Describe the internals of a light-emitting diode (LEO). Describe what happens internally when sufficient current is applied to activate LED. 

What isthe device pictured? What purpose does it serve in an electrical circUit?-

Describe the action of the device as shown in the two diagrams.

NEC permits metal wireways for most industrial locations except where they can be exposed to severe physical damage or a corrosive environment. Where physical damage might occur, what additionally must be done to protect the wireway or conduit?

What single action indicates to you that the wire nut you're using to make a splice is either too large or too small? What indicates to you that it's the right size?

Describe the difference in usage between straight-bladed plugs and locking plugs.