Set up a parallel circuit with three resistors. Set up the battery to be 9 V, one resistor at 10 Ohms, the other at 21 Ohms, and the last at 13 Ohms. What is the equivalent resistance of this circuit? What is the average current of the circuit?

In a parallel circuit, the equivalent resistance is the reciprocal of (the sum of the individual reciprocals).

1/R = 1/10 + 1/21 + 1/13

1/R = 0.225 mhos

R = 4.45 ohms

I = V / R

The total current out of the battery is

I = (9v)/(4.45ohms)

I = 2.02 Amperes

As the total current leaves the battery, it splits into 3 paths, and each resistor gets part of it. The 10ohm resistor gets the most current; the 21ohm resistor gets the least current. After flowing through the resistors, the 3 currents join and add up to 2.02 Amperes again, and the same current returns to the battery.

Each resistor has the same 9v of EMF across it.

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