Practace exam

I answered the first question right. Not willing to do ninety-nine more.

It is desired to raise the power to a speaker from 15 W to 30 W. This is a:
  1. 2 dB increase
  2. 6 dB increase
  3. 15 dB increase
  4. 3 dB increase
 
I fail. I studied dB for probably 2 days out of my entire life. I couldn't quite remember the formula, except for that it involved exponentials. As wikipedia tells me, it follows:

L(dB) = 10 log (P1/P0)

In this case: 3dB.
 
I was originally mistaken. A 10 dB increase is perceived to be twice as loud. 3 dB is usually a basis to provide headroom when you purchase an amplifier. To increase your headroom by 3 dB, you'll need to double the amount of watts you're putting out. If you want to increase your headroom by 10 dB, you'll need ten times the power.
 
The noise level in a radio receiver is generated mostly in the:
A. IF stages.
B. RF section. (CORRECT ANSWER)
C. Local Oscillator.
D. Audio section.

I got this 1st one right and stopped after looking at my second question...
 
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