Question

Name the unit of (a) electrical resistance (b) resistivity.

Answer 1

Hint: At first to know the units of electrical resistance and resistivity we need to know what is resistance and what is resistivity. We must know which factors they depend on and how they are calculated.

Complete step by step answer:
To know the unit of these two factors of electrical circuit, we need to know what these two factors actually are.
Now, resistance is actually the opposition of flow of current. That is when current is flowing through a body it gets some opposition to its free flowt his opposition to free flow of current is known as resistance.
Electrical resistance depends on, Length of the conductor, Cross-sectional area of the conductor and the temperature of the conductor.
Resistivity is actually the measure of how strongly a material opposes the free flow of electrons through the body itself. This factor is sometimes known as specific resistance of a conductor.
Resistivity for a material is generally a constant value that is it is constant for a material and yes unlike resistance it depends upon the dimensions of the sample.
Resistivity depends on the temperature of the conducting material.
We represent electrical Resistance with the unit of $\Omega $(Ohm).
We know that the if we represent resistance in dimensional form we will get, \[{{M}^{1~}}{{L}^{2~}}{{T}^{-3~}}{{I}^{-2}}\]
We represent Resistivity with units of $\Omega -m$(Ohm/meter).
And we can represent resistivity in dimensional form as $M{{L}^{3}}{{T}^{-1}}{{Q}^{-2}}$ .

Note:
Students must know what is resistivity and what is resistance. They obviously must know how resistivity and resistance work. To remember a unit we can do nothing without remembering the units there are no methods for calculating a unit. Students must show the dimensional forms of those units. And they must also know the factors on which they depend. In the dimensional form of resistivity, $M{{L}^{3}}{{T}^{-1}}{{Q}^{-2}}$, M is the mass of the body, L represents Length T represents the time and Q represents the charge in the body itself.