Unit 5 & 10 Flashcards
one Coulomb
the charge transported by a current of one ampere in one second
Electric field
a region where a charged object experiences a force.
Electric field strength
the force per unit charge experienced by a small positive point charge placed at that point.
Coulomb’s Law
The force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between their centers. The direction of the force is along the line connecting the two charges.
Current
the rate of flow of charge.
Direct Current
current that flows in just one direction.
Potential Difference
the energy transferred from one coulomb of charge moving between two points in a circuit.
Electromotive force
the energy transferred to electrical energy per coulomb of charge.
Electron Volt
the energy transferred to an electron when it moves through a potential difference of one volt = 1.6*10^-19 J
Kirchoff’s first law
the sum of the current into a junction equals the sum of the currents away from a junction.
Kirchoff’s second law
in a complete circuit loop, the sum of the EMFs in the loop is equal to the sum of the potential differences in a loop.
Ohm’s law
the PD across a metallic conductor is directly proportional to the current in the conductor providing that the physical conditions of the conductor do not change.
Primary Cell
an electric cell that produces current by an irreversible chemical reaction.
Secondary Cell
a rechargeable electric cell that converts chemical energy into electrical energy by a reversible chemical reaction.
The capacity of a cell
a measure of the ability of a a cell to release charge = the constant (ish) current * the time it can supply this for.
Flemmings left-hand rule
Thumb = movement
First finger = field
Second finger = current
(mother fucking cunt)
Right-hand rule
Fingers = field Thum = current
Gravitational field
a region of space where a massive object experiences a force.
Electrostatic field
a region of space where a charged object experiences a force.
Electric potential
the work done per unit charge in moving a small unit positive test charge from infinity to that point.
Gravitational Potential
the work done per unit mass in moving a small test mass from infinity to that point.
Newton’s Law of Gravitation
the force of attraction between two massive objects is proportional to the product of the masses and inversely proportional to the square of their separation.
Field Line
A line used to show the direction of a field. (for electric field it shows the direction a positive charge would move)
Equipotential Surface
A surface of constant potential. The work done to move a charge from any point on the equipotential surface to any other point on the equipotential surface is zero since they are at the same potential.
Electric Potential Energy
Energy a charged object possesses because of its position in an electric field
Gravitational Potential Energy
Energy a massive object possesses because of its position in a gravitational field
Potential Gradient
The change in potential divided by the distance over which the change happens.
Potential Difference
the difference of electrical potential between two points.
Escape Velocity
the lowest velocity which a body must have in order to escape the gravitational attraction of a particular planet or other objects.
Geosynchronous orbit
an orbit with a time period of 24 hours so the satellite appears to stay in the same region of the sky
Polar orbit
an orbit close to the Earth’s surface that often goes over the poles
Geostationary orbit
a special case of the geosynchronous orbit where the satellite orbits around the equator so will be stationary relative to the Earth.
Orbital energy
The sum of the potential and kinetic energies of an object in orbit
Uniform Field
A field where the electric field strength is constant throughout the field.
Radial Field
A field that is drawn from a central point and becomes weaker as the distance from the point increases.
