a 100 V DC signal is applied to four resistors as shown in Fig. 5. The values of the resistors are 20 ohm, 40 ohm, 60 ohm and 80 ohm. What is the voltage across the 40 ohm resistor?
100v
E = 100 Vdc
R1 = 20 Ohms
R2 = 40 Ohms
R3 = 60 Ohms
R4 = 80 Ohms
V2 = ?
If the resistors are connected in series,
I = E/(R1+R2+R3+R4)
V2 = I*R2
fefw
To find the voltage across the 40 ohm resistor, we need to determine the current flowing through it. We can use Ohm's Law, which states that the voltage across a resistor is equal to the current through it multiplied by its resistance.
To find the current, we need to calculate the total resistance of the circuit. In this case, the resistors are connected in series, so we can simply add their resistances: 20 ohm + 40 ohm + 60 ohm + 80 ohm = 200 ohm.
Next, we can use Ohm's Law again to calculate the current. Ohm's Law states that the current flowing through a circuit is equal to the voltage applied divided by the total resistance. In this case, the voltage applied is 100 V and the total resistance is 200 ohm, so the current is:
I = V / R
I = 100 V / 200 ohm
I = 0.5 A
Now that we know the current flowing through the circuit is 0.5 A, we can find the voltage drop across the 40 ohm resistor using Ohm's Law again:
V = I * R
V = 0.5 A * 40 ohm
V = 20 V
Therefore, the voltage across the 40 ohm resistor is 20 volts.