Final answer:
To find the number of batteries needed, use Ohm's law to calculate the voltage required and then divide by the voltage of each battery. The answer is 4 batteries.
Step-by-step explanation:
To find the number of batteries needed, we can use Ohm's law, which states that the current (I) flowing through a circuit is equal to the voltage (V) divided by the resistance (R). In this case, the current required by the light bulb is 2 amps and the resistance of the bulb is 3 ohms. Using Ohm's law, we can calculate the voltage required:
V = I * R = 2 * 3 = 6 volts.
Since each battery is 1.5 volts, the number of batteries needed is:
6 volts / 1.5 volts per battery = 4 batteries.