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Magnetic Force Calculator

Calculate the force on a moving charge in a magnetic field.

Reviewed for accuracy by the Math Ora X team Last updated

Result

Understanding Magnetic Force Calculator

The Lorentz force on a moving charge in a magnetic field is perpendicular to both the velocity and the field direction (right-hand rule).

$$F = qvB\sin\theta$$

How to use this calculator

  1. Enter the charge value, \(q\), in coulombs.
  2. Enter the speed of the charge, \(v\), in meters per second.
  3. Enter the magnetic field strength, \(B\), in teslas.
  4. Enter the angle \(\theta\) between the velocity and the magnetic field, then calculate.

The formula explained

The formula \(F = qvB\sin\theta\) computes the magnetic force on a moving charge. It tells you how strong the force is based on the charge, its speed, the magnetic field, and the angle between the motion and the field.

  • F = magnetic force in newtons
  • q = charge in coulombs
  • v = speed of the charge in meters per second
  • B = magnetic field strength in teslas
  • \(\theta\) = angle between the velocity and the magnetic field

Step by step method

  1. Write down \(q\), \(v\), \(B\), and \(\theta\).
  2. Find \(\sin\theta\).
  3. Multiply \(q\), \(v\), \(B\), and \(\sin\theta\) to get \(F\).

Worked example

Problem. A charge of \(2\ \text{C}\) moves at \(3\ \text{m/s}\) through a magnetic field of \(4\ \text{T}\) at an angle of \(30^\circ\). Find the magnetic force.

  1. Use \(F = qvB\sin\theta\).
  2. Substitute the values: \(F = 2 \times 3 \times 4 \times \sin 30^\circ\). Since \(\sin 30^\circ = \frac{1}{2}\), this becomes \(F = 2 \times 3 \times 4 \times \frac{1}{2}\).
  3. Compute the result: \(F = 12\ \text{N}\).

Answer. \(12\ \text{N}\)

Tips and common mistakes

  • If the angle is \(0^\circ\), the force is \(0\) because \(\sin 0^\circ = 0\).
  • Make sure the angle is the one between the direction of motion and the magnetic field, not just any angle in the problem.

Frequently asked questions

How do I use the magnetic force calculator?+

Enter the charge, speed, magnetic field strength, and the angle between the velocity and the magnetic field. The calculator uses F = qvBsinθ to find the magnetic force on the moving charge.

What does the formula F = qvBsinθ mean?+

It means the force depends on charge size, how fast it moves, the magnetic field strength, and the angle between the motion and the field. The sine term shows that the force is largest when the motion is perpendicular to the field and zero when they are parallel.

What units should I use for the inputs?+

Use coulombs for charge, meters per second for speed, teslas for magnetic field strength, and degrees or radians for the angle, depending on the calculator’s angle setting. The force is then reported in newtons.

What happens if the angle is 0 degrees or 90 degrees?+

At 0 degrees, sinθ = 0, so the magnetic force is zero because the charge moves along the field. At 90 degrees, sinθ = 1, so the force is at its maximum for the given values.

How is magnetic force different from electric force?+

Magnetic force acts on moving charges and depends on their velocity and direction relative to the magnetic field. Electric force can act on charges even when they are at rest, because it depends on electric fields rather than motion.

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