External Flashcards
Define Colomb’s law
Like electric charges repel and opposite electric charges attract, with a force proportional to the product of the electric charges ad inversely proportional to the square of the distance between them. expressed by the formula
Define Electric Fields
Regions around an electrically charged particle or object within which a force would be exerted on other electrically charged particles or objects
Define Electric Field Stregth
The intensity of an electric field at a particular location
Define Electric Potential Energy
The capacity of electric charge carriers to do work due to their position in an electric circuit or the energy that is stored in an electric field when a charge is placed within that field
Define Electric Potential (V)
The work required per unit charge to move a positive point charge from infinity to a place in the electric field. V=dU/q which leads to V=W/q
Define Magnetic Field
A region of space near a magnet, electric current or moving electrically charged particle in which a magnetic force acts on any other magnet, electric current or moving electrically charged particle
Describe magnetic field lines caused by an electric current through a straight section of wire
the field lines are in concentric circles around the wire with the direction of the field in accordance to the right hand grip rule
What do crosses and dots mean on a 2D magnetic field diagram
Crosses show the field direction is ito the page and dots show the field direction is out of the page
What happens when a current carrying wire is placed in an external magnetic field and give the equation
The magnetic field created by the curret moving through the wire will experience a force with the external magnetic field
F=BILsin(theta)
what is I= to in reference to solenoids
number of loops/ length of wire
Define Magnetic Flux
a measurement of the total magnetic field that passes through a given area; a measure of the number of magnetic field lines passing through the given area
Define Magnetic Flux Density
The strength of a magnetic field or the number of magnetic field lines per unit area
Define electromagnetic induction
The production of an electromotive force or voltage across an electrical conductor due to its dynamic interaction with a magnetic field.
What is Faraday’s Law?
A law stating that when the magnetic flux linking a circuit changes, an (EMF) is induced in the circuit proportional to the rate of change of the flux linkage
What is Lenz’s law
States that the direction of an induced electric current always opposes the change in the circuit or the magnetic field that produces it
What is the formula for the force experienced by a charge moving through a magnetic field?
F=qvB
F is the force (N)
q is the electric charge on the particle
v is the component of the velocity of the particle that is perpendicular to the magnetic field
B is the strength of the magnetic field
Explain how Lenz’s law is consistent with the law of conservation of energy
Work is done to push the maget into the coil ad also to remove the magnet from the other end of the coil. As a result, a small amount of heat is produced from the current in the coil. Work done on the maget= heat energy from the current
Explain how transformers work in terms of Faraday’s law and electromagnetic induction
Faradays law states that a change in magnetic flux is required to induce an emf. A changing flux can be caused by an alreting voltage in the primary coil of the transformer (like solenoid with iron core). The changing flux is carried by the iron core ring of the transformer to the secondary coil where according to Faradays law, the changing flux iduces and emf on the secondary coil.
Define magnetic flux
The product of the magnetic field strength (B) and the area perpendicular to the field lines
formula for magnetic flux when at an angle to the field lines
flux= BAcos(theta)
theta is the angle between a normal to the area and the direction of the magnetic field.
