Question

*R3= 9 ohms

What is the voltage drop running through resistor five?

Answer 1

The correct answer is: The voltage drop across
`R_5` is 45V.

Step-by-step explanation:
First you need to find the total current of the circuit, which is:
According to Ohm's law:

V = I * R

I = V/R --- (1)

Where
R = Total Equivalent resistance of the circuit
V = Total Voltage = 90V
I -= Total Current

First let us find the equivalent resistance:

`R = R_1 + R_2 + R_5 + (R_3*R_4)/(R_3+R_4) \\ R = 3 + 6 + 15 + (9*18)/(9+18) \\ R = 30`

Now plug in the values in (1):
(1) => I = 90/30 = 3A

Now that we have current of the circuit, we can now find the voltage drop across
`R_5` = 15 ohms using:

`V_5 = I * R_5`

Where
`V_5` is the voltage drop across resistor 5;

`V_5 = 3 * 15 = 45V`