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Flashcards in Electricity And Forces Deck (41):

How does static electricity build up?

When charges are not free to move many of them build up, this results in a large charge when the charges finally move it causes a spark


What are the masses and charges of sub atomic particles

Proton + and 1 mass
Neutron no charge and 1 mass
Electron 1/2000 mass and negative charge


How does static build?

When two insulating materials are rubbed together electrons will be scraped off one and dumped on the other giving the one with dumped electrons a negative charge and the other positive


When electrons move from a duster to a polythene rod what charges to both take

The polythene rod becomes negative
The duster becomes positive


Common places static electricity is found

When synthetic clothes are dragged over each other like in a tumble dryer electrons are scraped off leaving static charges on both.
Car seats can rub against your clothes creating static you can get a shock when touching the metal handle.


Why does a static balloon stick

The negative balloon repeals the negative electrons on the wall leaving only positive charge which attracts therefore it sticks


Describe uses of static electricity

Spray paint gives the paint a static charge. When it sprays the negative charges push the paint away creating an even coat and the paint is also attracted to the object as it is given the opposite charge.


How do you stop static charges.

Use a conductor to ground the charge.


What is current

The rate of flow of charge


Why are metals good conductors

Because they have free electrons which can carry charge


How to calculate charge

Charge is current x time


What is voltage

It is the driving force that pushes the current round it can be though of as electrical pressure


What is resistance

Anything in the circuit which slows down the flow of charge measured in ohms


What is potential difference

It is the same as voltage
It is the energy transferred per unit of charge passed


What is 1 volt equal to

1 joule or coulomb


What happens at a junction in a parallel circuit

The current is split up depending on the resistance, but none is lost it is the conservation of energy


How to calculate potential difference or voltage

Current x resistance


What is the relationship between resistance and voltage

The resistance is proportional to the voltage at a constant temperature


What happens to a filament lamp as the temperature increases

The resistance also increases


Describe a LDR in different types of light

In bright light the resistance falls
In dark light the resistance increases
In bright light to stand out a sign needs to be as bright as possible so the resistance must be low


Describe a Temperature Dependant Resistor in different temperatures

In hot conditions the resistance drops
In cool conditions the resistance increases


Why do resistors get hot under high energy transfer

Because the electrons collide with ions in the lattice as they move through, these collisions give the ions extra energy emitted as heat. The heat increases the resistors resistance if it becomes to hot no current will flow. It can cause components to melt, this is how fuses work they melt when the current or voltage becomes to high.


What is electrical power

The rate at which an appliance transfers energy
It is calculated by potential difference x current


What is the difference between a vector and scalar

Both are measurements but a vector has a direction, for example displacement or velocity


How do you calculate time



What is acceleration and give the unit

The rate at which the velocity is changing, is is useually measured in m/s squared


What is the formula for acceleration

V-U. Change in velocity divided by time taken
A x T


In a distance time graph what is the gradient



In a velocity time graph what is the gradient what do flat sections represent

Acceleration , a constant speed represented by flat sections


How to calculate distance in a velocity time graph

The area under the graph


How are forces shown

Through arrows, the larger the arrow the larger the force the direction of the arrow shows the direction of the force


What will a car with a constant speed force arrows be like

They will be exactly the same as the forces either side are balanced so it is in equilibrium


What is the force of gravity



What is the difference between weight and mass

Weight is the gravitational pull caused by gravity on your mass.
Mass is the amount of stuff you are


All objects in a vacuum do what

Fall at the same rate as there is no things to slow the items down such as air resistance and the pull of gravity is equal so they fall at the same rate


What is terminal velocity

The point of which the force pulling something down is the same as the force of air resistance and others such as drag, this causes the speed to become constant and no acceleration to occur.


What is a resultant force

The force that occurs which is in direct opposite to the force first acted I.e. Object A exerts a force on object then object ab exerts the exact opposite force on object A


What happens when the resultant force is zero

The thing will continue doing as it did I.e continue at a constant velocity


What happens if the resultant force acting on a body is not zero

They object will accelerate in the direction of the resultant force


How do you calculate force

Mass time excels ration


What type of current do cells and battery's supply

Direct current