Magnetic Field and Forces Equations

Physical Quantities

Quantity

Symbol

Scalar/Vector

Units

Magnetic field

B\mathbf{B}

Vector

Tesla (T)

Current

II

Scalar

Ampere (A)

Permeability of free space

μ0\mu_0

Scalar

T/A

Distance from the wire

rr

Scalar

Meter (m)

Current loop radius

RR

Scalar

Meter (m)

Length

\ell

Scalar

Meter (m)

Angle

θ\theta

Scalar

Radians (rad)

Force

F\mathbf{F}

Vector

Newton (N)

Charge

qq

Scalar

Coulomb (C)

Number of turns in the coil

NN

Scalar

None

Speed

vv

Scalar

Meter per second (m/s)

Potential Difference

VV

Scalar

Volt (V)

Mass

mm

Scalar

Kilogram (kg)

Torque magnitude

τ\tau

Scalar

Newton-meter (N\m)

Angle between field and coil

ϕ\phi

Scalar

Radians (rad)

Magnetic moment

MM

Vector

Ampere-square meter (A/m²)

/

Equations Summary

Equation

Formula

Magnetic field of straight wire

B=μ0I2πrB = \frac{\mu_0 I}{2 \pi r}

Magnetic field of a wire loop

B=μ0I2RB = \frac{\mu_0 I}{2 R}

Magnetic force on a current carrying wire

F=IBsin(θ)F = I \ell B \sin(\theta)

Force between two wires carrying current

F

Force on a moving charge

F=qvBsin(θ)F = q v B \sin(\theta)

Path radius of a charge moving in magnetic field

r = \frac{m v}{\left

Particle mass in a mass spectrometer

m = \frac{\left