Question

Which is the S.I. unit of resistance?
A) Newton
B) Watt
C) Ohm
D) Joule

Answer 1

Hint: We know that resistance is the hindrance offered by an object to the flow of current through it. Lower is the flow of current higher is the resistance of a given material , hence we can say current is inversely proportional to resistance as according to ohm's law.

Complete solution:
We know that, The electrical resistance of an electrical conductor is the opposition to the passage of an electric current through that conductor.
The resistance of a conductor is said to be 1 ohm if 1 ampere current flows through it when the potential difference across its end is 1 volt. So, the S.I unit of electrical resistance is the ohm (Ω) which is defined as a volt per ampere.

According to Ohm's law, we can define it as the resistance of an object is defined as the ratio of voltage across it to current through it. We can write it as a mathematical form that is $R = \dfrac{V}{I}$ .

Hence, the correct option is C.

Additional information:
Joule is the unit of work or energy, in the International system of units we can define it as equal to the work done by a force of one Newton acting through one metre. Its SI based unit is $kg.{m^2}.{s^{ - 2}}$ .

Note:
The SI unit of force is the newton, its symbolic representation N. Means it is equal to the amount of net force required to accelerate a mass of one kilogram at a rate of one meter per second squared. The watt is a unit of power; its symbolic representation is W. It is defined as a derived unit of 1 joule per second and is used to quantify the rate of energy transfer.