What will be the mass of each of these wires

The field due to at a distance r is. This field is uniform from the wire 1 and perpendicular to it, so the force it exerts on a length l of wire 2 is given by with. Substituting the expression for into Figure and rearranging terms gives. The force is attractive if the currents are in the same direction and repulsive if they are in opposite directions.

This force is responsible for the pinch effect in electric arcs and other plasmas. The force exists whether the currents are in wires or not. It is only apparent if the overall charge density is zero; otherwise, the Coulomb repulsion overwhelms the magnetic attraction.

In an electric arc, where charges are moving parallel to one another, an attractive force squeezes currents into a smaller tube. In large circuit breakers, such as those used in neighborhood power distribution systems, the pinch effect can concentrate an arc between plates of a switch trying to break a large current, burn holes, and even ignite the equipment.

Another example of the pinch effect is found in the solar plasma, where jets of ionized material, such as solar flares, are shaped by magnetic forces. The definition of the ampere is based on the force between current-carrying wires. Note that for long, parallel wires separated by 1 meter with each carrying 1 ampere, the force per meter is.

Since is exactly by definition, and because the force per meter is exactly This is the basis of the definition of the ampere. Infinite-length wires are impractical, so in practice, a current balance is constructed with coils of wire separated by a few centimeters. Force is measured to determine current. This also provides us with a method for measuring the coulomb.

We measure the charge that flows for a current of one ampere in one second. That is, For both the ampere and the coulomb, the method of measuring force between conductors is the most accurate in practice. Calculating Forces on Wires Two wires, both carrying current out of the page, have a current of magnitude 5.

The first wire is located at 0. Attracted by both? Figure 2. Three parallel coplanar wires with currents in the outer two in opposite directions. Suppose two long straight wires run perpendicular to one another without touching.

Does one exert a net force on the other? If so, what is its direction? Does one exert a net torque on the other? Justify your responses by using the right hand rules. Use the right hand rules to show that the force between the two loops in Figure 3 is attractive if the currents are in the same direction and repulsive if they are in opposite directions. Is this consistent with like poles of the loops repelling and unlike poles of the loops attracting? Draw sketches to justify your answers.

Figure 3. Two loops of wire carrying currents can exert forces and torques on one another. If one of the loops in Figure 3 is tilted slightly relative to the other and their currents are in the same direction, what are the directions of the torques they exert on each other?

Does this imply that the poles of the bar magnet-like fields they create will line up with each other if the loops are allowed to rotate? Electric field lines can be shielded by the Faraday cage effect. Can we have magnetic shielding? Can we have gravitational shielding? What is the magnitude and direction of the force between The force per meter between the two wires of a jumper cable being used to start a stalled car is 0.

What is the direction and magnitude of the current in the other wire? Ab aap Whatsapp pe solutions paa saktey h, hum aapko ping karenge. Study Materials. Why use Doubtnut? Instant Video Solutions. Request OTP. Updated On: Share This Video Whatsapp. Text Solution. Answer :.