Question

What is the derived unit of electric field intensity?

Answer 1

The electric field intensity, often referred to simply as the electric field, is a vector quantity that describes the force per unit charge experienced by a test charge placed in the field. The derived unit for electric field intensity in the International System of Units (SI) is the volt per meter (V/m).

Here’s how we arrive at this unit:

1. **Definition of Electric Field Intensity (E)**:
   \[ E = \frac{F}{q} \]
   where \( F \) is the force experienced by a test charge, and \( q \) is the magnitude of the test charge.

2. **Units of Force**:
   In SI units, the force \( F \) is measured in newtons (N).

3. **Units of Charge**:
   The charge \( q \) is measured in coulombs (C).

4. **Combining the Units**:
   Thus, the unit of electric field intensity can be expressed as:
   \[ \text{Unit of } E = \frac{\text{Unit of } F}{\text{Unit of } q} = \frac{\text{N}}{\text{C}} \]

5. **Volt per Meter (V/m) Conversion**:
   A volt (V) is defined as one joule per coulomb (J/C), and a joule (J) is one newton meter (N·m). So, we can convert:
   \[ 1 \text{ V} = \frac{1 \text{ J}}{1 \text{ C}} = \frac{1 \text{ N·m}}{1 \text{ C}} \]
   Therefore:
   \[ 1 \text{ V/m} = \frac{1 \text{ N·m}}{1 \text{ C·m}} = \frac{1 \text{ N}}{1 \text{ C}} \]

So, the unit of electric field intensity, volt per meter (V/m), is equivalent to newtons per coulomb (N/C).

Answer 2

The derived unit of electric field intensity is volts per meter (V/m). This is obtained from the formula for electric field intensity, which is the force per unit charge (N/C) or the potential difference per unit distance.