Definition of Electricity, Current, Charge and Important Facts

What is Electricity

Electricity is the set of physical phenomena associated with the presence and flow of electric charges. That is, it can neither be seen nor touched, it can be felt only through its effect. Well-known phenomena are associated with electricity such as lightning, static electricity, electromagnetic induction, and electric current. In addition, it is possible to create and receive electromagnetic waves (such as radio waves) only through electricity.

What is static electricity

In about 600 BC (BC), the Greek philosopher Thales observed that when amber was rubbed with a cat's skin, it had the property of attracting small pieces of paper etc. . Although this small experiment itself did not have any special significance, but in fact this experiment can be considered the birth of the modern electric age. This discovery did not attract any attention until two thousand years after Thales. In the 16th century, Dr. Gilbert, a contemporary of Galileo, who was at that time a domestic physician to Queen

Elizabeth of England,

Testified that amber and many other things like cat skin—for example, glass and silk and lac and flannel—when interacted with each other. If they are rubbed in, they also have the property of attracting small objects. This type of electricity obtained by friction is called

Frictional electricity

It is also called static electricity, provided that the charge generated by rubbing the substances on them remains constant where they are generated by rubbing.

What is electric current

The flow of charge is called electric current. The flow of charge in solid conductors is due to the transfer of electrons from one place to another, whereas in liquids such as aqueous solutions of acids, bases and salts and gases, this flow is due to the movement of ions. Ordinarily, the direction of electric current is considered to be towards the direction of motion of positive charge and opposite to that of negative charge. The direction of current in solid conductors is assumed to be opposite to the direction of flow of electrons.

Electric current and rules Electric current and rules:

The amount of electric current (measured in amperes) passing through a surface, such as a section of a copper conductor, can be defined as the amount of electric charge that has passed through that surface in that amount of time. If Q Coulomb of charge is released in time t through a cross-section of a conductor; So by taking the mean current measurement time t to zero (rending to zero), we get the instantaneous current i(t):

I = Q / t (if current is constant with time)

Ampere, which is the SI unit of electric current. The instrument which is used to measure the electric current of the circuits is called ammeter. Ampere Definition: In an electric circuit, 1 coulomb of charge flows in 1 second, then the value of electric current in that circuit is 1 ampere.

1. Example: 50 coulomb of charge flows in a wire in 10 seconds, then the value of electric current flowing in that wire is 50 coulomb / 10 second = 5 ampere

What is electric charge

It was discovered in 600 AD. The credit goes to Thales, a resident of Greece, the word 'electricity' is also derived from the Greek word electron which means 'amber'. Electric charge is a fundamental property in some subatomic particles that is the significance of electromagnetism. A charged substance has the effect of an electric field and can itself be the source of an electric field. Charge is a property of matter! When substances are rubbed together, the property of attraction comes due to the exchange of electrons between them.

Effects of Electric Current

Mainly the following effects of flowing electric current are- magnetic effect, thermal effect, chemical effect and optical effect.

Magnetic effect

Whenever an electric current flows through a conductor, a magnetic field is generated around the conductor. In 1812, Oersted, a resident of Copenhagen, discovered through an experiment that if a magnetic needle is placed near a current-carrying wire, it deflects. Since the magnetic needle deflects only in a magnetic field, it is clear that an electric current produces a magnetic field. This is called the magnetic effect of electricity. Directional Law of Magnetism: The direction of the magnetic field is given by Maxwell's cork-screw law, Palming's right hand law, etc.

Maxwell's Cock-screw Law

If a cork is taken in the hand of the screw and rotated in such a way that it moves in the direction of current, then the direction of motion of the thumb gives the positive direction of the magnetic lines of force.

Fleming's Right Hand Rule

If the thumb and the first two fingers are to be spread in such a way that they are at right angles to each other and if the forefinger is in the direction of the current and the middle finger Tell the deflected direction of the needle, then the direction of the thumb tells the direction of the magnetic force.

Lorentz Force

When a charged particle moves in a magnetic field, a force is applied to it, which is called the Lorenz force. This force is directly proportional to the charge of the particle, its speed and the intensity of the magnetic field. In physics (especially electromagnetism), the Lorenz force is a combination of the electromagnetic and magnetic forces acting on a point charge in an electromagnetic field. A particle moving with a velocity v of charge q experiences a force in the electric field and magnetic field B- [where q = charge of the particle, v = speed of the particle, B = magnetic field, = velocity of the particle v and the magnetic field The angle between B] The direction of the force F can also be found by Fleming's Left Hand Rule. If a charge q, velocity v enters an external magnetic field B, then a force is exerted on it perpendicular to both the direction of motion and the direction of the magnetic field is called Lorenz force. it as a vector-

1. F= qv × B

Electromagnet
If an insulated wire is wrapped around a cylindrical object, it is called a solenoid. A cylindrical object is called its core. A solenoid with a soft iron core is called an electromagnet. They are used in dynamo, transformer, electric bell, tele-communication, telephone, hospital etc. Temporary magnets are made from soft iron. The intensity of the magnetic field produced by an electromagnet depends on the following factors:

1. Number of turns of the solenoid: If the number of turns is more, then the magnetic field will also be strong.
2. Nature of core material: If the core is of soft iron, then the intensity of the magnetic field is high.
3. Magnitude of Current: The greater the magnitude of the current, the stronger the field.

