Force of attraction. When one current is reversed, the force acting between two parallel wires carrying currents becomes repulsive.

When the current goes the same way in the two wires, the force is attractive. When the currents go opposite ways, the force is repulsive. You should be able to confirm this by looking at the magnetic field set up by one current at the location of the other wire, and by applying the right-hand rule.

Will a pair of parallel current-carrying wires exert forces on each other? 1. yes; the wires are electrically charged.

Once you have calculated the force on wire 2, of course the force on wire 1 must be exactly the same magnitude and in the opposite direction according to Newton’s third law. radial separation between wires r = m, the magnetic field at wire 2 is B = Tesla = Gauss. The earth’s magnetic field is about 0.5 gauss.

Section Summary

1. The force between two parallel currents I1 and I2, separated by a distance r, has a magnitude per unit length given by. Fl=μ0I1I22πr F l = μ 0 I 1 I 2 2 π r .
2. The force is attractive if the currents are in the same direction, repulsive if they are in opposite directions.

Magnetic field is a vector quantity and we cannot just add them based on only magnitudes. They also have directions so when two vectors are added, the resultant depends on the magnitudes of both vectors & angle between those vectors.

The sum of a and b is a+b. This is not true for magnetic fields because magnetic fields are vectors – they have direction as well as size. The sum of a and b is only a+b if the two vectors are exactly in line. Usually they are not in line and the resultant is less than a+b.

Reason – The two magnetic field lines do not intersect each other because if they do, it means at the point of intersecting, the compass needle is showing two different directions, which are not possible.

Magnetic field lines can never cross, meaning that the field is unique at any point in space. Magnetic field lines are continuous, forming closed loops without beginning or end. They go from the north pole to the south pole.

A: It’s not really true that magnetic field lines cannot cross, but where they do, the magnetic field strength has to be zero. Here’s why: A magnetic field line is that path in space that points in the direction of the magnetic field at every point along it.

Every single location in space has its own electric field strength and direction associated with it. Consequently, the lines representing the field cannot cross each other at any given location in space.

Equipotential lines at different potentials can never cross either. This is because they are, by definition, a line of constant potential. The equipotential at a given point in space can only have a single value. Note: It is possible for two lines representing the same potential to cross.

Electric lines of force never intersect each other because, at the point of intersection, two tangents can be drawn to the two lines of force. This means two directions of the electric field at the point of intersection, which is not possible.

The relative magnitude of the electric field is proportional to the density of the field lines. Where the field lines are close together the field is strongest; where the field lines are far apart the field is weakest.

The strength of the electric field is defined as the electrostatic force experienced by a small test charge qo placed at that point divided by the charge itself. The electric field is a vector, and its direction is the same as the direction of the force on a positive test charge.

Because positive charges repel each other, the electric field around an isolated positive charge is oriented radially outward. When they are represented by lines of force, or field lines, electric fields are depicted as starting on positive charges and terminating on negative charges.

the value is set. And since the value corresponds to the predetermined direction, it is always positive. One of my international students from China used the vector argument. Since electric field is a vector quantity, can’t we 1.