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Lorentz Force Calculator

Kaushik RabadiyaCreated by Kaushik RabadiyaLast updated: September 24, 2026

Lorentz force instantly calculates results using force, alpha, charge. Use the calculator above for instant answers in your browser.

The Lorentz Force Calculator is a powerful online tool designed for physics students, engineers, and educators to determine the magnetic force acting on a moving charged particle. By inputting the particle's charge, velocity, magnetic field strength, and the angle of trajectory, this calculator instantly solves for the resulting force vector magnitude. It eliminates manual computation errors and helps learners visualize the fundamental interaction between electromagnetism and moving matter.

How the Lorentz Force Formula Works

The calculation is based on the magnetic component of the Lorentz force law, which describes the force exerted on a charged particle moving through a magnetic field. The standard mathematical formula is expressed as:

F = q * v * B * sin(α)

Where F is the Lorentz force measured in Newtons (N), q represents the electric charge in Coulombs (C), v is the velocity of the particle in meters per second (m/s), B is the magnetic field strength in Teslas (T), and α is the angle between the velocity vector and the magnetic field vector. When the velocity and magnetic field are perpendicular (α = 90 degrees), the sine component equals 1, resulting in the maximum possible magnetic force.

Worked Calculation Example

Consider an experiment where an electron with a charge (q) of 1.6 x 10^-19 Coulombs travels at a high velocity (v) of 3.0 x 10^7 meters per second. It enters a uniform magnetic field (B) of 0.5 Teslas at an angle (α) of 30 degrees. To find the Lorentz force, we plug these values into our equation:

1. Identify the inputs: q = 1.6 x 10^-19 C, v = 3.0 x 10^7 m/s, B = 0.5 T, and α = 30 degrees.

2. Evaluate the sine term: sin(30°) = 0.5.

3. Multiply the values together: F = (1.6 x 10^-19) * (3.0 x 10^7) * (0.5) * (0.5).

4. Calculate the final result: F = 1.2 x 10^-12 Newtons. Thus, the magnetic force deflecting the electron is 1.2 x 10^-12 N.

Practical Tips for Physics Calculations

When working with electromagnetic equations, always ensure your units are converted to standard SI units before calculating—using Coulombs for charge, meters per second for velocity, and Teslas for magnetic fields. Pay close attention to the angle α; remember that if a charged particle moves parallel to the magnetic field lines (α = 0 or 180 degrees), the sine of the angle is zero, meaning no magnetic Lorentz force is exerted on the particle.

FAQs

How do I calculate the Lorentz force?

To calculate the magnetic component of the Lorentz force, multiply the electric charge of the particle by its velocity, the magnetic field strength, and the sine of the angle between the velocity and magnetic field vectors. Using a specialized calculator ensures precise handling of scientific notation and trigonometric functions.

How do I find the direction of the deflection due to the Lorentz force?

You can determine the direction of the deflection using the right-hand rule for positive charges. Point your right-hand fingers in the direction of the velocity vector, curl them toward the magnetic field vector, and your extended thumb will point in the direction of the resulting force. For negative charges, such as electrons, the force acts in the exact opposite direction.

What is the Lorentz force on an electron moving in a 0.5 T field at 0.1 c?

At 0.1 c (10% the speed of light), an electron's velocity is approximately 3.0 x 10^6 m/s. Assuming a perpendicular entry angle where sin(α) = 1, multiplying the electron charge (1.602 x 10^-19 C), velocity, and a 0.5 T magnetic field yields a Lorentz force of approximately 2.4 x 10^-13 Newtons.

Where can I find the Lorentz force in real-world applications?

The Lorentz force is foundational to many technologies we use daily. It operates inside particle accelerators like cyclotrons, governs the operation of electric motors and loudspeakers, and is responsible for deflecting charged particle beams inside cathode-ray tube displays and mass spectrometers.

Formula verified against NIST Reference Data — all calculations use deterministic, standards-based formulas.

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