If a radioactive material has half life of one year, a sample will be reduced to 1/8 of its mass in

4 gram of a radioactive material of half life 10 years is kept for 15 years. How much of the material will disintegrate?

4g of a radioactive material of half life 10 years is kept in a store for 15 years. How much material is disntegrated ?

The half-life of a radioactive element is 1580 years. How long will it take to reduce to 1/4th of its original mass ?

A radioactive sample has half life of 1500 years. A sealed tube containing 1 g of sample will be containing …… of the sample after 3000 years. The missing figure is