Final answer:
The battery voltage in this circuit with a 20-ohm resistor and a current of 2 amps is 40 volts.
Step-by-step explanation:
In order to find the battery voltage, we can use Ohm's Law, which states that voltage (V) is equal to current (I) multiplied by resistance (R). In this case, the resistance is 20 ohms and the current is 2 amps. Using the formula V = IR, we can calculate the battery voltage as follows:
V = 2A * 20Ω = 40V