Which of the following would decrease the magnetic field around a wire?
1 answer:
The correct answer is
<span>A. decreasing the current
In fact, the magnetic field produced by a current carrying wire is given by
</span>
<span>where
</span>
is the vacuum permeability
<span>I is the current in the wire
r is the distance from the wire at which the field is calculated
We see from the formula that the intensity of the field, B, is directly proportional to the current I, so if the current decreases, the magnetic field strength B decreases as well.</span>
<span>A. decreasing the current
In fact, the magnetic field produced by a current carrying wire is given by
</span>
<span>where
</span>
<span>I is the current in the wire
r is the distance from the wire at which the field is calculated
We see from the formula that the intensity of the field, B, is directly proportional to the current I, so if the current decreases, the magnetic field strength B decreases as well.</span>
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Answer:
The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field.
The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current.
The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines.
Explanation:
The magnitude of the magnetic force exerted on a current-carrying wire due to a magnetic field is given by
(1)
where I is the current, L the length of the wire, B the strength of the magnetic field, the angle between the direction of the field and the direction of the current.
Also, B, I and F in the formula are all perpendicular to each other. (2)
According to eq.(1), we see that the statement:
<em>"The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines.</em>"
is correct, because when the current is perpendicular to the magnetic field, and the force is maximum.
Moreover, according to (2), we also see that the statements
<em>"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field. "</em>
<em>"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current. "</em>
because F (the force) is perpendicular to both the magnetic field and the current.