A circuit is constructed with five resistors and one real battery as shown above
ID: 1450378 • Letter: A
Question
A circuit is constructed with five resistors and one real battery as shown above right. We model. The real battery as an ideal emf V = 12 V in series with an internal resistance r as shown above left. The values for the resistors are: R1 = R3 = 51 , R4 = R5 = 68 and R2 = 117 . The measured voltage across the terminals of the batery is Vbattery = 11.64 V.
1)
What is I1, the current that flows through the resistor R1?mA
2)
What is r, the internal resistance of the battery?
3)
What is I3, the current through resistor R3?mA
4)
What is P2, the power dissipated in resistor R2?W
5)
What is V2, the magnitude of the voltage across the resistor R2?V
6)
Resistor R2 is now shorted out as shown. How does the magnitude of the voltage across the battery change?
Vbattery decreases
Vbattery increases
Vbattery remains the same
Numbers 5 & 6 are supposed to be tricky, so plaese answer only if you are sure. (I can't check the answer for them until they are graded )
Explanation / Answer
(1)
Req of the circut,
Req = R1 + 1/(1/R2 + 1/(R3+R4+R5))
Req = 51 + 1/(1/117 + 1/(51+68+68))
Req = 123
I = V/Req = 11.64/123
I = 94.6 mA
Current that flows through the resistor R1, = 94.6 mA
(2)
r = (12.0 - 11.64)/(94.6*10^-3)
r = 3.8
Internal resistance of the battery, 3.8
(3)
I2 * 117 = I3 * (51+68+68)
I2 + I3 = 94.6 mA
Solving these eq,
I3 = 36.4 mA
Current through resistor R3, I3 = 36.4 mA
(4)
P2 = I2^2 * R2
P2 = (58.2*10^-3)^2 * 117 W
P2 = 0.396 W
Power dissipated in resistor R2, = 0.396 W
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.