Question

If the work is to take 5C electric charge from one point to another point is 20J, what will be the potential difference between these two points?
$\begin{align}
  & \left( A \right)3V \\
 & \left( B \right)15V \\
 & \left( C \right)5V \\
 & \left( D \right)4V \\
\end{align}$

Answer 1

Hint: Work done is defined as the product of charge and the potential difference between the two points. Here the values of work done and magnitude of the charge is given. Thus here the potential difference between the two points is the ratio of the work done to the magnitude of charge. Then by substituting those values we will get the value of potential difference.
Formula used:
Work done, $W=QV$
Where, Q is the magnitude of the charge
and V is the voltage or potential difference between the two points.

Complete step by step solution:
Given that Q=5C
W=20J
We have to find the potential difference.
Hence using the equation we get,
$W=QV$
Where Q is the magnitude of the charge
and V is the voltage or potential difference between the two points.
Rearranging the equation for potential difference between the two points we get,
$\begin{align}
  & V=\dfrac{W}{Q} \\
 & \Rightarrow V=\dfrac{20}{5} \\
 & \Rightarrow V=4V \\
\end{align}$

Therefore option (D) is correct.

Note:
The value of potential difference can either be positive or negative. That is, the sign of potential difference changes with the polarity of the current flow through the conductor. When a charge is placed at a point there will always be an electric field associated with it. Thus the voltage or potential difference can also be defined as the electrical work per unit charge. When the work is done on a positive charge, electric potential also increases. The work done to assemble a number of charges from infinity to a particular point can be described as the electric potential by charges. The SI unit of potential difference is volt.