The half life of a radioactive substance is `20` minutes . The approximate time interval `(t_(1) - t_(2))` between the time `t_(2)` when `(2)/(3)` of it had decayed and time t_(1)` when `(1)/(3)` of it had decay is
A
`14 min `
B
`20 min `
C
`28 min`
D
`7 min `
Text Solution
Verified by Experts
The correct Answer is:
B
Number of undecayed atom after time `t_(1)` `(N_(0))/(3) = N_(0) e^(-lambda_(t_2))` ….(i) Number of undecayed atom after time `t_(1)` `(2N_(0))/(3) = N_(0) e^(-lambda_(t_2))` ….(ii) from (i) ` e^(-lambda_(t)_2)) = (1)/(3)` rArr - lambda t_(2) = log _(e) ((1)/(3))` ....(ii) ` from (ii) ` e^(-lambda_(t_2)) = (2)/(3)` rArr -lambda_(t_2)) ((2)/(3))` .....(iv) solving (iii) and (iv) , we get `t_(1) - t_(2) = 20 min`
SUNIL BATRA (41 YEARS IITJEE PHYSICS)|Exercise Comprehension Based Questions|2 Videos
MOVING CHARGES AND MAGNETISM
SUNIL BATRA (41 YEARS IITJEE PHYSICS)|Exercise MCQs(d )|1 Videos
Similar Questions
Explore conceptually related problems
The half-life of a radioactive substance is 20 min. The approximate time interval (t_2 – t_1) between the time t_2 when 2/3 of it had decayed and time t_1 when
Half-life of a radioactive substance is 20 min. The approximate time interval (t_2-t_1) between the time t_2 when 2/3 of it had decayed and time t_1 when 1/3 of it had decayed is
The half life of a radioactive substance is 24 days. What is the time interval (t_2-t_1) between the time t_2 " when " 2/3 of the original material had decayed and time t_1 " when " 1/3 of its original material has decayed ?
The half-life of a radioactive nucleus is 50 days. The time interval (t_2 -t_1) between the time t_2 when (2)/(3) of it has decayed and the time t_1 when (1)/(3) of it had decayed is
The half-life of a radioactive element is 100 minutes . The time interval between the stage to 50% and 87.5% decay will be:
The half life of a substance is 20 minutes. what is the time interval between 10% decay and 55% decay (approx).
" The half life of a substance is "20" minutes.What is the time interval between "33%" decay and "67" % decay? "
The half life of a radioactive substance is 20 days. If 2/3 part of the substance has decayed in time t_(2) and 1/3 part of it has decayed in time t_(1) then the time interval between t_(2) and t_(1) is (t_(2)-t_(1)) =…………….
SUNIL BATRA (41 YEARS IITJEE PHYSICS)-MODERN PHYSICS-MCQ (One Correct Answer
