A 15.0- resistor and a 20.0- resistor are connected in parallel. A 5.00- resistor is connected in series with this parallel arrangement. The resistors are connected across a 1.00 10^2-V battery. What is the current flowing through the 20.0- resistor?

IS it 3.15 A?

I got it like this :

two in parallel are equal to 15*20/35 = 8.57 ohms
that in series with 5 ohms gives you 13.57 ohms

I = E/R = 100/13.57 = 7.37 amps total current.

voltage across parallel combo is E = IR = 7.37 x 8.57 = 63.1 volts
current through 20 ohms, I = E/r = 63.1/20 = 3.15

That's not what I got.

The equivalent resistance of the 20 ohm and 15 ohm resistors in parallel is, in ohms, (20 * 15)/(20 + 15). Add that to the 5 ohm resistor connected in series. Finally divide the applied voltage, 100 volts, by the total resistance to get the current.

Yes, you're right! I missed the last part that stated "through the 20.0 resistor".

Sorry about that

thanks

To calculate the current flowing through the 20.0- resistor, we need to follow a few steps:

Step 1: Calculate the equivalent resistance (Req) of the parallel combination of the 15.0- resistor and the 20.0- resistor.

The formula to calculate the equivalent resistance of two resistors connected in parallel is:

1/Req = 1/R1 + 1/R2

Substituting the values:
1/Req = 1/15.0 + 1/20.0

To compute Req, we take the reciprocal of both sides:
Req = (15.0 * 20.0) / (15.0 + 20.0)
Req = 300 / 35
Req = 8.57 -

Step 2: Calculate the total resistance (Rt) of the circuit.

The total resistance (Rt) is given by the sum of the equivalent resistance (Req) and the series resistor (5.00-).

Rt = Req + 5.00
Rt = 8.57 + 5.00
Rt = 13.57 -

Step 3: Calculate the current (I) flowing through the circuit using Ohm's Law.

The current (I) is given by the ratio of the battery voltage (V) to the total resistance (Rt).

I = V / Rt
I = 100 / 13.57
I = 7.37 -

Step 4: Calculate the current (I20) flowing through the 20.0- resistor.

Since the parallel combination splits the current, the current flowing through the 20.0- resistor will be the same as the current flowing through the 15.0- resistor and will be equal to the total current (I).

Therefore, I20 = I = 7.37 A.

Based on the calculations, the current flowing through the 20.0- resistor is approximately 7.37 A, not 3.15 A, as you mentioned.