Which statement about static electricity and thunderstorms is true?

• A. Lightning is a natural display of static electricity.
• B. Power lines can generate static electricity.
• C. Static electricity never discharges.
• D. Lightning never occurs in thunderclouds.

Answer: (A)

When a thunderstorm forms, charges build up in the cloud through collisions and frictions among water droplets and ice particles, causing the upper part of the cloud to become positively charged and the lower part (and sometimes the ground) to become negatively charged. The huge difference in charge creates a strong electric field, and when the air can no longer insulate the charges, it breaks down and a rapid discharge occurs. That discharge is lightning. This is a direct demonstration of static electricity in action: a buildup of electrical charges that remains separated until it finds a path to equalize.

Lightning happens specifically in thunderclouds because those clouds are where the charge separation most strongly occurs, setting up the conditions for a discharge. Other statements don’t fit: power lines don’t generate static electricity in the sense of creating the storm’s charge separation, static electricity does discharge (often as a spark or arc), and lightning certainly can occur in thunderclouds.