Step 1: Understanding the Concept:
Arc welding is a process that uses an electric arc to create intense heat to melt and join metals. The electric arc is a discharge of electricity across a gap between an electrode and the workpiece. The question asks for the typical voltage across the arc {during} the welding process.
Step 2: Detailed Explanation:
1. An arc welding power source has two important voltage ratings:
Open Circuit Voltage (OCV): This is the voltage across the output terminals of the welding machine when no welding is being done (the arc has not been struck). The OCV needs to be high enough to initiate or "strike" the arc easily. For most Shielded Metal Arc Welding (SMAW) machines, the OCV is typically in the range of 50-100V.
Arc Voltage (or Operating Voltage): This is the voltage across the arc {while} welding is in progress. Once the arc is established, it has a relatively low electrical resistance. According to Ohm's Law, for a high current to flow through this low resistance, the voltage must drop significantly from the OCV.
2. The typical arc voltage during welding is quite low, generally ranging from 15V to 40V, depending on the welding process, arc length, and type of electrode.
3. Let's look at the options:
(A) 30-40V: This range falls squarely within the typical operating arc voltage for many common arc welding processes.
(B) 80-100V: This is the typical range for the {open circuit voltage}, not the operating voltage.
(C) 120-150V and (D) 400-440V: These voltages are much too high for standard arc welding and are in the range of mains supply or industrial power, not the arc voltage itself.
4. The provided key indicates (B) 80-100V. This is factually incorrect for the {operating} arc voltage. As explained, 80-100V is the open-circuit voltage required to start the arc. The voltage drops to the 15-40V range once the arc is running. The question "Arc welding is carried out with a voltage of" is ambiguous, but most commonly refers to the operating voltage. If the question meant the OCV of the machine, then (B) would be correct. Given the ambiguity, and the potential for confusion between OCV and arc voltage, this is a poorly formulated question. However, based on the provided key, the question is likely asking for the open-circuit voltage.
Solution based on provided key (interpreting question as OCV):
To initiate an electric arc for welding, a sufficiently high voltage is required to break down the air gap between the electrode and the workpiece. This initial voltage, supplied by the welding machine when no current is flowing, is called the Open Circuit Voltage (OCV). For common arc welding processes, the OCV is typically in the range of 50V to 100V. Once the arc is established, the voltage drops to a much lower value (the arc voltage). Since 80-100V is a standard OCV range, and it is listed as the correct answer, it is presumed the question is referring to this aspect.
Step 3: Final Answer (following the provided key):
The open-circuit voltage of an arc welding machine, required to strike the arc, is typically in the range of 80-100V. Therefore, option (B) is the intended answer.