Understanding the Electric Field Definition

The question asks for the fundamental definition of an Electric Field. An electric field is a vector field that describes the electric force exerted on a positive test charge placed at any point in space surrounding an electric charge or a distribution of charges.

Defining the Electric Field

In physics, the electric field ($\vec{E}$) at a point is precisely defined as the electric force ($\vec{F}$) acting on a small positive test charge ($q_0$) placed at that point, divided by the magnitude of the test charge. Mathematically, this is expressed as:

$$ \vec{E} = \frac{\vec{F}}{q_0} $$

The unit of the electric field in the International System of Units (SI) is Newtons per Coulomb (N/C).

Analysis of Options

Let's examine each option provided:

• Option 1: Potential per unit charge

  This describes electric potential difference (voltage) in relation to work done, or relates potential to the electric field via $\vec{E} = -\nabla V$. However, it is not the direct definition of the electric field itself.

• Option 2: Force Per Unit Charge

  This option directly matches the established definition of the electric field, $\vec{E} = \frac{\vec{F}}{q_0}$. The electric field strength at a point is the force experienced by a unit positive charge placed there.

• Option 3: Voltage per unit Current

  According to Ohm's Law, Voltage ($V$) divided by Current ($I$) gives Resistance ($R$), where $R = \frac{V}{I}$. This concept belongs to circuit analysis and is unrelated to the definition of the electric field.

• Option 4: None of These

  Since Option 2 accurately defines the electric field, this option is incorrect.

Conclusion

Based on the standard definition in physics and electrostatics, the electric field is correctly defined as the force per unit charge.