Question

The energy which an electron acquires when accelerated, through a potential difference of 1 volt is called as
A. 1 Joule
B. 1 eV
C. 1 erg
D. 1 Watt

Answer 1

Hint:Before going to solve this question we need to understand the potential energy. Potential difference is defined as the difference in the amount of energy that the charge carriers have between two points in a circuit. Or it can also be defined as the amount of work done in moving a unit charge from one point to another. Usually, the potential difference is measured in volts.

Formula used:
The expression of energy of a electron is given by,
\[E = qV\]
Here, q is the charge of an electron and V is the potential difference.

Complete step by step solution:
We know that the energy of an electron is given by,
\[E = qV\]
Here, q is the charge of an electron, that is we know that \[q = 1e\].
Therefore,
\[ \Rightarrow E = 1eV\]
1ev is defined as the energy that is gained by an electron when it has been accelerated by a potential difference of 1 volt.

If we calculate the energy in terms of joules then,
\[E = 1.6 \times {10^{ - 19}}C \times 1V\]
\[ \Rightarrow E = 1.6 \times {10^{ - 19}}J\]
If we calculate the energy in terms of erg then,
\[1J = {10^{ - 7}}\,ergs\]
Then,
\[ \therefore E = 1.6 \times {10^{ - 12}}\,ergs\]
Therefore, the energy that an electron will acquire when it is accelerated through a potential difference of 1 volt is called 1eV.

Hence, option B is the correct answer.

Note:Suppose when a charged particle is placed inside an electric field (an electron), it exerts a force on the charged particle in which the force is equal to qE. Due to this force, the charged particle (an electron) starts accelerating. The direction of the force on the electron (and also the acceleration) is opposite the direction of the electric field, since the electron has a negative charge.