Atoms And Nuclei Question 332
Question: Atomic weight of boron is 10.81 and it has two isotopes $ _{5}B^{10} $ and $ _{5}B^{11} $ . Then ratio of $ _{5}B^{10}: _{5}B^{11} $ in nature would be
Options:
A) 19 : 81
B) 10 : 11
C) 15 : 16
D) 81 : 19
Show Answer
Answer:
Correct Answer: A
Solution:
- Let the percentage of $ B^{10} $ atoms be x, then average atomic weight $ =\frac{10x+11(100-x)}{100}=10.81\Rightarrow x=19 $
$ \therefore ,\frac{{N_{B^{10}}}}{{N_{B^{11}}}}=\frac{19}{81} $
