1. The following factors influence the magnetic induction on the conductor wire.

(1) the current flowing in the wire

(2) permittivity

(3) wire density

(4) the distance of a point from the wire

Which statements are correct

Solution :

The equation of magnetic induction of a wire :

μ_{o }= Permeability of a vacuum or magnetic constant

I = Electric current flowing on the wire

r = the distance of a point from the wire

B = the magnitude of magnetic induction

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2. Note the statements related to the following magnetic induction.

(1) the current flowing in the wire

(2) the permeability of a vacuum

(3) wire cross-sectional area

(4) wire density

What affects magnetic induction magnitudes on a wire conductor.

Solution

Learn the magnetic induction formula and previous description.

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3. The electric current I flows on the conductor wire. What is the magnetic induction at the center of the circle (P)? (µ_{o} = 4π.10^{-7} Wb.m^{-1}.A^{-1})

__Known :__

Radius of circle (r) = 6 cm = 6 x 10^{-2} meters

Electric current (I) = 8 Ampere

Permeability of a vacuum (µ_{o}) = 4π x 10^{-7 }Wb.A^{-1} m^{-1}

__Wanted:__ the magnetic induction at the center of the circle (P)

__Solution :__

360^{o} – 90^{o} = 270^{o}. 270^{o} / 360^{o} = 3/4 then 270^{o} = 3/4 circumference

The magnetic field formula at the center of the coil with a number of loops:

*B = magnetic field, N = number of windings, I = electric current, r = radius of curvature*

In the above problem, there is only one winding so that N is removed from the equation. The wire coil on the above problem is not 1 circle but 3/4 circle. The above formula is adjusted again with this problem :

The magnetic induction at the center of the circle :

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4. Current 2 A flows on a circular wire like the picture. What is the magnitude and direction of magnetic induction at point P if the radius of circle 4π cm.

__Known :__

Radius (r) = 4π cm = 4π x 10^{-2} meters

Electric current (I) = 2 Ampere

Permeability of a vacuum (µ_{o}) = 4π x 10^{-7 }Wb.A^{-1} m^{-1}

__Wanted :__ The magnitude and direction of magnetic induction at point P

__Solution :__

The wire coil on the above problem is 1/2 circle.

The magnitude of magnetic induction at point P :

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