A signal travels through a transmission medium and its power is reduces to one forth. Calculate the attenuation.
In optics, attenuation is related to the ratio of the input power to the output power of the signal. The equation for attenuation is:
Attenuation (dB) = 10 * log( input power / output power )
According to the problem statement, input power / output power = 1/4
Attenuation (dB) = 10 * log( input power / output power ) = 10 log( 1/4 ) = 10 * -0.6 = -6 dB.