# Question Which device can be used to directly reverse two power lines? **Options:** 1. Selector switch 2. Toggle switch 3. Push button 4. None of the answers above is correct --- # Step-by-Step Solution ## 1. Understanding the Question - "Reverse two power lines" means swapping their connections, commonly to reverse the direction of a motor or phase sequence. - The question asks which device can be used **directly** (without additional components or wiring) for this purpose. ## 2. Analyzing Each Option ### Option 1: Selector Switch - A selector switch can have multiple positions and poles. - **A double-pole double-throw (DPDT) selector switch** can swap two wires directly by changing its position. - Often used in control panels to reverse motor direction by swapping connections. ### Option 2: Toggle Switch - A toggle switch is a simple on/off switch. - Unless specially configured (as a DPDT toggle), **a standard toggle switch cannot swap two lines directly**. - Some toggle switches are DPDT, but the term "toggle switch" generally means a simple circuit on/off control. ### Option 3: Push Button - A push button only temporarily makes or breaks a circuit. - It cannot swap connections on its own. ### Option 4: None of the answers above is correct - If none of the above switches can be used, this would be the answer. - But as explained, a selector switch **can** do this, if it is the appropriate type. ## 3. Conclusion - The **selector switch** (option 1) can be used to directly reverse two power lines, assuming it is a DPDT or similar type. --- # Final Answer **1) Selector switch** A selector switch (specifically a DPDT type) can be used to directly reverse two power lines. --- **Summary Table** | Option | Can reverse lines? | Notes | |---------------------|-------------------|--------------------------------| | Selector switch | Yes | Must be DPDT or similar | | Toggle switch | No (unless DPDT) | Usually just makes/breaks | | Push button | No | Only makes/breaks circuit | | None of the above | No | |