Learning Goal:
To practice Problem-Solving Strategy 26.2 Kirchhoff's
Rules.
(Figure 1) The circuit diagram below shows two emf
sources and a bulb connected in parallel. Also connected
in the circuit is a resistor with resistance R = 0.2 $\Omega$. The
resistance of the bulb is $R_b$ = 0.5 $\Omega$, and each of the
sources has internal resistance: $r_1$ = 0.025 $\Omega$ and $r_2$ =
0.02 $\Omega$
If $E_1$ = 13.0 V and $E_2$ = 5.0 V, calculate the current $I_2$
flowing in emf source $E_2$.
Correct
Often, you will not know in advance the actual direction of an unknown current or emf, but this doesn't
matter. If the actual direction of a particular quantity is opposite to your assumption, the result of your
calculations will come out with a negative sign.
EXECUTE the solution as follows
Part B
Calculate the current $I_2$ flowing in emf source $E_2$
Express your answer in amperes to three significant figures.
$I_2$= 22.6 A
Correct
EVALUATE your answer
Part C
A useful strategy to evaluate your answer is to consider a loop other than the ones you used to solve the problem; if
the sum of potential drops around this loop isn't zero, you made an error somewhere in your calculations. Begin by
calculating the current $I_1$ flowing through the emf source $E_1$.
Express your answer in amperes to three significant figures.
Figure
$r_1$ $E_1$
$r_2$ $E_2$
$R$
$R_b$
