N= m/v n=0.077/.200 = 0.385
The answer is (4). You may recall the term "radiometric dating," which refers to the dating of old artifacts by measuring proportions of certain radioactive isotopes they contain and making calculations based on their estimated half-lives. Geological formations are dated in this way.
It was a Cambridge UK scientist in the early part of the 20 th century who discovered the electron. His name was J J Thompson.
T=2T
m=10 g
m=m₀2^(-t/T)
m₀=m/{2^(-2T/T)=m/2⁻²
m₀=10/2⁻²=40 g
40 grams
.150 = 3
20.20 = 4
25.00 = 4
If a 0 does not have a number or a period after it, it is not significant.
If the 0 is behind the decimal point, it is always significant.
