Home › If the sum of the drops across the seven labeled…
If the sum of the drops across the seven labeled elements in the loop is $24\,\text{V}$, what must be the source voltage $V_s$ according to Kirchhoff's Voltage Law? 
A$0\,\text{V}$
B$12\,\text{V}$
C$24\,\text{V}$
D$48\,\text{V}$
Answer & Solution
Correct answer: C. $24\,\text{V}$
From KVL, $V_1+V_2+V_3+V_4+V_5+V_6+V_7-V_s=0$. Therefore $V_s$ must equal the total voltage drop. If the sum of the drops is $24\,\text{V}$, then $V_s=24\,\text{V}$.