BMAT physics knowledge

A collection of physics notes for section 2 of the BMAT

HideShow resource information
  • Created by: aus159
  • Created on: 31-10-15 11:39
Preview of BMAT physics knowledge

First 252 words of the document:

Static electricity
Insulating materials
Metals are good conductors , which means that electric charges move easily through them.
Materials such as plastic, wood, glass and polythene are insulators. This means they
do not allow electric charges to move through them. Some insulators can become electrically
charged when they're rubbed together.
Charged objects
How can you tell if an insulator is charged?
If a plastic rod is rubbed with a duster it attracts small pieces of paper.
When a balloon is rubbed on a jumper it can stick to a wall.
Some dusters are designed to become charged so that they attract dust.
Positive and negative charges
Objects can be positively charged, negatively charged or neutral (no charge).
A substance that gains electrons becomes n egatively charged, while a substance
that loseselectrons becomes positively charged.
When a charged object comes near to another object they will either attract or repel each
If the charges are the same - t
hey repel
If the charges are opposite - they attract
If one is charged and the other is not - they attract
Higher tier only
An atom is made up of two parts - a positively charged n
ucleus surrounded by negatively
charged electrons. In an uncharged (neutral) atom there are the same number of positive
and negative charges.
Page 1of 25

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

An atom
When an acetate rod is rubbed with a duster, electrons are transferred from the rod onto the
duster, making the rod positively charged.
Problems with static
Static is a nuisance when:
Dust and dirt is attracted to insulators such as TV screens and computer monitors.
Clothes made from synthetic materials often cling to each other and to the body, especially
just after they've been in a tumble drier.…read more

Page 3

Preview of page 3

Here's a taster:

Electric current
Electric current is a flow of electric charge. No current can flow if the circuit is broken - for
example, when a switch is open.
Measuring current
Current is measured in amperes (which is often abbreviated to a
mpsor A ). The current
flowing through a component in a circuit is measured using an ammeter. This must be
connected in serieswith the component.
Calculating current
The size of an electric current is the rate of flow of electric charge.…read more

Page 4

Preview of page 4

Here's a taster:

Calculating potential difference
The potential difference between two points in an electric circuit is the work done when a
coulomb of charge passes between the points.…read more

Page 5

Preview of page 5

Here's a taster:

Potential difference
When two or more components are connected in series, the total potential difference of the
supply is shared between them. This means that if you add together the voltages across each
component connected in series, the total equals the voltage of the power supply.
Circuit symbols
You need to be able to draw and interpret circuit diagrams.
Standard symbols
The diagram below shows the standard circuit symbols you need to know.…read more

Page 6

Preview of page 6

Here's a taster:

Series and parallel connections
You should know the difference between series and parallel connections in circuits.
Series connections
Components that are connected one after another on the same loop of the circuit are
connected in series. The currentthat flows across each component connected in series is the
Two lamps connected in series
The circuit diagram shows a circuit with two lamps connected in series. If one lamp breaks,
the other lamp will not light.…read more

Page 7

Preview of page 7

Here's a taster:

The National Grid
Electricity is transferred from power stations to consumers through the wires and cables of
the National Grid. When a current flows through a wire some energy is lost as heat. The
higher the current, the more heat is lost. To reduce these losses, the National Grid
transmits electricity at a low current . This needs a high voltage.
Power stations produce electricity at 25,000V. Electricity is sent through the National Grid
cables at 400,000V, 275,000V and 132,000V.…read more

Page 8

Preview of page 8

Here's a taster:

The coil to which the alternating voltage is supplied is called the primary coil or
primary winding. When an alternating potential difference is supplied the resulting
alternating current in the primary coil produces a changing magnetic field around it.
This changing field induces an alternating current in the secondary coil. The size of
the induced voltage resulting from the induced current in the secondary coil depends
on the number of turns in the secondary coil.…read more

Page 9

Preview of page 9

Here's a taster:

Stepdown Transformer
A step down transformer has less turns on the secondary coil that the primary coil.
The induced voltage across the secondary coil is less the applied voltage across the
primary coil or in other words the voltage is "steppeddown".
Transformers are very efficient.…read more

Page 10

Preview of page 10

Here's a taster:

The magnetic field is strongest at its poles. The field around a magnet can be
represented by lines with arrows on them. The arrows show the direction of the lines
of force. Each field line starts at the North Pole and finishes at the South Pole.
Magnets affect a wire conducting electricity; this is because an electric current in a
wire produces a magnetic field.…read more


No comments have yet been made

Similar Physics resources:

See all Physics resources »See all resources »