Which layer of the OSI model covers physical cable connections?

Assume that the optical power transmitted by a 62.5/125 multimode fiber is distributed uniformly across its core. If this fiber is perfectly coupled (i.e., the two fibers are aligned and abutted) to a 50/125 fiber, what is the percent of power that is lost?

Which electrical characteristic is displayed with the correct preferred value?

You are designing a firestop system for a hospital with several floors that have isolation rooms. Air leakage control is important to ensure rooms are sealed and restrict the spread of disease. Which firestop test rating should you use to ensure air leakage compliance?

The ability of a device to withstand electromagnetic disturbances from another device is: