Magnetism Flashcards
Unit of magnetic field
Tesla
The number of magnetic field lines passing through a given area
Magnetic flux
Unit of magnetic flux
Weber wb
The number of magnetic field lines crossing unit area kept normal to the direction of field lines is called
Magnetic flux density
Unit of magnetic flux density wb/m2
The current carrying conductor produce magnetic field around it is demonstrated by
Hans Christian oersted
Who found that a charge moving in a magnetic field in a direction other than the direction of magnetic field experiences A Force
H a Lorentz
It is called the magnetic Lorentz force
In 1821 who discovered that the current carrying conductor also get reflected when it is placed in a magnetic field
Michael Faraday
1 When the conductor is parallel to the magnetic field the force will be
2 when it is parallel to the magnetic field the force will be
Maximum
Zero
F= BIL
B MAGNETIC FIELD
I CURRENT
L. LENGTH OF THE CONDUCTOR
The angle of inclination between the current and magnetic field also affect the magnetic field
Force is always a vector quantity
Fleming left hand rule is also known as
Motor rule
The direction of current is denoted by the middle finger of the left hand and the second finger is for direction of the magnetic field then the thumb of the left hand denote the direction of force or movement of the conductor
Three fingers of left hand in perpendicular to each other
To change the direction of current in DC motor a small device called
Split ring commutator
The speed of rotation of coill can increased by
Increase in the strength of current in the coil
increase in the number of terms in the coil
increase in the area of the coil
increasing the strength of the magnetic field
In which year Michael Faraday explained the possibility of producing EMF across the conductor when the magnetic flux linked with the conductor is changed
1831
The phenomenon of producing an induce EMF due to change in the magnetic flux linked with a closed circuit is known as
Electromagnetic induction
The direction of the induced current was given by
Lenz law state that the induced current in a coil flows in such a direction has to oppose the change that causes it. கம்பிச்சுருளில் தூண்டப்பட்ட மின்னோட்டமானது அது உருவாக காரணமாக இருந்த காந்தபாய மாற்றத்தை எதிர்க்கும் என்பது லென்ஸின் விதி ஆகும்
The direction of induced current can also be given by another rule called flemings right hand rule
Michael Faraday main discoveries
Electromagnetic induction diamagnetism, electrolysis
Fleming right hand rule is also called
Generator rule
Middle finger direction of induced current (direction of current in left hand rule)
Thumb finger indicates direction of motion of conductor(direction of force or moment of conductor in left and rule)
Fore finger direction of magnetic field
Transformer work on the principle of
Electromagnetic induction
Formula of transformer
Np/Ns = Vp/Vs = Is/Ip
Transformer cannot be used with the direct current source
Because the current in the primary coil is constant in DC. Then there will be no change in the number of magnetic field lines linked with the secondary coil and hence no EMF will be induced in the secondary coil
The magnetic field setup by a current carrying conductor is always at _________ to the direction of flow of current
Right angle
