Question

5 what can be concluded from the fact that ac power grids are widely used today? a ac systems are very expensive b only alternating current can power a city c ac systems are more efficient than dc systems d thomas edison preferred ac systems

Explanation:

• Option A: If AC systems were very expensive, they wouldn't be widely used, so A is incorrect.
• Option B: DC can also be used to power a city (e.g., in some local setups or with converters), so "only AC" is wrong, B is incorrect.
• Option C: AC power grids are widely used because AC is more efficient for long - distance transmission (can be stepped up/down with transformers), making it better for grid - scale power distribution. So this option is reasonable.
• Option D: Thomas Edison preferred DC systems, not AC, so D is incorrect.

Answer:

C. AC systems are more efficient than DC systems