Question

which one of the following best describes a key difference between arc welding and gas welding compared to other types of welding?
a other welding methods, such as resistance welding and ultrasonic welding, require shielding gas, just like arc and gas welding.

b arc welding and gas welding both require filler metal to create a weld, whereas other welding methods do not.

c arc welding uses electricity to create heat, while gas welding relies on a flame, unlike resistance or friction welding.

d arc welding and gas welding both use electrical power to generate heat, while other weld-

Explanation:

• Option A: Resistance and ultrasonic welding do not typically require shielding gas, so A is incorrect.
• Option B: Many other welding methods (e.g., some resistance welding) can use filler metal, so B is wrong.
• Option C: Arc welding uses electrical energy for heat, gas welding uses a flame (from gas combustion), and resistance/friction welding have different heat - generation mechanisms (resistance uses electrical resistance, friction uses mechanical friction). This accurately describes a key difference.
• Option D: Gas welding does not use electrical power to generate heat (it uses a gas - fueled flame), so D is incorrect.

Answer:

C. Arc welding uses electricity to create heat, while gas welding relies on a flame, unlike resistance or friction welding.