Question

The DC power source for arc welding has the characteristics \( 3V + I = 240 \), where 'V' is the voltage in volts and 'I' is the current in amperes. For maximum power at the electrode, voltage should be set at:

• A. 40 V
• B. 140 V
• C. 220 V
• D. 240 V

Hint:

To maximize power in electrical systems, the voltage and current must be chosen to balance the equation \( P = V \times I \).

Answer 1

The Correct Option is B

Step 1: Use the power equation.
The power \( P \) is given by: \[ P = V \times I \] The equation for the voltage and current is: \[ 3V + I = 240 \] Step 2: Maximize power To maximize power, we need to find the voltage and current that give the highest value of \( P = V \times I \). This happens when \( \frac{dP}{dV} = 0 \). Step 3: Conclusion By solving the equation, the optimal voltage is \( 140 \, \text{V} \). Final Answer: \[ \boxed{140 \, \text{V}} \]