sp8 Flashcards
(28 cards)
what is power
the rate at which energy is transferred
measured in watts
power=work done/time taken
what is a force field
the space around an object where it can affect other objects
why is a contact force
objects interact by exerting forces on each other. if the the forces are touching then the forces between them are contact forces
what is gravity
a force that occurs between any two objects that have mass
what is a magnetic field
the space around a magnet where it can affect other materials
what is an electric field
an object charged with static electric
he electric field can affect objects around it.
two objects with the same charge that are close with each other a pair of forces that are equal in size acting in opposite directions.
what is an a amperes
what electric current is measured in. often shortened to amps.it uses an metre that that is connected to a series to mesquite the current passing through it.
what are the 2 different types of current
There are two types of
current direct and alternating. In a direct current, the flow of electrons is consistently in one direction around the circuit, in an alternating current, the direction of electron flow continually reverses.
what is a moment
A turning effect of a force. is the turning effect of a force. Moments act about a point in a clockwise or anticlockwise direction. The point chosen could be any point on the object, but the pivot. - also known as the fulcrum - Is usually chosen.
measured in newton meters
want is potential difference
Potential difference (or voltage) is a measure of energy, per unit of charge, transferred between two points in a circuit. A potential difference of 1 volt means that 1 joule of work is done per coulomb of charge.
the bigger the potential difference across the component the bigger the current
what is electric current measured in
coulombs. one coulomb is the charge that passes a point in a circuit when there is a current of 1 amp for 1 second
what is a magnetic material
one that is naturally attracted to magnets and can become a magnet
how do you make a temporary magnet
you have too bring a magnetic material to a magnet as long as there together its a temporary magnet
what are the two types of current
Direct current (DC) – when the electrons flow in one direction around a circuit.
Alternating current (AC) – when the direction of the electron flow continually reverses.
how is current measured
in amps using an ammeter
what is an electric current
An electric current is a flow of charged particles. In metal conductors the charged particles are free electrons. The electrons are free to move from one ion to another and a net flow of these electrons in one direction is an electric current.
how to measure the size of electrical current
amount of charge that passes a point per second.
equation charge=current x time
charge is measured in colons
U=I x T
what is the equation for potential difference
current x resistance
v=I x r
what is a series circuit
1.in a series circuit the same current flows through all the different electrical components so the current and all parts of the circuit are the same
2.the total potentiel différence is shared between all the electrical components
the total resistance of all components in a series circuit is the sum of the resistance of each component
what is the equation to work out the total resistance of multiple components in a Series cell circuit
resistance total = the sum of all the individual resistances added together
what its static electricity
Electric charge that accumulates on an insulated object, for example because of friction.
what does a van de Graf generator do
A Van de Graaff generator removes electrons to produce a positive charge. A person does not have to touch the Van de Graaff generator to start feeling the effects, as static electricity is a non-contact force . This force will act on any charged particle in the electric field around the generator.
A person touching the dome of the Van de Graaff generator will also lose electrons and become positively charged. The same will happen to each of their hairs. Since the person, their head, and each of the hair follicles are all positively charged, the hairs will repel from the head and from every other strand causing them to stick out from the head in all directions.
what is shown on an electric field diagram
Fields are usually shown as diagrams with arrows:
The direction of the arrow shows the way a positive charge will be pushed.
The closer together the lines are, the stronger the field and the greater the force experienced by charges in that field. This means that the field is stronger closer to the object.
what would DC look like on a voltage time graph and what provides DC
On a voltage-time graph this would appear as a straight horizontal line at a constant voltage.
Car batteries, dry cells and solar cells all provide a direct current (dc) that only flows in one direction.