Force on magnetic materials

Calculating the force on ferromagnetic materials is a complex task. The reason for this is that the sizes of objects etc. are different, due to which there is no simple formula to calculate the magnetic field in all situations. If you want to calculate its value more accurately, then Finite-Element method has to be used. But for some special situations, formulas for calculating magnetic field and force can be given. For example, look at the picture on the front. Here most of the magnetic field is confined to a material of high permittivity (eg, iron). The value of maximum force for this situation is as follows- where:

• F, Force (in Newtons)
• B, Magnetic Field (Magnetic Flux Density) (in Tesla)
• A, the area of the pole (in m²);
• , magnetic permeability of vacuum

Magnetic Flux: The total number of magnetic lines passing through a surface placed in a magnetic field is called magnetic flux of that surface. The SI unit of magnetic flux is Weber (wb).

Magnetic field: The definition of magnetic field is also given in the term of magnetic flux at a point i.e. magnetic flux passing through per unit area is called magnetic field of that point. The SI units of magnetic field are ampere/metre, tesla and bever.

Galvanometer: A galvanometer or galvanometer is a type of ammeter. It is used to detect the presence of current in a circuit. Often it is not marked with ampere, volt or ohm. It is used as an ammeter by putting a small value resistance (called a shunt) parallel to the galvanometer. It is used like a voltmeter by putting a large resistance of the appropriate value (it is a multiplier) in series with the galvanometer. With this instrument, electric current up to 10-6 amperes can be measured.

Ammeter: Ammeter or 'ampere' (ammeter or AmpereMeter) is a device for measuring the electric current flowing in a branch of a circuit. Devices used to measure very small amounts of currents are called "millimeters" or "microammeters". The earliest design of the ammeter was the D'Arsonval galvanometer or moving coil galvanometer.

Voltmeter: Voltmeter is a measuring instrument used to measure the potential difference between any two points of a circuit. Hans Orestad invented the voltmeter in 1819. When he made an electric current flow in a wire placed near the needle of a magnetic compass, he saw that its direction was changing. On paying attention it was found that the more ampere current is passed in the wire, the more rapid the change in the direction of the needle. For this reason his measurement was not coming right.

In the 11th century, Arsne d'Arsonval created an instrument that could measure better than the earlier instruments. For this he shortened the compass needle and surrounded it with a magnet from all sides. This is known as the d'Arsonval movement and is used in today's analog meters. In practice, voltmeters work like ammeters, which measure voltage, current and resistance as well.

Electrostatic-

Vital Facts About Electricity

1. The SI unit of resistance is ohm.
2. Watt is the unit of electric power.
3. The unit of coefficient of induction is Henry.
4. Electron volt is the unit of energy.
5. The unit of charge is the coulomb.
6. At 4k the resistance of mercury is zero.
7. Silver is the best conductor of electricity.
8. The unit of electric capacitance is Faraday.
9. The cadmium cell is called the authentic cell.
10. Lead is used in storage batteries.
11. The SI unit of electric current is the ampere.
12. The coil of the electric heater is made of nichrome.
13. The filament of an electric bulb is made of tungsten.
14. Fuse wire is made of lead and tin.
15. Kilowatt hour is the unit of electrical energy.
16. Low power bulb has more resistance.
17. Dynamo converts mechanical energy into electrical energy.
18. Dynamometer is an instrument to measure the power generated by the engine.
19. The value of alternating current is zero for one complete cycle.
20. The relative electronegativity of a substance is always greater than 1.
21. Nitrogen or some inert gas is filled in the electric bulb.
22. DC only from Weston ammeter. Electric current is measured only.
23. Oersted discovered the magnetic effect of electric current.
24. Ammeter is always connected in series with the electric circuit.
25. The voltmeter is always connected in parallel to the electric circuit.
26. Alternating current cannot be used for electroplating.
27. The resistance of the ammeter is very low and the resistance of the voltmeter is very high.
28. Electric current is carried from one place to another at high C voltage.
29. Copper is considered to be the best for making electric wire because it has an abundance of free electrons.
30. A step-up transformer converts low potential strong alternating current into high potential weak alternating current.
31. Transformer works on the principle of electromagnetic-induction. It is converted into the potential of C electric current.
32. Resistance is a property that opposes the flow of electrons in a conductor. It controls the magnitude of the electric current.
33. Resistance is a property that opposes the flow of electrons in a conductor. It controls the magnitude of the electric current.
34. The resistance of a conductor depends directly on its length, inversely on the area of cross section and also on the nature of the material of which it is made.
35. Ohm's law – The potential difference across a resistor is directly proportional to the current flowing through it, but one condition is that the temperature of the resistor should remain the same.
36. Even with the same power, a fluorescence tube gives off more light than an ordinary filament bulb, because the fluorescent material in the tube converts ultraviolet radiation into visible light.

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