Yes
No, from what I understand the line out on a guitar amp puts out a hotter signal than an instrument (your guitar for example) and shouldn't be run into another amplifier's input jack. The Line out jack is designed to be run into a PA or a mixer. Your best bet is an A/B/Y box to run both amps simultaneously.
your question is very badly phrased... you dont install a pedal onto an amp. but if you mean you want to use a guitar pedal on a 15 watt amp, of course you can!
The Pyle PPG-260A 80-Watt Portable Guitar Amplifier is a good choice for any condition, outside, kitchen, garage, anywhere.
The most common decibel used in guitar amps would be 95 and 100 decibels. This would usually be a 60 watt amplifier.
A 15 watt Spider 3 amplifier is for practice, and in that capacity works fine with any good guitar -- including a Stratocaster or Epiphone. For a practice amplifier to use with a bass guitar, you would want to have at least 30 watts -- like a B-DEC 30.
I own a 300 watt guitar/bass a.f. amplifier labled EMC B-200. Can find no information on it.
yes/no
watt is a unit of measure. Units of measure don't make sounds.
In watt watt watts
Yes it can. The rated power of the speakers is the MAXIMUM that can be applied. If more power is supplied, damage can occur. Either the speech coil can blow or mechanical damage to the cone or suspension units.As the amplifier is below this rating, it will not supply more power than the speakers can handle and will be perfectly safe.
No, 15 watt speakers are rated far to low to be used with an external amplifier.
A 5000 watt digital monobloc amplifier is good for competition cars. The ICBM Giant 5000 watt is a favorite right now.