some basic questions ..... i want to prepare my interview.

i know about the given things but i want more basics and interesting phenomena of these things .
what is transistor?
what is diode?
what is the difference between transistor and diode?
what is LVD?
what is difference between capacitor and inductor?
what is current ?
what is voltages ?
difference between current and voltages?
what is transformer?
what is motor ?
what is relay?
difference between time period and time delay?
what is signal?
and tell me some more basic questions ?

Open Google and search for "transistor", "diode" etc. Check wikipedia page of all these.