Final answer:
The question is about calculating the magnetic field strength around a conductor and understanding the force between parallel current-carrying wires. The magnetic field strength can be found using the Biot-Savart law, and the force's nature (attractive or repulsive) depends on the currents' direction in the wires.
Step-by-step explanation:
The student's question pertains to the magnetic field generated by electrical current in a conductor, which is a concept from Physics, specifically electromagnetism. The strength of the magnetic field around a straight conductor carrying current can be calculated using Ampère's law and the Biot-Savart law. The magnetic field (B) at a distance (r) from a long straight wire carrying current (I) is given by the equation B = (μ0 · I) / (2π · r), where μ0 is the permeability of free space (4Π x 10^-7 T·m/A). Using this equation with the provided current of 70 A and a distance of 2.1 cm from the cable, we can calculate the magnetic field strength.
For the question about the force per meter between two wires of a jumper cable, we can use Ampère's force law, which describes the mutual attraction or repulsion between parallel wires carrying currents. The law states that the force per meter is proportional to the product of the currents in the wires and inversely proportional to the distance between them. This question also seeks to know if the force is attractive or repulsive, which depends on the direction of the currents in the two wires. When currents flow in the same direction, the force is attractive; if they flow in opposite directions, the force is repulsive.