Question

Symbol for resistance
$ {\text{A}}{\text{. }}\Omega \\
{\text{B}}{\text{. }}\pi \\
{\text{C}}{\text{. r}} \\
{\text{D}}{\text{. Dn}} \\ $

Answer 1

Hint: We can define the resistance of a material as the obstruction offered by it to the flow of electric current through the material. It is directly related to the length of the conductor and inversely related to the cross-sectional area of that conductor. Ohm’s law relates voltage and current through the resistance of the material.

Complete step-by-step solution:
Let us understand what is meant by the resistance of a conductor. It is an obstruction offered by the material of a conductor to the flow of electric current through it. The expression for the resistance is given as
$R = \dfrac{{\rho l}}{A}$
Here the resistance of a material is directly proportional to the length l of the conductor and is inversely proportional to the cross-sectional area of the conductor while $\rho $ is known as the resistivity of a conductor which is the resistance offered by a conductor per unit length and per unit cross-sectional area. The units of resistance are ohms. Its symbol is omega ($\Omega $).
Hence, the correct answer is option A.

Additional information:
The ohm’s law for an electrical conductor is given as
$V = IR$
Here V is the potential difference applied across a conductor while I is the current produced in the conductor due to this potential difference.

Note: 1. It should be noted that the resistivity of a conductor is independent of the dimensions of the conductor and depends only on the material of the conductor. It is a constant proportional between the resistance and the length and cross-sectional area of the conductor.
2. The symbol $\pi $ is used to signify pi while r can be used to signify quantities like radius.