Answer:
The magnetic field at a distance of 19.8 cm from the wire is 1.591 mT
Explanation:
Given;
first magnetic field at first distance, B₁ = 2.50 mT
first distance, r₁ = 12.6 cm = 0.126 m
Second magnetic field at Second distance, B₂ = ?
Second distance, r₂ = ?
Magnetic field for a straight wire is given as;

Where:
μ is permeability
B is magnetic field
I is current flowing in the wire
r distance to the wire

Therefore, the magnetic field at a distance of 19.8 cm from the wire is 1.591 mT
2 seconds,,,,,,,,,,,,,,,,,,,,,,,
B. Yard
the other answers C. & D. are metric A is a unit of temperature