True or False: Battery-operated smoke detectors and 120-volt smoke detectors are both common types.

Both battery-operated smoke detectors and 120-volt smoke detectors serve the critical purpose of enhancing safety by detecting smoke and potential fires. This makes them common types found across various residential and commercial settings.

Battery-operated smoke detectors are favored for their ease of installation and flexibility, as they do not require hardwiring and can be placed in various locations without the need for electrical outlets. They are ideal for areas where running electrical wiring might be difficult or in homes without existing electrical systems.

On the other hand, 120-volt smoke detectors are typically hardwired into the home's electrical system, providing a constant power source and often featuring battery backup systems to ensure reliability during power outages. These are frequently found in newer homes and commercial buildings where a continuous power supply is critical.

Since both types are prevalent in homes and businesses, the assertion that "both battery-operated smoke detectors and 120-volt smoke detectors are common types" accurately reflects their widespread use in ensuring fire safety.