FCC Technician Exam Question Of The Day (T5B09)

Q) What is the approximate amount of change, measured in decibels (dB), of a power increase from 5 watts to 10 watts?

A) 3 dB

NJ2X Notes:
The following formula will allow you calculate the ratio in decibels given two different power values.

dB = 10 * Log(Pa / Pb)

Using the figures in the question:
dB = 10 * Log (10 / 5)
dB = 10 * Log(2)
dB = 10 * 0.301
dB = 3.01
which is approximately 3 dB



This question is from the FCC Element 2 Technician Class Question Pool
Effective July 1, 2010 for examinations and is valid until June 30, 2014

Popular Posts