Question

Volt is the SI unit of
a) potential difference
b) capacitance
c) electric power
d) resistance

Answer 1

Hint: To define the unit of volt to a particular physical quantity we need to express volt in its fundamental dimension. The unit volts in the fundamental dimension can be written as $kg{{m}^{2}}{{s}^{-2}}{{C}^{-1}}$. Hence will define each of the quantities given to us in the options, express them in fundamental physical quantities and accordingly see the units matches with the unit of volts.

Complete answer:
To begin with let us first define the potential difference.
The potential difference is defined as the region of influence of charge where in work has to be done to move a unit positive charge across the region. This statement can be mathematically written as,
$V=\dfrac{W}{q}....(1)$ where W is the work done and q is the charge moved across the potential difference V. The SI unit of work done is $kg{{m}^{2}}{{s}^{-2}}$ and the unit of charge is coulomb(C). hence substituting these units in equation 1 we get,
$\begin{align}
  & V=\dfrac{W}{q} \\
 & V=\dfrac{kg{{m}^{2}}{{s}^{-2}}}{C}=kg{{m}^{2}}{{s}^{-2}}{{C}^{-1}} \\
\end{align}$
Hence from this we can conclude that the unit volts is the SI unit of potential difference.

So, the correct answer is “Option A”.

Note:
Capacitance has its standard unit equal to Farad. One farad is the ratio of one coulomb to that of the one volt. Electric power is defined as the product of voltage times the current. The SI unit of power is given by $Kg{{m}^{2}}{{s}^{-3}}$. The resistance in a circuit is the ability to reduce or stop the flow of current in the circuit. The Si unit of resistance is given by $V/A$ where ampere(A) represents the current in the circuit.