A standard measurement tool used to report changes in weakening or amplification.

A standard measurement tool used to report changes in weakening or amplification.

• A. Hertz scale
• B. Lux scale
• C. Decibel notation
• D. Voltmeter

Answer: (C)

The main idea here is expressing how much a signal has been amplified or attenuated using a logarithmic ratio unit. Decibel notation compares a signal to a reference level and turns ratios of power (or amplitude) into a manageable number. It’s the standard because it works well across huge ranges of values, and gains from multiple stages simply add in decibels, making it easy to see total amplification or loss. In practice, a positive dB change means amplification, while a negative dB change means weakening. For example, doubling power corresponds to about +3 dB, and if you cascade two stages of gains, you sum their dB values for the overall change. The decibel is a relative measure, so it describes changes, not absolute levels. The other options don’t fit because Hertz measures frequency, Lux measures light intensity, and a voltmeter reads voltage rather than a standard for reporting relative changes in amplification.

The main idea here is expressing how much a signal has been amplified or attenuated using a logarithmic ratio unit. Decibel notation compares a signal to a reference level and turns ratios of power (or amplitude) into a manageable number. It’s the standard because it works well across huge ranges of values, and gains from multiple stages simply add in decibels, making it easy to see total amplification or loss.

In practice, a positive dB change means amplification, while a negative dB change means weakening. For example, doubling power corresponds to about +3 dB, and if you cascade two stages of gains, you sum their dB values for the overall change. The decibel is a relative measure, so it describes changes, not absolute levels.

The other options don’t fit because Hertz measures frequency, Lux measures light intensity, and a voltmeter reads voltage rather than a standard for reporting relative changes in amplification.