10g of a radioactive substance is reduce...

10g of a radioactive substance is reduced to 1.25 g after 15 days. Its 1kg mass will reduce to 500g in

A

500 days

B

125 days

C

25 days

D

5 days

Verified by Experts

The correct Answer is:

D

`N = [1/2]^n xx N_0`
`1.25 = [1/2]^n xx 10`
`[1/2]^n = (1.25)/(10) implies 1/8 = [1/2]^3 , n=3`
Half -life time `=(15)/(3) = 5 `days

Similar Questions

Explore conceptually related problems

8 grams of a radioactive substance is reduced to 0.5 g after 1 hour . The t_(1//2) of the radioactive substance is

16 g of a radio active substance is reduced to 0.5 g after 1 hour. The half life of the radioactive substance in minutes is

Ceratain radioactive substance reduces to 25% of its value is 16 days . Its half-life is

10 g of a radioactive isotope is reduced to 1.25 g in 12 years. Therefore half-life period of the isotope is

The t_(0*5) of a radioactive substance is 100 days. After 400 days , one gram of element will be reduced to