In the circuit in the figure below, the batteries have negligible internal resis
ID: 1601370 • Letter: I
Question
In the circuit in the figure below, the batteries have negligible internal resistance. (Take R1 = 3.10 , R2 = 3.60 , and R3 = 6.80 .)
(b) Find the magnitude of the potential difference between points a and b.
____ V
(c) Find the power supplied by each battery.
Explanation / Answer
from junction rule
I2 + I1 = I3 (1)
from loop rule:
12 - R2I2 + R1I1 - 12 = 0
R1I1 = R2I2
3.1 I1 = 3.6 I2
I1 = 1.16 I2 (2)
12 - I1R1 - R3I3 = 0
12 - 3.1I1 - 6.8I3 = 0
12 - 3.1I1 - 6.8(I2 + I1) = 0
12 - 3.1 I1 - 6.8I2 - 6.8I1 = 0
12 - 6.8 I2 - 9.9I1 = 0
12 - 6.8 I2 - 9.9 x 1.16 I2 = 0
I2 = 0.66 A
I1 = 1.16 x 0.66 = 0.77 A
I3 = 0.66 + 0.77 = 1.43 A
Hence, I(3.1) = 0.77 A ; I(3.6) = 0.66 A ; I(6.8) = 1.43 A
b)Vab = I3R3
Vab = 1.43 x 6.8 = 9.72 V
Hence, Vab = 9.72 V
c)P(left) = 12 x 0.66 = 7.92 W
P(left) = 7.92 W
P(right) = 12 x 0.77 = 9.24 W
P(right) = 9.24 W