What is the most likely reason a bulb does not light?

What is the most likely reason a bulb does not light?

• A. Loose connection
• B. Burnt out battery
• C. Broken filament
• D. Wrong polarity

Answer: (C)

In a simple circuit, the bulb lights only if there is a continuous path for current through the filament. If the filament is broken, the circuit becomes open and no current can flow, so the bulb cannot glow. That direct interruption of the current path is why a broken filament is the most likely reason the bulb doesn’t light. A loose connection could stop lighting as well, but it would often cause flickering or intermittent light rather than a complete absence of light. A burnt-out battery would remove the power source, but when the power is available, the filament itself must conduct for light to appear, and a broken filament directly stops that. Wrong polarity doesn’t matter for an incandescent bulb, since it has no polarity sensitivity—the filament will glow with either direction of current.

In a simple circuit, the bulb lights only if there is a continuous path for current through the filament. If the filament is broken, the circuit becomes open and no current can flow, so the bulb cannot glow. That direct interruption of the current path is why a broken filament is the most likely reason the bulb doesn’t light. A loose connection could stop lighting as well, but it would often cause flickering or intermittent light rather than a complete absence of light. A burnt-out battery would remove the power source, but when the power is available, the filament itself must conduct for light to appear, and a broken filament directly stops that. Wrong polarity doesn’t matter for an incandescent bulb, since it has no polarity sensitivity—the filament will glow with either direction of current.