromagnet which is a magnet that can be switched on and off. The magnetic field formed is very similar to a bar magnet and so one end of the coil becomes a north pole and the other end becomes a south pole. Increasing The Number Of Coils, Increasing the Electric Current And Placing a Peace of Iron Inside the Coil Increases the Strength of the Electromagnet.

Forces:

Air Resistance

This is the force that pushes against a moving object As It passes Through Air. As for friction , Air Resistance tries to Slow Down the moving object.

Forms of Energy:

Light - Energy given out by any hot object.

Sound - Energy created by any Vibrating Object. It produces when something vibrates backwards and forwards. Sound travels much slower then the light. Sound needs a material to travel through as it can't travel through the vacuum.

Electrical - (look up)

Thermal (Heat) - It contains in any warm or hot objects and depends on temperature and size.

Kinetic (movement) - Object has it when it moves. The faster it moves the bigger is the energy.

Chemical Potential - Contains in food and fuel. Food energy released when we respire in our cells, and the energy in fuel is released when it is burned.

Gravitational Potential - The energy an object has due to its high above the surface of the earth. A higher it up the bigger is the energy.

Elastic Potential - This is the energy stored due to stretching or compressing an object which has the ability to regain its original shape and size.

Energy:

Whenever energy is transferred from one form to another some is wasted - usually as heat and often sound which spreads out and can't be used again. Although the amount of energy measured in Joules to begin with is always Conserved, which means there is still the same amount of energy before and after transfer.

Light:

We can see Luminous Sources, because the light they give out enters our eyes. We can see Non-luminous Objects, because light from a luminous sources is reflected off them into our eyes.

Reflection of the light:

Light changes direction when it crosses a Boundary between one Transparent Material and another providing, they are different materials unless it meets the boundary at 90?.

MARY KORYAKINA 9B