The current right before it comes back to the battery is still 0.5 A as the circuit is a series circuit and the current in a series circuit remains constant throughout the circuit.
To find the current right before it comes back to the battery when it travels through a 100 ohm, 200 ohm, and 300 ohm resistors all in series, follow these steps:
1. Calculate the total resistance of the circuit:
Total Resistance (Rt) = R1 + R2 + R3
Rt = 100 ohm + 200 ohm + 300 ohm
Rt = 600 ohm
2. Apply Ohm's Law to find the current:
Ohm's Law states that Voltage (V) = Current (I) × Resistance (R)
In this case, you know the current leaving the battery (0.5 A) and the total resistance (600 ohm), so you can calculate the voltage across the entire circuit:
V = I × R
V = 0.5 A × 600 ohm
V = 300 V
3. Now, since the resistors are in series, the current remains constant throughout the entire circuit. Therefore, the current right before it comes back to the battery is the same as the current leaving the battery, which is 0.5 A.
So, the current right before it comes back to the battery after traveling through the 100 ohm, 200 ohm, and 300 ohm resistors in series is 0.5 A.