Question

For the current loops shown in the figure, Kirchhoff's loop rule for the loops $A H D C B A$ and AHDEFGA yields these equations respectively

• A. $-30 I_{1}-41 I_{3}+45=0$ and $-30 I_{1}+21 I_{2}-80=0$
• B. $30 I_{1}-41 I_{3}+45=0$ and $30 I_{1}-21 I_{2}-80=0$
• C. $30 I_{1}+41 I_{3}-45=0$ and $-30 I_{1}+21 I_{2}+80=0$
• D. None of the above

Answer 1

Answer: (D)

Applying Kirchhoff's loop rule for the closed loop $A H D C B A$

$-30 I_{1}-45-40 I_{3}-I_{3}=0$
$-30 I_{1}-45-41 I_{3}=0$
Applying Kirchhoff's loop rule for closed loop AHDEFGA
$-30 I_{1}+20 I_{2}+I_{2}-80=0$
$-30 I_{1}+21 I_{2}-80=0$