The SI unit for field strength depends on the type of field you're referring to. Here are the SI units for different field strengths:
1. **Electric Field Strength**: The SI unit is the **volt per meter (V/m)**. It measures the force exerted per unit charge at a point in the field.
2. **Magnetic Field Strength (also known as Magnetic Field Intensity)**: The SI unit is the **ampere per meter (A/m)**. It describes the strength of the magnetic field produced by a current or magnetic material.
3. **Magnetic Flux Density (often just called "magnetic field")**: The SI unit is the **tesla (T)**. This is different from magnetic field strength and measures the density of the magnetic flux passing through a unit area.
4. **Gravitational Field Strength**: The SI unit is the **newton per kilogram (N/kg)**. This represents the force per unit mass experienced in a gravitational field.
Each type of field strength is crucial in its respective domain, such as electromagnetism, magnetism, and gravitation.