Choose the correct statement
1
The carbon 14 has a half life of 5700 year. The ratio of C14 atoms to the total number of carbon atoms in the atmosphere is 12186 x 10⁻⁴ years
2
The number of nuclei in a radioactive substance 320 at t = 20. After 4 half lives, the number of nuclei left undecayed is 40.
3
Ch14 has a half life of 5700 years. The ratio of the number of Ch14 atoms to the total number of carbon atoms in the atmosphere is 12186 x 10⁻⁴.
4
C14 has a half life of 5700 years. The ratio of the number of C14 atoms to the total number of carbon atoms in the atmosphere is 12186 x 10⁻⁴.