The Science

•Electromagnetic induction :- The phenomenon of production of electric current in a coil, when the magnetic flux linked with the coil is changed is called electromagnetic induction.  •Magnetic flux :- Magnetic flux is a measure of number magnetic field lines passing through same surfaces.  It is a scalar quantity. It is denoted by  Φ. •Unit of magnetic flux :- SI unit of magnetic flux is weber (wb).    For normal field to surface                Φ=BS When B=1T            S=1m² Then               Φ=1T m²              =1weber.  •Weber:- The magnetic flux with a surface are of 1 m² held normally in a magnetic field of 1T is called one weber.      Cgs unit of Φ is maxwell(Mx).                Φ=BS If B=1 gauss ...

1.Diamagnetic substances :- The substances which are feebly magnetised in a direction opposite to that of the magnetising field when placed in it are called diamagnetic substances.  Examples:- Bismith, Antimony, copper, gold, murcury, water, alcohol, air, hydrogen, etc are called diamagnetic substances.  2.Paramagnetic substances :- The substances which are feebly magnetised in direction of the magnetising field when placed in it are called paramagnetic substances.  Example :- Aluminum, platinum, chromium, manganese, copper sulphate, Crown glass etc are some of paramagnetic substances 3. Ferromagnetic substances :- The substance which are strongly magnetised in the direction of magnetising field in which they are placed are called ferromagnetic substances.  Examples:- Iron, cobalt, nickle and a few of alloys

Biat savart's law:- According to the Biot-Savart law, magnetic field dB due to current element dl, at a point P situated at distancer from the current element Idl is: i) directly proportional to the current element Idl.   ii) directly proportional to the sine of the angle (θ) between current element and r,  iii) inversely proportional to the square of the distance r between current element and the point dB∝Idl (sinθ)/r2 dB = (μo/4π)×Idl×(sinθ)/r2 dB = Idl × r / r3

What is magnetism?  The property of a substance to attracting small pieces of iron, steel and some other substances is called magnetism.  Magnet:- The substance which exhibits property of attracting small pieces of iron, steel and some other substances is called magnet. Natural magnet:- The minerals which exhibits property of magnetism are called natural magnets.  Artificial magnets :- Man made magnets convenient for practical purposes are called artificial magnets.  Magnetic poles:- The regions near ends of a magnet where the property of attraction is most prominent are called magnetic poles. Axis  of magnet:- A line joining the poles of a magnet is called axos of the magnet  Magnetic length :- The distance between the true position of length of north and South poles is called magnetic length (NS)  Geometric length :- Length  of a magnet is called it's geometric length. Magnetic dipole and mag...

•Kirchoff's First law (kcl):- It states that the algebraic sum of current meeting or leaving a point is always zero. It is also called functional rule. •Example:- Consider a point N in an electric circuits in which current I1, I2, I3, i4 and I5 passing through resistances. Applying Kirchhoff's law I1+I2-I3+I4-I5=0 •Kirchoff's second Law (kvl) :- In a loop the algebraic sum of the emf's is equal to the algebraic sum of products of the resistance and the respective current passing through it. It is also called kirchoff's voltage law.  •Example :- •Some important board exam level question answers :- Q. 1) Write Kirchhoff's First law  ? Ans:-  It states that the algebraic sum of current meeting or leaving a point is always zero. It is also called functional rule. Q. 2) Write Kirchhoff's second Law  ? Ans:-  In a loop the algebraic sum of the emf's is equal to the algebraic sum of products of the resis...

Capacitor and It's Expression (Electrostatics)   What is capacitor?  An arrangement for storing large amount of electric charge in small space is called capacitor.  Principal of capacitor :- A capacitor works on the principal, "The capacity of an insulated charged conductor is increased appreciate by bringing near it an earth connected, unchanged  conductor Definition of capacitance :- Capacitance of a conductor may be defined as the ratio of the electric charge on it to it's electric potential due to that charge                              C=Q/V Expression for parallel plate capacitor :- Let the two plates are kept parallel to each other separated be a distance d and cross-sectional area of each plate is A.   We konw that,                     C= Q/V According to the gauss law, the electric fie...

Conductors, insulators and Dielectrics  (Electrostatic)   • What is conductor ? Conductors are the Materials or substances which allow electricity to flow through them. They conduct electricity because they allow electrons to flow easily inside them from atom to atom. Also, conductors allow the transmission of heat or light from one source to another. Metals,humans, earth,  and animals are all conductors. This is the reason we get electric shocks! Moreover, the human body is a good conductor. So it provides a resistance-free path for the current to flow from wire to body. Conductors have free electrons on its surface which allow current to pass through easily. This is the reason why conductors are able to conduct electricity . Example :- • Material such as silver is the best conductor of electricity. But, it is costly and so, we don’t use silver in industries and transmission of electricity. • Copper, Brass, Steel, Gold, and Alumini...