- #1

- 326

- 3

## Homework Statement

Determine the magnitudes and directions of the currents in each resistor shown in the figure. The batteries have emfs of ##\varepsilon_1 = 9.1## V and ##\varepsilon_2 = 11.6## V and the resistors have values of ##R_1 = 15 \Omega## , ##R_2 = 33 \Omega## , and ##R_3 = 30 \Omega## .

Assume each battery has internal resistance ##1.3 \Omega##.

## Homework Equations

EMF equation: ##\varepsilon = IR##

## The Attempt at a Solution

The equations for this case are:

##\varepsilon_1 = I_1(R_1 + r) + I_2(R_2 + r)##

##\varepsilon_2 = I_3(R_3 + r) + I_2(R_2 + r)##

where ##r## is the internal resistance. I know that by junction rule, ##I_2 = I_1 + I_3##

I found that ##I_1 \approx 0.092## and ##I_3 \approx 0.13##. For ##I_2##, the value is approximately 0.22 in terms of two significant figures, but Mastering Physics marked it incorrect, indicating that I need to check my calculations. I don't know what I did wrong. 0.23 and 0.21 are also incorrect.