Question

A voltmeter measures:
A. Electric potential energy
B. Electrical potential gradient
C. Electric potential difference
D. Electric field

Answer 1

A device which is always connected in parallel to a given number of elements, to measure the voltage drop in the elements.

Complete step by step answer: In this question, we are given a voltmeter, which we already know is a measuring instrument.
We are asked to find out where it is used, we mean which one of the physical quantities it is used to measure.

To begin with, let us first go through each of the following options.

Electric potential energy, or Electrostatic potential energy, is a potential energy (measured in joules) derived from the conservative Coulomb forces and correlated with the arrangement within a given structure of a certain set of point charges. By means of two main components, an object may have electrical potential energy: its own electrical charge and its relative location to other electrically charged objects.

A potential gradient is the local rate of change of the potential with respect to displacement, i.e. spatial derivative, or gradient, in physics, chemistry and biology. This quantity also exists in physical process calculations because it contributes to some sort of flux.

The difference in electrical potential between two points is voltage, electrical potential difference, electrical pressure or electrical stress, which (in a static electrical field) is defined as the work required per unit of charge to transfer a test charge between the two points. The derived unit for voltage (potential difference) is called volt in the International System of Units.

The actual field surrounding each electric charge and exerting force on all other charges in the field, either attracting or repelling them, is an electric field (sometimes an E-field). Electric fields arise from electric charges, or from magnetic fields which differ in time. Both electric and magnetic fields are embodiments of the electromagnetic force, one of the four basic forces (or interactions) of existence.

A voltmeter is a device that is used in an electrical circuit to calculate the electrical potential difference between two points. In proportion to the voltage of the circuit, analogue voltmeters pass a pointer over a scale; digital voltmeters provide a numerical voltage display using an analogue to digital converter.

From the above explanation it is clear that voltmeter is used to measure electric potential difference of a circuit. The correct option is C.

Note: Voltmeter is a device which is always connected in parallel to the elements of whose potential difference is to be measured. Voltameter has a very high value of resistance. If it is connected in series, then the current I the circuit will almost be nil, due to its high resistance.