Modern Physics 3 Question 6

6. Half-lives of two radioactive elements A and B are 20min and 40min, respectively. Initially, the samples have equal number of nuclei. After 80min, the ratio of decayed numbers of A and B nuclei will be

(2016 Main)

(a) 1:16

(b) 4:1

(c) 1:4

(d) 5:4

Show Answer

Solution:

  1. A : Numbers left : NN2N4N8N16

Number decayed, NA=NN16=1516N

B : Numbers left : NN2N4 Numbers decayed, NB=NN4=34N

Ratio :

NANB=(15/16)N(3/4)N=54



जेईई के लिए मॉक टेस्ट

एनसीईआरटी अध्याय वीडियो समाधान

दोहरा फलक