Geologists use the decay of potassium-40 in volcanic rocks to determine their age. Potassium-40 has a half-life of 1.26 109 years, so it can be used to date very old rocks. If a sample of rock 3.15 108 years old contains 2.73 10-7 g of potassium-40 today, how much potassium-40 was originally present in the rock

Explanation:

The mass of radioactive isotope at a certain time is given by the following expression:

Time constant can be calculed in terms of half-life:

The initial mass is:

the energy to form plasma comes from heat or electricity in the atmosphere!

sunny~ ☺

the child will have heterozygous dominant chromosomes as characters of his father are dominant over the characters of his mother.

the child is heterozygous