To determine which circuit has the greatest electric current, we can use Ohm's Law, which states:
\[ I = \frac{V}{R} \]
where \( I \) is the current (in amperes), \( V \) is the voltage (in volts), and \( R \) is the resistance (in ohms).
Let's calculate the current for each circuit:
-
Circuit 1:
- Resistance (R) = 0.5 ohms
- Voltage (V) = 20 V
- Current (I) = \( \frac{20}{0.5} = 40 \) A
-
Circuit 2:
- Resistance (R) = 0.5 ohms
- Voltage (V) = 40 V
- Current (I) = \( \frac{40}{0.5} = 80 \) A
-
Circuit 3:
- Resistance (R) = 0.25 ohms
- Voltage (V) = 40 V
- Current (I) = \( \frac{40}{0.25} = 160 \) A
-
Circuit 4:
- Resistance (R) = 0.25 ohms
- Voltage (V) = 60 V
- Current (I) = \( \frac{60}{0.25} = 240 \) A
Now, let's summarize the results:
- Circuit 1: 40 A
- Circuit 2: 80 A
- Circuit 3: 160 A
- Circuit 4: 240 A
Conclusion: Circuit 4 will have the greatest electric current at 240 A.