Radio activity is an accidental discovery by Henry Becqueral.
A certain radio active element has a half life of 10 days. How long it will take for 75% of its atoms originally present to disintegrate?

Half life of a radioactive element is 16 hrs. What time will it take for 75% disintegration ?

D D T an exposure to water decomposes. Half life = 10 years. How much time will it take for its 99% decomposition?50 years, 66.5 years, 500 years, 700 years

After 1 hour, 1/8 of the initial mass of a certain radio active isotope remains undecayed. The half-life of the isotope is

Suppose you are a health physicist and you are being consulted about a spill occurred in a radio chemistry lab. The isotope spilled out in the lab was 500 micro cure of 131 Ba which has half life of 12 days. Your recommendation is to clear the lab until the radiation level is down to 1 micro curie. How length will the lab have to be closed.

A radioactive element gets spilled over the floor of a room, Its half-life period is 30 days. If the initial activity is 10 times the permissible value, after how many days will it be safe to enter the room ?

A radioactive sample had an initial activity of 28 disintegrations per minute. 30 minutes later, its activity became 14 disintegrations per minute. How many atoms of the radioactive nuclide were present intially ?