Question

# Potential difference is measured by.A. AmmeterB. VoltmeterC. LactometerD. Dry cell

Hint: Define potential and the potential difference. In any circuit we measure the potential difference between two points. The unit of potential difference is Volt. Find out what the instruments given in the questions do.

Potential can be defined as the amount of work done needed to transfer a charge from a reference point to another specific point inside the field.

Potential difference between two points can be defined as the amount of work done needed to transfer a unit charge from one point to the other point. The potential difference can also be defined as the difference in the electric potential of the two charge bodies on the two points.
The unit of electric potential or potential difference is volt.

Mathematically we can define the electric potential as the amount of work done per unit charge.

So, we can write, potential $V=\dfrac{W}{Q}$
Where, V is the potential, W is the work done and Q is the charge.

If the potential at one point is ${{V}_{1}}$ and the potential at another point is ${{V}_{2}}$ , the potential difference between these two points can be given as,

$V={{V}_{1}}-{{V}_{2}}$

The potential difference between two points is measured by voltmeter. It is connected in parallel to the conductor to find the potential difference between the connected points.

So, the correct answer is “Option B”.

Note:
Ammeter is an instrument which can measure the amount of current flowing through a conductor. Lactometer is used to measure the amount of water mixed in milk. Dry cell is an electrochemical cell which stores chemical energy and this chemical energy can be converted into electrical energy.