A radioactive element has half-life period `800 yr`. After `6400 yr`, what amount will remain?

A radioactive element has half life period 800 years. After 6400 years what amount will remain?

A radioactive element has half-life period 1600 years. After 6400. years what amount will remain ?

A radioactive element has a half life of one day. After three days, the amount of element left will be:

A radioactive element has a half life of one day. After three days the amount of the element left will be :