Part 2 Chapter 1 -Electricity and Magnetism Flashcards
It is when attraction takes place
Magnetism
Magnetic Quantities
- Magnetic Flux
- Flux Density
- Magnetomotive Force
- Magnetic Field Intensity
- Reluctance
- Permeance
Counterpart of Current in Electricity
Magnetic Flux
Counterpart of Voltage in Electricity
Magnetomotive Force
Counterpart of Resistance in Electricity
Reluctance
Counterpart of Conductance in Electricity and also a reciprocal of Reluctance
Permeance
What is the Formula of Magnitude of Flux in a Surrounding Straight Conductor
Phi = 14x10^-8 I(l) log R/r
What is the Formula of Magnetic Flux Density
B = Magnetic Flux / Area
Discovered the relationship between magnetism and electricity that serves as the foundation for the theory of electromagnetism
Hans Christian Oersted
Demonstrated the theory of electromagnetic induction in 1831
Michael Faraday
Developed the electromagnetic theory of light in 1862
James clerk maxwell
He discovered that a current carrying conductor would moven when placed in a magnetic field
Michael Faraday
Discovered the most important electrical effects which is magnetic effect
Hans Christian Oersted
Demonstated that there are magnetic effects around every current carrying conductor and that current carrying conductor can attract and repel each other just like other magnets
Andre Ampere
Discovered superconductivity in 1911
Kamerlingh Onnes
Magnitude of the induced EMF in a coil is directly proportional to the rate of change of flux linkages
Faraday Second Law of Electromagnetic Induction
Whenever the flux linking a coil or current changes an emf is induced in it.
Faraday First Law of Electromagnetic Induction
The force pf attraction or repulsiob between two magnetic pole is directly proportional to their strenghts
Coulombs First Law
The force of attraction or repulsion between two poles is inversely proportional to the square of the distance between them.
Coulombs Second Law
Whenever a conductor cuts magnetic flux an EMF induced in it
Faraday’s Law
A Law that states the the POLARITY OF THE INDUCED VOLTAGE will oppose the change in magnetic flux causing the induction
Lenz Law
A law that states that the current in the thermionic diode varies directly with the three-halves power of anode voltage and inversely with the square of the distance between the electrodes, provided operating conditions are such that the current is limited only by the space charge
Child’s Law
States that the ratio of the thermal conductivity to the electric conductivity is proportional to the absolute temperature for all metals
Wiedemann-Franz Law
A law that establishing the fact that the algebraic sum of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero
Ampere’s Circuital Law
The “net electric charge” in an “isolated system remains constant “
Law of Conservation of Charge
Lenz law is the consequence of the law of conservation of
Energy
Lenz law states that the direction of the induced emf and hence the current
Always oppose the cause producing it
If you hold the conductor with right hand so that the stretched thumb points in the direction of the current then encircling fingers will give the direction of magnetic lines of force
Right Hand Rule
If a right handed bottle-opener cork screw is assumed to be along the conductor so as to advance in the direction of current flow , the motion of its handle will indicate the direction of magnetic flux produced around the conductor
Cork Screw Rule
If on looking at any one END of a solenoid , the direction of current flow is found to be clockwise then the end under observation is a south pole this is known as
End Rule
Is the solenoid is gripped by the right hand with the fingers pointing the direction of current flow, the outstretched thumb will then point the north pole
Helix Rule
The process by which an emf and hence current is generated or induced when there is a change in the magnetic flux linking the conductor
Electromagnetic induction
The emf induced in a coil due to the change of its own flux linked with it is called
Self Induced EMF
The EMF induced in a coil due to the changing current of another
Mutually Induced EMF
When a conductor is stationary and the magnetic field is moving or changing the emf induced is called
Statically Induced EMF
The magnetic potential in a magnetic circuit can be measured in terms of
Magnetomotive force
A substance that attracts pieces of irol
Magnet
The phenomenon by which a substance attracts pieces of iron
Magnetism
Which of the following is a natural magnet
Lodestone
Defined as the pole which when placed in air from similar and equal poles repel it with a force of 1/4pi(uo) newtons
Unit Pole (k)
The point in a magnet where the intensity of magnetic lines of force is maximum
Magnetic Pole
The straight line passing through the poles of a magnet is called
Magnetic Axis
The branch of engineering which deals with the magnetic effect of electric current is known as
Electromagnetism
The space outside the magnet where its poles have a force of attraction or repulsion on a magnetic pole is called
Magnetic Field
The total number of magnetic lines of force in a magnetic field is called
Magnetic Flux
The phenomenon by which a magnetic substance becomes a magnet when it is placed near a magnet
Magnetic Induction
Magnetic materials can be easily magnetized in both direction
Soft Magnetic Materials
Which of the following materials has a permeability slightly less that that of free space
Diamagnetic
Materials whose permeabilities are slightly greater than that of free space
Paramagnetic
Materials that have very high permeabilities (hundreds and even thousand times that of free space)
Ferromagnetic
The current of the electric circuit is analogous to which quantity of a magnetic circuit
Flux
What is the diameter of an atom?
About 10^-10 m
defined as a closed path in which magnetic induction or flux flows
Magnetic Ciruit
the force which sets up or tends to set up magnetic flux in a magnetic circuit
magnetomotive force
