Question

The number of atoms in a radioactive sample reduces from 1000 to 100 in two days. Then the number of atoms remaining at the end of four days is

• A. 25
• B. 20
• C. 10
• D. 50

Answer 1

Answer: (C)

10

Answer 2

${1000 ->[2d] 100 ->[2d] \frac{100}{10}}$ After 4 days 10 atoms will remain.