Question

What is the total voltage supplied by the battery? (must include unit - V)

Answer 1

Answer:

$\rm 100\; V$.

Explanation:

The battery here is connected to three resistors. Because these resistors are connected in series:

• the voltage supplied by the battery is the sum of the voltage across each of the three resistors.
• the current across the three resistors is the same.

The voltmeter on the right reads $20\; \rm V$. Since this voltmeter is connected in parallel with $R_2$, it measures the voltage across

The voltage across $R_1$ and $R_3$ can be found with Ohm's Law. Note that the ammeter on the lower-right corner reads $2\; \rm A$. Because this circuit is connected in series, the current through each of its three resistors in would all be

• $R_1 = 15\; \Omega$. $I_1 = 2\; \rm A$. By Ohm's Law, $V_1 = I_1 \cdot R_1 = 2\; \rm A \times 15 \; \Omega = 30\; \rm V$.
• $R_3 = 25\; \Omega$, $I_3 = 2\; \rm A$. By Ohm's Law, $V_3 = I_3\cdot R_3 = 2\; \rm A \times 25\; \rm \Omega = 50\; \rm V$.

Since the three resistors are connected in series:

$\begin{aligned}& V(\text{from battery})\\ &= V(\text{across circuit}) \\ &= V_1 + V_2 + V_3 \\&= \rm 30\; V + 20 \; V + 50 \; V \\&= 100\; \rm V\end{aligned}$.