Find the following currents. The current I1 through the resistor of resistance R1 = 15.0 Ω . The current I2 through the resistor of resistance R2 = 45.0 Ω . The current I3 through the resistor of resistance R3 = 20.0 Ω . The current I4 through the resistor of resistance R4 = 25.0 Ω .

Explanation:

Assuming the circuit is the shown in the attached image, where:

We can use the 2nd Kirchoff Law (or Voltage Law) for each section of the circuit:

1st section:

2nd section:

Now, according to Ohm's Law, the voltage is equal to the multiplication of the current and the resistance :

Then:

1st section:

(1)

2nd section:

(2)

In this case the same current that gous trhough is the same that goes through , since they are in series.

And according to 1st Kirchoff Law (or Current Law):

(3)

At this point we have a system with three equations. Let's begin by substituting (3) in (1):

(4)

Applying common factor :

(5)

Isolating from (2):

(6)

Rewriting with the known values:

(7)

(8)

Substituting (8) in (5):

(9)

Isolating :

(10)

Rewritting with the known values;

(11)

(12)

Then:

Substituting (12) in (3):

(13)

(14)

unbalanced force

explanation:

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it