Question

The amount of work done in joules, when one-unit electric charge moves from one point to another point in an electrical circuit is called
(a) electric current
(b) electric conductance
(c) electric resistance
(d) potential difference

Answer 1

Hint: Scrutinizing the basic definitions of the given options, we can arrive at the correct answer easily. Work done between two points can be related to the difference in energies between these points. Electric circuits also follow the same concept wherein work done between two points in the circuit measures the difference in voltages of those points.

Complete answer:
The work involved or the energy released in the transfer of a unit quantity of electricity from one point to another is termed as potential difference between those points. The SI unit of potential difference is $volt(V)$. Clearly, a potential difference of $1V$ between two points in an electric circuit is defined as $1J$ of work done in bringing $1C$ of charge from one point to the other. Mathematically, this is given by
$1V=1J{{C}^{-1}}$
Potential difference between two points in a circuit is usually measured using a voltmeter.

Therefore, the correct answer is option (d).

Additional information:
Electric current: Electric current is defined as the continuous flow of electrons in an electric circuit is called as electric current. It is represented by $I$ and has its SI unit as $ampere(A)$.
Electric conductance: Electrical conductance of a component in an electric circuit measures the intensity of permission granted for electric charges to flow through that component. Electrical conductance is represented by the symbol $G$ and has its SI unit as $siemens(S)$ or $mho({{\Omega }^{-1}})$.
Electric resistance: Resistance of a component is a measure of the opposition put forth by the component to the current flow through it. It is usually represented as $R$ and has its SI unit as $\Omega $.

Note:
$1V$ can also be defined as the product of unit current and unit resistance in an electric circuit, according to Ohm’s law. Mathematically, this is given by
$1V=1A\times 1\Omega $
It is also to be noted that potential difference is sometimes called voltage, electric pressure or electric tension.