Answer:
0.20 G
Step-by-step explanation:
The given parameters are;
The magnetic field strength of planet X = 0.70 G
The location of a probe in relation to the vertical wire = 50 m
The measurement of a probe placed 50 mm east of a vertical wire = 0.50 G
The location of the probe = 20 mm east of the vertical wire
Based on the given parameter, the wire is a current carrying conductor with a magnetic field acting tangent to the magnetic field lines.
Given that the measured Earth magnetic field reduces, we have that the magnetic field of the wire cancels the magnetic field of the Earth
As the probe moves closer to the wire the measured magnetic field in the southern direction reduces
When the probe is placed 20 mm from the wire, the magnetic field reduces to 20/50 × 0.50 G = 0.20G