Planet X has a magnetic field with strength 0.70 G in the southern direction. When a probe is placed 50 mm east of a vertical wire it measures a field of 0.50 G in the southern direction. What would a probe read if placed 20 mm east of the vertical wire?

0.20 G

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

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia