# Magnetic Flux Formula

## Magnetic Flux Formula

Magnetic flux is defined as the total number of magnetic field lines through a given coil or area. It is the normal component of magnetic field which passes through the area. Magnetic flux is denoted by ΦB where B represents magnetic field, and its unit is measured in Weber (Wb). The value of magnetic flux is a vector quantity and it depends on the direction of the magnetic field.

The magnetic flux formula is given by,

$\Phi_{B}\,&space;=\,&space;B.A$

$\Phi_{B}\,&space;=\,&space;BACos\theta$

Where,

B = magnetic field,

A = surface area and

Θ = angle between the normal to the surface and magnetic field.

Example 1

The Dimension of a rectangular loop is 0.50m and 0.60m. B and θ are 0.02T and 45° respectively. Determine the magnetic flux through the surface.

Solution:

Given parameters are,

Dimensions of rectangular loop = 0.50m and 0.60m,

B = 0.02T,

θ = 45°

Magnetic flux formula is given by

ΦB = B A Cosθ

Area, A = 0.50 × 0.60

= 0.3 m2

ΦB = 0.02 × 0.3 × Cos 45

= 0.00312 Wb

Example 2

The dimension of floor of a house is 20m by 15m. Vertical component of the magnetic field is 4.5 × 10-5T, determine the magnetic flux.

Solution:

Given parameters are,

Dimensions of house = 20m by 15m,

B = 4.5×10-5T,

Because it is a vertical component, θ = 0°

Magnetic flux formula is given by,

ΦB = B A Cosθ

Area, A = 20 ×15

= 300 m2

ΦB = 4.5 × 10-5 × 300 × Cos 0

=  1350 x 10-5 Wb

#### Practise This Question

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