7 Fields and their consequences Flashcards
(24 cards)
Force Field
Any region of space where a body will experience a non contact force.
Gravitational Field
A region of space where a mass experiences a force due to the gravitational attraction to another mass
Newton’s Law of gravitation
The gravitational force between two point masses is proportional to the product of their masses and inversely proportional to the square of their separation.
Gravitational Potential
The work done per unit mass in bringing a test mass from infinity to a point
Escape Velocity
The minimum speed that will allow an object to escape a gravitational field with no additional energy input
Synchronous orbits
When an orbiting body has a time period equal to that of the body being orbited and in the same direction of rotation.
Coulomb’s Law
The electrostatic force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of their separation.
Electric Field Strength
The force per unit charge experienced by a small positive test charge placed at that point
Electric Potential
The work done per unit charge in taking a small positive test charge from infinity to a point.
Capacitance
The charge stored per unit potential difference between plates. Measured in Farads
Permittivity
The measure of how easy it is to generate an electric field in a certain material. (Example is permittivity of free space.)
Gravitational Field Strength
The Force per unit mass on an object in a gravitational field.
Relative permittivity
Also known as dielectric constant. The ration of the permittivity of a material to the permittivity of free space.
Time constant of a capacitor
The time take for the charge, current, or voltage of a discharging capacitor to decrease to 37% of its original value.
Magnetic Field
A regional of space where a magnetic pole will experience a force.
Magnetic Flux Density
The number of magnetic flux lines passing through a region of space per unit area
1 Tesla
The flux density that causes a force of 1N on a 1m wire carrying a current of 1A at right angles to the flux
Magnetic Flux
The product of the magnetic flux density and the cross sectional area perpendicular to the direction of the magnetic flux density
Magnetic Flux Linkage
The product of magnetic flux and number of turns of a coil
Electromagnetic Induction
The process in which emf is induced in a circuit due to a change in magnetic flux
Faraday’s Law
The magnitude of the induced emf is directly proportional to the rate of change of magnetic flux linkage
Lenz’s Law
The induced emf acts is such a direction to produce effects that oppose the change causing it
Alternating current
A current which periodically varies between a positive to a negative value with time
The rms of an alternating current
The equivalent direct current value that will produce the same power
