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Electricity & Megnetism

Maxwell’s equations:Derivation in integral and differential form

4 Maxwell equations The basic equations of electromagnetism which are collection of Gauss’s law for electricity ,Gauss’s law for magnetism ,Faraday’s law of electromagnetic induction and Ampere’s law for currents in conductors are called Maxwell’s equations. These equations are part of comprehensive and symmetrical theory of electromagnetism,which is essential to understand electromagnetic waves,optics,radio and TV transmission,microwave ovens and magnetically levitated ...

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Resistance in series and parallel circuits

Combinations of resistance in electric circuit There are two possible combinations of resistance in electric circuits: Series combination Parallel combination Series combination In series combination,resistors are connected end to end and electric current has a single path through the circuit.This means that the current passing through each resistor is the same. The current is the same through all points in ...

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Inductance of a toroid formula derivation and examples

What is toroid? The solenoid bent into circular shape is called toroid. Inductance of a toroid derivation Consider a toroid having rectangular cross sectional area.The inner radius of the toroid is ‘a’ while outer radius is b.The number of turns of toroid is N.Let i be the current flowing through each turn of toroid. The magnetic field lines inside the ...

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chemical effects of electric current

Chemical effects of current Voltmeter or coulomb meter: The vessel in which electrolytes is carried out.It is also called electrolytic cell. Electrolyte: An ionic compound in aquas solution or molten state is called an electrolyte. Electrolysis: On passing current through an electrolyte,chemical changes occur in electrolyte and substances are liberated at the electrodes.This process is called electrolysis. Faraday’s laws: First ...

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Energy stored in a capacitor equation derivation and problems

Energy stored in capacitor equation Consider a capacitor with the capacitance ‘C’ ,which is connected to the battery of emf ‘V’ .If ‘dq’ charge is transferred from one plate to other,then the work done ‘dW’ will be: dW =V dq This work done is stored in the form of electric potential energy ‘dU’ dU =V dq When the capacitor is ...

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capacitance with two different dielectrics equation

Capacitance with dielectric formula Consider a parallel plate capacitor which is connected with a battery of emf ‘V’ .Let ‘A’ is the area of each plate and ‘d’  is separation between the plates. If ‘q’ charge is stored in the capacitor when there is vacuum or air as medium between the plates ,then: q= CV Where ‘C’ is the capacitance ...

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formula for total capacitance in series and parallel combination

Formula of equivalent capacitance in series Series combination when capacitors are connected in series,the total capacitance is less than the smallest capacitance value because the effective plate separation increases.The calculation of total series capacitance is analogous to the calculation of total resistance of parallel resistors. This type of combination has the following characteristics: Each capacitor has the same charge across ...

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thermister temperature sensor with types and applications

Thermistor definition A thermistor is a type of  variable resistor that is temperature sensitive . How thermistor works? When its temperature coefficient is negative,the resistance changes inversely with temperature. When its temperature coefficient is positive the resistance changes directly with temperature. The resistance of a photo-conductive cell changes with a change in light intensity.This cell also has a negative temperature coefficient. Symbols for ...

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What is difference between step up and step down transformer?

Step up transformer: If (Ns greater than NP) and (Vs is greater Vp) such a transformer in which voltage across secondary is greater than the primary voltage is called a step up transformer.A step up transformer has more turns in its secondary winding than its primary winding and is used to increase the ac voltage. The turns ratio for a step up ...

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what is Difference between induced emf and induced current?

  Induced EMF and Induced Current There are many ways to produced induced emf figure illustrated one of them. Consider a straight piece of wire of length l placed in the magnetic field of a permanent magnet. The wire is connected to a sensitive galvanometer. This forms a closed path or loop without any battery. In beginning when the loop  ...

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