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From laws for resistance there are two laws one for length is

Specific on resistance

Where R is the resistance of a conductor and L is the length.

Another is for cross section area is

specific electrical resistance Read more on Specific resistance…

Electromotive force and potential difference are not same. They have following differences below

Electromotive force

  1. What is electromotive force? The potential difference between the two terminals of a cell is called electromotive force in an open circuit.
  2. Electromotive force transmits current both inside and outside the cell.
  3. Electromotive force emf is the cause.
  4. Electromotive force is always greater than potential difference.
  5. Electromotive force creates potential difference entire the circuit.
  6. Electromotive force does not depend on the resistance of the circuit.
  7. Electromotive force remains constant.
  8. The part of the circuit where electrical energy is created from any other energy then that part contains the source of Electromotive force.

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The flowing of current through conductor produce heat. We are using this heat due to flow of current in our daily life as in electric iron, electric bulb, electric fuse, electric heater and more. Heating effect of electric current are below

(i) Electric iron: In an iron the upper part is grooved. In this groove a coil is placed. Mica as an insulator is placed between the metal part and the coil, so that there is no electrical connection between them. Mica is a bad conductor of electricity but it is a good conductor of heat. Due to the flow of current through the coil it becomes heated and the heat transferred to the metal part through mica. Finally the metal part becomes heated. Iron is used with the heating effect of an electric current.

(ii) Electric bulb: we see a thick metallic wire in the bulb. It is made of tangsten metal. In a glass vessel or bulb the tangsten wire is kept sealed. The glass bulb is filled with neutral gas or vacuum. Neutral gases are using now a days commonly. The tangsten wire is known as filament when the current flows through the tangsten wire or filament it becomes heated and emit of light. Due to the flow of current heating effect of an electric current used as the source of light.

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The difference between resistance and specific resistance are below


  1. The ratio of the potential difference between the two ends of a conductor to the current flowing through at uniform temperature is called resistance of that conductor.
  2. The unit of resistance is ohm (Ω).
  3. Resistance of conductor depends on its length, temperature, cross section area, material of the conductor.
  4. Resistance is related with a particular conductor.

  Read more on Difference between resistance and specific resistance…

In law of resistance length, cross section area resistively is the main term of this law.

There are two basic laws of resistance. The resistance formula is

(i)Law of length:  The resistance of a conductor is proportional to its length when the temperature, cross section area and its material is fixed.

If the resistance wire is R and the length is L.

Then mathematically

The law of resistance Read more on The laws of resistance…

For unguided media, transmission and reception are achieved by means of an antenna. For transmission, the antenna radiates electromagnetic energy into the medium (usually air), and for reception, the antenna picks up electromagnetic radiation waves from the surrounding medium. There are basically two types of configurations for wireless transmission: directional and omnidirectional. For the directional configuration, the transmitting antenna puts out a focused electromagnetic beam; the transmitting and receiving antennas must therefore be carefully aligned.

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Boolean algebra is a means for expressing the relationship between a logic circuit’s inputs and outputs.

Digital circuits called logic gates circuits can be constructed from diodes, transistors and resistors connected so that the circuit output is the result of a logic operation (OR.AND, NOT).

A truth table is a means for describing how a logic circuit’s output depends on the logic levels present at the circuit’s inputs.

The OR GATES is the first of the three basic Boolean operations to be learned. The truth table in figure-1 shows what happens when two logic inputs, A and B are combined using the OR operation to produce the output x.The table shows that x is a logic 1 for every combination of input levels where one or more inputs are1.The only case where x is a 0 is when both inputs are 0.

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Electricity introduction

We can easily say electricity is the foundation and key of modern civilization. Without electricity we can not think even about modern civilization. The extensive use of electricity and tremendous application is evident in our daily life. Every essential electronic machine fans, trains, trams, industries, factories are run by electricity. Our houses are lighted by it. Radio, television, telephone, computer etc. can work with electricity. Now the main question is what is electricity- energy or matter?

No matter is present in electricity.

So, it is clear that from definition electricity is form of energy.

Read more on Origin of electricity…