Base used for decibel logarithms.

Base used for decibel logarithms.

• A. Base 2
• B. Base 10
• C. Base e
• D. Base 3

Answer: (B)

The decibel scale uses a ten-based logarithm to express ratios of power or amplitude. For power, the formula is dB = 10 log10(P/P0); for voltage (or current) with the same impedance, it’s dB = 20 log10(V/V0) because power is proportional to voltage squared. Using base 10 makes common changes easy to read: a tenfold increase in power corresponds to +10 dB, and a tenfold increase in voltage corresponds to +20 dB. Historically, this base comes from the bel unit, with one tenth of a bel equal to one decibel. Other bases would yield less intuitive numbers, so base 10 is standard.

The decibel scale uses a ten-based logarithm to express ratios of power or amplitude. For power, the formula is dB = 10 log10(P/P0); for voltage (or current) with the same impedance, it’s dB = 20 log10(V/V0) because power is proportional to voltage squared. Using base 10 makes common changes easy to read: a tenfold increase in power corresponds to +10 dB, and a tenfold increase in voltage corresponds to +20 dB. Historically, this base comes from the bel unit, with one tenth of a bel equal to one decibel. Other bases would yield less intuitive numbers, so base 10 is standard.