Magnetic Field Calculator

Calculate magnetic field strength, magnetic force, and magnetic flux with interactive visualization

Parameters

Aⓘ
Current in the wire (positive or negative)
mⓘ
Distance from the wire
mⓘ
Length for flux calculation
Cⓘ
Charge of moving particle
m/sⓘ
Velocity of charged particle
Magnetic Field Analysis
Enter values to calculate magnetic field, force, and flux

Calculated Values

Magnetic Field:
0.000010;T0.000010;T
Magnetic Force:
0.000000;N0.000000;N
Magnetic Flux:
0.000001;Wb0.000001;Wb
Field at 1m:
0.000001;T0.000001;T

Examples

Example 1: Household Current

A 10A household current at 10cm distance.

  • Magnetic Field: 0.000020.00002
  • Magnetic Force: 2e−82e-8
  • Magnetic Flux: 0.0000010.000001

Example 2: High Current Wire

A 100A industrial current at 1m distance.

  • Magnetic Field: 0.000020.00002
  • Magnetic Force: 2e−82e-8
  • Magnetic Flux: 0.0000020.000002

Example 3: Electron in Field

An electron moving at high velocity.

  • Magnetic Field: 0.000020.00002
  • Magnetic Force: 3.2e−183.2e-18
  • Magnetic Flux: 2e−72e-7

Magnetic Fields and Forces

A magnetic field is a region of space around a magnet or current-carrying conductor where magnetic forces can be detected. The magnetic field strength at any point is defined as the force per unit charge that would be experienced by a moving charged particle at that point.

For a long straight current-carrying wire, the magnetic field strength is given by B = μ₀I/(2πr), where μ₀ is the permeability of free space (4π × 10⁻⁷ T⋅m/A), I is the current, and r is the distance from the wire. The field forms concentric circles around the wire.

The magnetic force on a moving charged particle is given by F = qvB sin(θ), where q is the charge, v is the velocity, B is the magnetic field strength, and θ is the angle between the velocity and magnetic field vectors. This is known as the Lorentz force.

Magnetic flux is the total magnetic field passing through a surface. It is calculated as Φ = B⋅A⋅cos(θ), where B is the magnetic field strength, A is the area, and θ is the angle between the field and the normal to the surface.

The direction of the magnetic field around a current-carrying wire can be determined using the right-hand rule: if you point your thumb in the direction of the current, your fingers curl in the direction of the magnetic field lines.

Key Concepts

  • Magnetic Field: B = μ₀I/(2πr) (field around current-carrying wire)
  • Magnetic Force: F = qvB sin(θ) (Lorentz force)
  • Magnetic Flux: Φ = B⋅A⋅cos(θ) (total field through surface)
  • Permeability: μ₀ = 4π × 10⁻⁷ T⋅m/A (free space)
  • Right-Hand Rule: Thumb = current, fingers = field direction
  • Field Direction: Concentric circles around wire

Real-World Applications

  • Electric Motors: Understanding magnetic forces on current-carrying wires
  • Particle Accelerators: Controlling charged particle motion
  • Magnetic Resonance Imaging (MRI): Using strong magnetic fields
  • Electric Generators: Converting mechanical to electrical energy
  • Magnetic Levitation: Using magnetic fields for suspension

Physics Equations

Magnetic Field (Ampere's Law):
B=μ0I2πrB = \frac{\mu_0 I}{2\pi r}
Magnetic Force (Lorentz Force):
F=qvBsin⁡(θ)F = qvB\sin(\theta)
Magnetic Flux:
Φ=BAcos⁡(θ)\Phi = BA\cos(\theta)
Permeability of Free Space:
μ0=4π×10−7 T⋅m/A\mu_0 = 4\pi \times 10^{-7} \text{ T⋅m/A}
Right-Hand Rule:
Thumb=I,Fingers=B\text{Thumb} = I, \text{Fingers} = B

Step-by-Step Solution

See how the main results are calculated.

1

Step 1: Identify Known Values

List the given values from the problem:

Equation:

\text{Given: } I = ${I} \text{ A}, r = ${r} \text{ m}, q = ${q} \text{ C}, v = ${v} \text{ m/s}

Calculation:

I=5 Ar=0.1 mq=0.000001 Cv=1000 m/sI = 5 \text{ A} \\ r = 0.1 \text{ m} \\ q = 0.000001 \text{ C} \\ v = 1000 \text{ m/s}

Explanation:

We start by identifying what values we know and what we need to find.

2

Step 2: Calculate Magnetic Field

Use Ampere's Law to find magnetic field strength:

Equation:

B=μ0I2πrB = \frac{\mu_0 I}{2\pi r}

Calculation:

B=0.0000012566370614359173×52π×0.1=0.000010 TB = \frac{0.0000012566370614359173 \times 5}{2\pi \times 0.1} = 0.000010 \text{ T}

Explanation:

Magnetic field strength is calculated using Ampere's Law for a long straight wire.

3

Step 3: Calculate Magnetic Force

Use the Lorentz force formula to find magnetic force:

Equation:

F=qvBsin⁡(θ)F = qvB\sin(\theta)

Calculation:

F=0.000001×1000×0.000010×sin⁡(90°)=0.000000010000 NF = 0.000001 \times 1000 \times 0.000010 \times \sin(90°) = 0.000000010000 \text{ N}

Explanation:

Magnetic force on a moving charged particle is calculated using the Lorentz force formula.

4

Step 4: Calculate Magnetic Flux

Use the magnetic flux formula:

Equation:

Φ=BAcos⁡(θ)\Phi = BA\cos(\theta)

Calculation:

Φ=0.000010×0.5×0.1×cos⁡(0°)=0.00000050 Wb\Phi = 0.000010 \times 0.5 \times 0.1 \times \cos(0°) = 0.00000050 \text{ Wb}

Explanation:

Magnetic flux is the total magnetic field passing through a surface area.

Frequently Asked Questions (FAQ)

What is a magnetic field?

A magnetic field is a region of space around a magnet or current-carrying conductor where magnetic forces can be detected. It represents the force per unit charge that would be experienced by a moving charged particle.

How do I calculate magnetic field strength?

For a long straight wire, use B = μ₀I/(2πr), where μ₀ is the permeability of free space, I is the current, and r is the distance from the wire.

What is the Lorentz force?

The Lorentz force is the magnetic force on a moving charged particle, given by F = qvB sin(θ), where q is charge, v is velocity, B is magnetic field, and θ is the angle between velocity and field.

How does distance affect magnetic field strength?

Magnetic field strength decreases with distance from the current-carrying wire. It follows a 1/r relationship, so doubling the distance halves the field strength.

What is magnetic flux?

Magnetic flux is the total magnetic field passing through a surface, calculated as Φ = B⋅A⋅cos(θ), where B is field strength, A is area, and θ is the angle.

How do I determine magnetic field direction?

Use the right-hand rule: point your thumb in the direction of the current, and your fingers curl in the direction of the magnetic field lines around the wire.

Practice MCQs

  1. If the distance from a current-carrying wire is doubled, the magnetic field strength becomes:
  2. What is the magnetic field strength 1m from a 10A current?
  3. The magnetic force on a charged particle is maximum when:
  4. Which of the following is NOT a unit of magnetic field?
  5. The direction of magnetic field around a current-carrying wire is: