Magnetic Field with three parallel wires

In summary, the question asks which wire experiences the greatest net force due to two other equally spaced wires carrying currents with opposite directions. The equation for calculating the force is FAB = μ°I1 I2 / 2∏d. The correct answer is wire B, as it experiences a net force of 2I^2/d due to the attractive forces between the positively charged wires A and B and the repulsive force between wire C, which is negatively charged.
  • #1
rikinmathur
1
0

Homework Statement


Three long, straight wires are carrying currents that have
the same magnitude. In C the current is opposite to that
in A and B. The wires are equally spaced. Each wire experiences a net force due to the other two wires. Which
wire experiences a net force that has the greatest magnitude?

A =====>====
B=====>====
C=====<====

Homework Equations


FAB = μ°I1 I2 / 2∏d

The Attempt at a Solution


It says that the answer is B because 2I squared / d is the net force on B. But the way I am doing it is -I^2/d + I^2/d = 0, hence the net forces cancel out and the force on B is zero. I don't understand how it is 2I^2/d. Please help.
 
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  • #2
Hi rikinmathur! Welcome to pf! :smile:

What are the direction of forces on wire B due to the other two wires?
 
  • #3
Hey rikinmathur, just think in terms of charges, maybe this is easier for you: A and B are positively charged (in a magnetic sense) and C is negative. So, which wire-pairs will experience an attractive and which a repulsive force?
 

1. What is a magnetic field?

A magnetic field is an invisible force that is created by moving electric charges or currents. It is a vector field, meaning it has both magnitude and direction.

2. How does a magnetic field interact with three parallel wires?

When three parallel wires are placed close to each other, the magnetic fields created by each wire will interact with each other. This can result in attraction or repulsion between the wires depending on the direction of the currents.

3. What is the right-hand rule for determining the direction of the magnetic field?

The right-hand rule is a method for determining the direction of a magnetic field. Point your right thumb in the direction of the current, and your fingers will curl in the direction of the magnetic field.

4. How is the strength of the magnetic field affected by the distance between the wires?

The strength of the magnetic field is inversely proportional to the distance between the wires. This means that as the distance increases, the strength of the magnetic field decreases.

5. Can the magnetic field of three parallel wires be used for practical purposes?

Yes, the magnetic field created by three parallel wires can be used for various practical purposes. For example, it can be used in motors, generators, and magnetic levitation systems.

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