Electrical Resistance

Electrical Resistance

Resistance physics is an impediment to charge flow. An electron does not travel directly from terminal to terminal. It is a zigzag path instead, which is a result of innumerable collisions in the conduction material with fixed atoms. While the established electric potential difference between the two terminals stimulates charging movement, it is electrical resistance that discourages it.The conductor gives some barrier to the current when an electric current runs into a bulb or any conductor, and this obstruction is known as electrical resistance .

An object's resistance is mostly determined by the material it is made of. Insulators, such as rubber, have a very high resistance and low conductivity, whereas Electrical resistance of conductors, such as metals, have a very low electrical resistance and great conductivity.

Resistance Definition:

In an electric circuit, resistance could be a measure of the opposition to current flow.

Also read -

  • NCERT Solutions for Class 11 Physics
  • NCERT Solutions for Class 12 Physics
  • NCERT Solutions for All Subjects

What is electrical resistance? What is the meaning of resistance and resistance formula? Define resistance in Physics?

Resistance Definition Physics: Resistance meaning in physics is a measure of the opposition to current flow in an electric circuit (also known as ohmic or electric resistance). Ohm the unit of resistance denoted by the Greek character Omega (Ω). The greater the resistance, the greater the flow barrier.

The flow rate of the electrons and electric current are reduced due to colliding or obstacles. Therefore, we might say that the passage of electrons or current are opposed. This barrier to the flow of electric current offered by a substance is therefore called an electrical resistance.

The resistance of a conductor's is estimated to be

1. The electrical resistance of the material is directly proportional to the length of the material.

2. The electrical resistance of the material is inversely proportional to the material's cross-sectional area.

3. The electrical resistance of the material is dependent on the material's composition.

4. The temperature is a factor.

The resistance of a conducting substance can be stated mathematically as,

Rla

R=la

where,

R denotes the conductor's resistance.

l is the conductor's length.

a = conductor's cross-sectional area.

ρ = the material's proportionality constant, often known as its specific resistance or resistivity.

The Ohm is the unit of electrical resistance.

What Is Resistivity?

Electric resistivity is defined as the Electrical resistance offered per unit length and unit cross-sectional area at a given temperature. Specific Electrical resistance is another name for Electrical resistivity. Electrical resistivity is measured in ohms-metres, which is the SI unit.

Factors Affecting Resistance or Electrical resistance

The resistance of a conducting wire is caused by free electrons colliding in the conductor as they drift toward the positive end.

The electrical resistance of a material, such as a wire or conductor, is determined by the following variables:

1. The material's length.

2. The material's surface area.

3. Temperature.

Nature of the Material

  1. Conductors: The resistance of conductors is quite low. It's important to remember that copper has a very low resistance but a very high conductivity, which is why it's utilized as a connecting wire. Other conductors, such as gold and silver, can conduct electricity as well.
  2. Insulators: Insulators provide extremely high resistance.
  3. Pure semiconductors, which have an extremely high resistance, exist between the conductor and the insulator.
  4. Alloys: Manganin and Constantan alloys have low resistance; therefore their lower lengths are required to make standard resistances for wires of a particular diameter.

Temperature of the Material:

As a material's temperature rises, its thermal energy rises as well, causing ions/atoms in a conductor to vibrate at larger amplitudes and frequencies. The relaxation time decreases when the free electrons begin to wander towards the conductor's positive end. The electrical resistance of the conductor rises as a result of this.

Also check-

  • NCERT Exemplar Class 11th Physics Solutions
  • NCERT Exemplar Class 12th Physics Solutions
  • NCERT Exemplar Solutions for All Subjects