A radioactive substance has 10^8 nuclei Its half life is 30s The no, of nuclei left after 15s - Physics - Nuclei

Question

A radioactive substance has 10^8 nuclei Its half life is 30s The
no, of nuclei left after 15s is nearly
1-2x10^5
2-3x10^6
3-7x10^7
4-5x10^8

Komal Jain · Accepted Answer

The initial number of nuclei, N0 =108
Half life of the radioactive substance, t1/2
= 30 s
Therefore,
N=N0e-λt=N0e-ln2×tt1/2=N0eln2tt1/2=N02tt1/2⇒N=10821530=108212=1082=7
07×107Therefore, the correct option is option 3

A radioactive substance has 10^8 nuclei. Its half life is 30s. The no, of nuclei left after 15s is nearly 1-2x10^5 2-3x10^6 3-7x10^7 4-5x10^8

A radioactive substance has 10^8 nuclei. Its half life is 30s. The no, of nuclei left after 15s is nearly

1-2x10^5

2-3x10^6

3-7x10^7

4-5x10^8