🔍 Key Concepts

• Relationship between current in a coil and creation of a magnetic field • How a mechanical contact can be moved without direct human action • Difference between electromagnetic and electrostatic devices

💭 Think About

• Which option actually involves a coil with current creating a force to move contacts? • Which options describe things that sound more like static charge or stored energy rather than a typical relay? • Think about what happens inside a common control relay when you energize and de-energize it.

✅ Before You Answer

• Identify which choice clearly mentions current and a coil together • Eliminate any choice that focuses on permanent fields or capacitors, since generic control relays are usually not built that way • Make sure the description matches what happens when a relay picks up (energized) and drops out (de‑energized) in a control circuit