SSC Selection Post 2019 PYQ — Question 31

The correct answer is option 3 i.e. Decibel.

 

The SI unit for measuring noise (sound level) is the decibel (dB). Decibel is a logarithmic derived unit used to express the ratio of sound pressure or intensity relative to a reference level.While pascal (Pa) is the SI unit for sound pressure and watt per square meter (W/m²) is used for sound intensity, decibel is conventionally used to quantify noise levels due to its alignment with human hearing perception .

The other options—ampere, kelvin, and candela—are SI base units for electric current, temperature, and luminous intensity respectively, and aren’t used to measure noise.