Final answer:
The magnetic field at point P due to a straight current-carrying wire can be calculated using Ampère's law, which gives the formula B = (µ₀∙I)/(2π∙R). The strength depends on the current I and the distance R from the wire to point P, and it assumes no interferences from other fields.
Step-by-step explanation:
To calculate the magnetic field at point P due to an infinitely long straight wire carrying a current I, we can use Ampère's law, which relates the magnetic field around a conductor to the current flowing through the conductor. According to this law, the magnetic field (B) at a distance R from the wire is given by the formula B = (µ₀∙I)/(2π∙R), where µ₀ is the permeability of free space (µ₀ = 4π x 10⁻⁷ T·m/A), I is the current, and R is the radius from the wire to the point where the magnetic field is being calculated.
Using the given values I = 6.0 A, r1 = 1.2 cm, and r2 = 2.4 cm, we can carry out the calculation for the strength of the magnetic field at point P using the radii r1 and r2 as distances R1 and R2 from wire 1 and wire 2, respectively. If the wires carry current in the same direction, the net magnetic field at P will be the sum of the individual fields. If the currents are in opposite directions, the fields will subtract.
It's important to note that this question is based on theoretical models and assumes that other magnetic fields and effects (such as Earth's natural magnetic field) are negligible or can be ignored.