Magnetism Formula and Sample Problems

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 μo (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 = μo (F/m) I(A) / 2 π d(m)

Where,

B →Strength of the magnetic field in (T. m2)

d →distance in (m)

I→ current in wire in (A)

μo→ permittivity of free space in (F/m)

F→ IlBsinΦ

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/s2.

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/s2.

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