Magnetic Field Calculator
Calculate magnetic field strength, magnetic force, and magnetic flux with interactive visualization
Parameters
Calculated Values
Examples
Example 1: Household Current
A 10A household current at 10cm distance.
- Magnetic Field:
- Magnetic Force:
- Magnetic Flux:
Example 2: High Current Wire
A 100A industrial current at 1m distance.
- Magnetic Field:
- Magnetic Force:
- Magnetic Flux:
Example 3: Electron in Field
An electron moving at high velocity.
- Magnetic Field:
- Magnetic Force:
- Magnetic Flux:
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
Step-by-Step Solution
See how the main results are calculated.
Step 1: Identify Known Values
List the given values from the problem:
Equation:
Calculation:
Explanation:
We start by identifying what values we know and what we need to find.
Step 2: Calculate Magnetic Field
Use Ampere's Law to find magnetic field strength:
Equation:
Calculation:
Explanation:
Magnetic field strength is calculated using Ampere's Law for a long straight wire.
Step 3: Calculate Magnetic Force
Use the Lorentz force formula to find magnetic force:
Equation:
Calculation:
Explanation:
Magnetic force on a moving charged particle is calculated using the Lorentz force formula.
Step 4: Calculate Magnetic Flux
Use the magnetic flux formula:
Equation:
Calculation:
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
- If the distance from a current-carrying wire is doubled, the magnetic field strength becomes:
- What is the magnetic field strength 1m from a 10A current?
- The magnetic force on a charged particle is maximum when:
- Which of the following is NOT a unit of magnetic field?
- The direction of magnetic field around a current-carrying wire is: