Question

Which one of the following is a fundamental unit
A. Ampere
B. Newton
C. Volt
D. Ohm

Answer 1

The units of fundamental quantities are known as fundamental units, it is defined by the International System of Units. These units are not dependent on any other fundamental units, and all the other units such as joule, watt everything is derived from them. Some of the fundamental units are meter, kilogram, second, mol, etc.

Complete answer:
Let us see each and every given option individually:

a.)Option A, Ampere.
Current is measured in Ampere, it is the base unit for measuring current and is accepted globally. This unit is named after Andre-Marie Ampere who was a French mathematician and physicist. Ampere is referred to as “Amp” in short.
One ampere current represents one coulomb of electrical charge.
So from the above explanation we can say that Ampere is a fundamental unit.

b.)Option B: Newton,
We all know that Newton is the unit of force.
One newton= 1 Kg m/s(1 kg meter per second)
Its dimensional Formula is: $\text{ }\\!\\![\\!\\!\text{ }{{\text{M}}^{1}}{{\text{L}}^{1}}{{\text{T}}^{-2}}\text{ }\\!\\!]\\!\\!\text{ }$
So we can clearly see that this is a derived unit.

c.)Now let us see,
Option C: Volt
Volt is a unit of electric potential or Electromotive Force (EMF).
So,
We know, that according to ohm’s law,
V = I R.
In dimensional form: V = Energy / Charge.
Dimensional formula for Joule/sec is:$M\text{ }{{L}^{2}}~{{T}^{-}}^{3}~{{I}^{-}}^{1}$.
From this we can conclude that it is also a derived unit.

d.)Now taking option D into consideration:
Option D: Ohm
Ohm is the SI unit of resistance, which is universally accepted.
We know that resistance is a derived unit:
Its dimensional unit is: $M{{L}^{2}}{{T}^{-}}^{3}{{I}^{-}}^{2}$
So Ohm is also a derived formula it is clearly seen from the above statements.

So, the correct answer is “Option A”.

Note:
One can question that 1 ampere = 1 coulomb/sec and second is a fundamental quantity then how ampere is a fundamental unit, we have to notice that ampere is a unit of electric current and not charge passed, and in the rules for fundamental units its written that if that unit is made up of two or more fundamental unit then only it can be called a derived unit or else it's also a fundamental unit.