Cyclotron Frequency

f = q · B / (2π · m)

Quick answer

This calculator solves f = q × B / (2π × m) for Frequency. With Charge 100 mC, Flux Density 0.5 T, Particle Mass 1 kg, the result is 0.007958 Hz. It solves in 4 directions, so you can enter the values you have and get the one you need.

Calculator

Frequency (Hz)
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Formula

f = q × B / (2π × m)

Description

A charged particle moving in a magnetic field circles at the cyclotron frequency, which depends only on the charge-to-mass ratio and the field strength—not on the particle’s speed or orbit radius. This frequency-independence of energy is what makes cyclotron particle accelerators and electron-cyclotron-resonance sources work, and it sets the resonance used in mass spectrometry.

Variables

  • f — Cyclotron frequency (Hz)
  • q — Particle charge (C)
  • B — Magnetic flux density (T)
  • m — Particle mass (kg)

Practical Notes

For an electron (q/m ≈ 1.76×10¹¹ C/kg), the cyclotron frequency is about 28 GHz per tesla. The orbit radius r = m·v/(q·B) grows with speed even though the frequency stays fixed.

Symbols and units

Symbol Meaning Default unit Accepted units
f Frequency Hz Hz, kHz, MHz, GHz
q Charge C pC, nC, µC, mC, C
B Flux Density T G, mT, T
m Particle Mass kg kg, g, mg

Step by step

  1. 1. What you know: Charge 100 mC, Flux Density 0.5 T, Particle Mass 1 kg
  2. 2. The relation: f = q × B / (2π × m)
  3. 3. Substitute: q = 100 mC, B = 0.5 T, m = 1 kg
  4. 4. Result: Frequency = 0.007958 Hz

Worked examples

Minimum range

Given: Charge 100 µC, Flux Density 10 G, Particle Mass 1 g

Result: Frequency = 1.59 × 10⁻⁵ Hz

Low range

Given: Charge 1 mC, Flux Density 10 mT, Particle Mass 10 g

Result: Frequency = 1.59 × 10⁻⁴ Hz

Typical

Given: Charge 100 mC, Flux Density 0.5 T, Particle Mass 1 kg

Result: Frequency = 0.007958 Hz

High range

Given: Charge 1 C, Flux Density 1.5 T, Particle Mass 100 kg

Result: Frequency = 0.002387 Hz

Maximum range

Given: Charge 10 C, Flux Density 15 T, Particle Mass 1000 kg

Result: Frequency = 0.02387 Hz

Solving for each variable

Solve for Frequency

Charge 100 µC, Flux Density 10 G, Particle Mass 1 g → 1.59 × 10⁻⁵ Hz

Solve for Charge

Frequency 5 Hz, Flux Density 10 G, Particle Mass 1 g → 31.42 C

Solve for Flux Density

Frequency 5 Hz, Charge 100 µC, Particle Mass 1 g → 314.2 T

Solve for Particle Mass

Frequency 5 Hz, Charge 100 µC, Flux Density 10 G → 0.003183 mg

How Frequency changes with Charge

Charge (input) Frequency (result)
10 mC 7.96 × 10⁻⁴ Hz
25 mC 0.001989 Hz
50 mC 0.003979 Hz
75 mC 0.005968 Hz
100 mC 0.007958 Hz
150 mC 0.01194 Hz
0.2 C 0.01592 Hz
0.4 C 0.03183 Hz
0.7 C 0.0557 Hz
1 C 0.07958 Hz

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Frequently asked questions

How do you calculate Cyclotron Frequency?

Use f = q × B / (2π × m). With Charge 100 mC, Flux Density 0.5 T, Particle Mass 1 kg, Frequency works out to 0.007958 Hz.

What is the formula for Cyclotron Frequency?

The formula is f = q × B / (2π × m). A charged particle moving in a magnetic field circles at the cyclotron frequency, which depends only on the charge-to-mass ratio and the field strength—not on the particle’s speed or orbit radius.

How do you find Charge when you know the other values?

Rearrange for Charge: with Frequency 5 Hz, Flux Density 10 G, Particle Mass 1 g, Charge is 31.42 C.

How do you find Flux Density when you know the other values?

Rearrange for Flux Density: with Frequency 5 Hz, Charge 100 µC, Particle Mass 1 g, Flux Density is 314.2 T.