The five types of white cells and the approximate percentage they make up in the blood are: 1  Neutrophils (55% to 70%) 2  Band neutrophils (0% to 3%) 3  Lymphocytes (20% to 40%) 4  Monocytes (2% to 8%) 5  Eosinophils (1% to 4%) 6  Basophils (0.5% to 1%)
A sound level meter is an instrument that can measure sound level, commonly used in noise pollution studies for the quantification of different kinds of noise, especially for industrial, environmental and aircraft noise. common variant of the sound level meter is a noise dosemeter (dosimeter in American English). However, this is now formally known as a personal sound exposure meter (PSEM) and has its own International standard IEC 61252:1993.
The number of cycles per second (Hertz) (abbreviated as, hz) of anything that oscillates is called the frequency. The electricity of an AC wall outlet is said to have a frequency of 60 Hertz as it cycles negative then positive 60 times each second. Sound is an oscillating wave, but it has a broad range of frequencies. A low frequency sound (say, 50 hz) might sound like a low rumble, while a high frequency sound (say 12,000 hz), might sound more like a sizzle. A person with normal hearing can hear all the way up to about 20,000 hz.