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Logarithmic Reduction to Percent?
I'm having a brain fart about logarithms. I'm reading an article which claims 5.5log10 reduction is complete inactivation of viruses. This to me means it's 99.99999 percent of viruses eliminated.
Yet log(5.5) in a calculator gives 0.74, I take as 74 percent viruses eliminated.
What am I doing wrong?
1 Answer
- AmyLv 75 years agoFavorite Answer
log(5.5) means "10 to what power equals 5.5?"
"5.5 log reduction" means "divide by 10^5.5."
Your other error is thinking that 10^-5 and (10^-5)% are the same thing. 10^0 is 100%. 10^-5 is (100/10^5)%
99.9997% of the viruses were eliminated.
And if the body cannot support more than 10^5 virus particles, then reducing the viral load by that factor results in less than one virus particle.