GUJCET 2014 Physics Solved Paper

Question : 35 of 40

Marks: +1, -0

The half life of a radio active substance is 20 days. If 2∕3 part of the substance has decayed in time t2 and 1∕3 part of it has decayed in time t1 then the time interval between t2 and t1 is (t2−t1)=