# Step-by-Step Solution ## Understanding the Question We are asked: **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 above ## What Does "Reverse Two Power Lines" Mean? - *Reversing two power lines* means swapping their connections. - This is commonly done in motors to reverse direction—for example, swapping L1 and L2 (or positive and negative) in a DC circuit, or two phases in a three-phase AC motor. ## Analysis of Options ### 1. Selector Switch - A selector switch can have multiple positions and can be wired to swap connections. - In industrial settings, selector (rotary) switches are used to reverse motor direction by swapping two phases. - **This is a correct device for direct reversal.** ### 2. Toggle Switch - A toggle switch is a simple on-off device. - Standard toggle switches do not swap or reverse connections; they just break or make the circuit. - Special toggle switches (like double-pole, double-throw or DPDT) could be wired to reverse connections, but the term "toggle switch" alone usually refers to a basic switch. ### 3. Push Button - A push button is a momentary switch, usually for starting or stopping a circuit. - It does not swap or reverse connections. ### 4. None of the above - At least one device fits; thus, this is not correct. ## Final Answer **The correct answer is:** ``` 1) Selector switch ``` **Explanation:** A selector switch can be used to directly reverse two power lines by swapping their connections, commonly for motor direction control. --- **Summary Table** | Device | Can directly reverse two power lines? | |------------------|:-------------------------------------:| | Selector switch | Yes | | Toggle switch | No (not directly) | | Push button | No | | None | No | **Final Answer:** **Selector switch (Option 1)**