What is an electric field strength?
2 Answers
Electric field strength, often referred to as **electric field intensity** or simply **electric field**, is a vector quantity that represents the force per unit charge experienced by a small positive test charge placed in the field. It describes how strong the electric field is at a specific point in space and the direction of the force acting on a positive charge.
Mathematically, the electric field strength **E** is defined as:
\[
\mathbf{E} = \frac{\mathbf{F}}{q}
\]
Where:
- **E** is the electric field strength (measured in newtons per coulomb, N/C, or volts per meter, V/m),
- **F** is the force experienced by the test charge (in newtons, N),
- **q** is the magnitude of the test charge (in coulombs, C).
The electric field strength at a point due to a point charge **Q** is given by Coulomb’s law:
\[
\mathbf{E} = \frac{k Q}{r^2}
\]
Where:
- **k** is Coulomb’s constant (approximately \( 8.99 \times 10^9 \, \text{N·m}^2/\text{C}^2 \)),
- **Q** is the charge creating the field,
- **r** is the distance from the charge to the point of interest.
The direction of the electric field is always away from positive charges and toward negative charges.
Mathematically, the electric field strength **E** is defined as:
\[
\mathbf{E} = \frac{\mathbf{F}}{q}
\]
Where:
- **E** is the electric field strength (measured in newtons per coulomb, N/C, or volts per meter, V/m),
- **F** is the force experienced by the test charge (in newtons, N),
- **q** is the magnitude of the test charge (in coulombs, C).
The electric field strength at a point due to a point charge **Q** is given by Coulomb’s law:
\[
\mathbf{E} = \frac{k Q}{r^2}
\]
Where:
- **k** is Coulomb’s constant (approximately \( 8.99 \times 10^9 \, \text{N·m}^2/\text{C}^2 \)),
- **Q** is the charge creating the field,
- **r** is the distance from the charge to the point of interest.
The direction of the electric field is always away from positive charges and toward negative charges.