Magnetic Force Calculator

Category: Physics
- April 04, 2025
| |

Calculate the magnetic force between two electrical currents or between a current and a moving charge. This calculator supports various configurations and provides step-by-step explanations.

Select Calculation Type

Wire Configuration

Advanced Options

About Magnetic Force

Magnetic forces arise from the interaction between moving charges or currents and magnetic fields. These forces are fundamental in electromagnetism and have numerous applications in technology.

Force Between Parallel Currents

When two current-carrying wires are placed parallel to each other, they exert a magnetic force on each other. This force is described by:

  • Force per unit length: F/L = (μ₀ × I₁ × I₂) / (2π × r)
  • Parallel currents in the same direction attract each other
  • Parallel currents in opposite directions repel each other
Lorentz Force on Moving Charges

A charged particle moving through a magnetic field experiences a force known as the Lorentz force:

  • Force: F = q × v × B × sin(θ)
  • The direction of the force is perpendicular to both the velocity and the magnetic field
  • The force is maximum when the velocity is perpendicular to the field (θ = 90°)
  • The force is zero when the velocity is parallel to the field (θ = 0° or 180°)
Magnetic Field of a Straight Wire

A straight current-carrying wire creates a magnetic field around it:

  • Field strength: B = (μ₀ × I) / (2π × r)
  • The field lines form concentric circles around the wire
  • The field strength decreases inversely with distance from the wire
Magnetic Field of a Solenoid

A solenoid is a coil of wire that creates a nearly uniform magnetic field inside it:

  • Field inside (ideal solenoid): B = μ₀ × n × I
  • Where n is the number of turns per unit length (N/L)
  • The field inside a long solenoid is nearly uniform and parallel to the axis
  • The field outside an ideal solenoid is approximately zero
Applications of Magnetic Forces

Magnetic forces have numerous practical applications:

  • Electric Motors: Convert electrical energy to mechanical energy
  • Generators: Convert mechanical energy to electrical energy
  • Electromagnets: Create controllable magnetic fields
  • Particle Accelerators: Use magnetic fields to guide charged particles
  • MRI Machines: Use strong magnetic fields for medical imaging
  • Magnetic Levitation: Used in maglev trains and other applications

What Is the Magnetic Force Calculator?

The Magnetic Force Calculator helps you determine the force that magnetic fields exert on moving charges, current-carrying wires, or between parallel wires. It’s a handy tool for students, educators, and professionals who need quick and reliable magnetic force calculations along with meaningful explanations.

Force on a Moving Charge:
\( F = q \cdot v \cdot B \cdot \sin(\theta) \)
Force on a Current-Carrying Wire:
\( F = I \cdot L \cdot B \cdot \sin(\theta) \)
Force Between Parallel Wires:
\( F = \frac{\mu_0 \cdot I_1 \cdot I_2 \cdot L}{2\pi r} \)

Key Features

  • Three calculation modes: Moving Charge, Current-Carrying Wire, Parallel Wires
  • Step-by-step explanations with clear visual diagrams
  • Unit conversion support for charge, velocity, current, magnetic field, and distance
  • Options to show force direction and scientific notation
  • Physical interpretation of results for better understanding

How to Use the Calculator

The calculator is interactive and user-friendly. Just follow these steps to get started:

  1. Select the type of calculation you need:
    • Force on Moving Charge – Use this when calculating the force on a particle like an electron in a magnetic field.
    • Force on Current-Carrying Wire – Perfect for estimating forces acting on conductors in magnetic fields.
    • Force Between Parallel Wires – Determine the attraction or repulsion between wires carrying current.
  2. Input the required values into the fields, such as charge, velocity, or current, and select the appropriate units.
  3. Set the angle between the direction of motion or current and the magnetic field.
  4. Adjust options for decimal places, scientific notation, and whether to show step-by-step details or vector directions.
  5. Click Calculate to see the results instantly.

Why This Calculator Is Useful

Understanding magnetic force is crucial in physics and engineering. This tool allows you to:

  • Quickly evaluate forces without manual calculations
  • Explore how different variables affect magnetic interactions
  • Visualise the direction and magnitude of magnetic forces
  • Support your learning with clear step-by-step explanations
  • Apply concepts to real-world applications like motors, sensors, and circuits

Frequently Asked Questions

What units does the calculator support?

You can input values in various units such as meters, centimetres, Tesla, Gauss, Amperes, microamperes, and even elementary charge units.

What does the angle (θ) represent?

It’s the angle between the direction of motion (or current) and the magnetic field. The force depends on the sine of this angle.

What is the “right-hand rule” mentioned in the output?

It’s a simple method to find the direction of the magnetic force. Point your thumb in the direction of motion or current, your fingers in the direction of the magnetic field, and your palm indicates the force direction.

Can I use this for negative charges?

Yes. The calculator takes into account the charge sign and adjusts the direction of the force accordingly.

What does “Force per Unit Length” mean?

In the parallel wires calculation, it indicates how much force acts on each metre of the wire, which is important for analysing distributed forces in long conductors.

Is this tool suitable for students?

Definitely. It’s designed to be clear and supportive, with diagrams, formulas, and interpretations that make learning more accessible.

Conclusion

The Magnetic Force Calculator simplifies your understanding of magnetic interactions. Whether you're studying physics, working on an electronics project, or just exploring magnetic phenomena, this tool helps you find answers faster and understand the results better.