In a series circuit, one of the resistors is replaced with a resistor having a lower resistance value. how does this affect the current in the circuit?

The current in the circuit isn't affected i.e it remains the same

Explanation:

In a series connected circuit, same current flows across the resistors bit different voltage is passed across them. This means that no matter the value of the resistance in a series connected circuit, the current flowing through the resistors will remain the same.

Based on the above conclusion, if one of the resistors is replaced with a resistor having a lower resistance value in a series circuit, the current in the circuit will not be affected.

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