Which statement correctly describes spark discharge?

• A. It is the least common type of electrostatic discharge
• B. It is the most common type of electrostatic discharge in industry
• C. It occurs only in high humidity
• D. It requires a spark gap to form

Answer: (B)

Spark discharge is a rapid breakdown of air across a gap when the electric field becomes strong enough to ionize the air, creating a conductive channel and a bright, brief current path. In industry, many processes involve charged surfaces (powders, plastics, components) and nearby grounded paths, so the air between them can break down frequently, making this type of discharge the most common electrostatic discharge seen on the factory floor.

The other statements don’t fit as well: spark discharges aren’t rare, humidity doesn’t require them (higher humidity generally reduces static buildup by increasing air conductivity), and while a gap is involved, that alone isn’t what defines spark discharge—the key is breakdown across air leading to a visible spark and high current.