## Magnetism Formula :

Strength of the magnetic field B _{(T.m)2} in tesla meter square is equal to the product of the permittivity of free space μ_{o (F/m)} farad per meter is multiply by current in wire I_{(A)} in Ampere is divided by distance d_{(m)} in meter. Hence magnetism formula has been written as,

**B _{(T.m)2} = μ_{o (F/m) }I_{(A)} / 2 π d_{(m)}**

Where,

B →Strength of the magnetic field in (T. m^{2})

d →distance in (m)

I→ current in wire in (A)

μ_{o}→ permittivity of free space in (F/m)

F→ IlB_{sinΦ}

## Sample Problems :

### Example 1:

The strength of a uniform magnetic field through a 2 m long wire with 7 A current is 3.5 T. Find the force on the wire if it makes an angle of 30 degrees.

### Solution :

We know, F = ILBsinθ

Here, I = 7 A,

L = 2 m,

B = 3.5 T,

θ = 30°

F = (7 A)(2 m)(3.5 T)(sin30°)

F = 24.5 kg m/s^{2}.

### Example 2:

The strength of a uniform magnetic field through a 0.5 m long wire with 3 A current is 8 T. Find the force on the wire if it makes an angle of 30 degrees.

### Solution :

We know, F = ILBsinθ

Here, I = 4 A,

L = 0.5 m,

B = 8 T,

θ = 30°

F = (4 A)(0.5 m)(8 T)(sin30°)

F = 8 kg m/s^{2}.