Atomic weight of boron is 10.81 and it has two isotopes ₅¹⁰B and ₅¹¹B. Then, the ratio of atoms of ₅¹⁰B and ₅¹¹B in nature would be (a) 19: 81 (b) 10: 11 (c) 15: 16 (d) 81: 19

Answer: (a). Let fraction of ¹⁰B be x: 10x + 11(1 - x) = 10.81. 11 - x = 10.81 ⇒ x = 0.19 Ratio = 0.19: 0.81 = 19: 81 So the answer is (a) 19: 81.

Atomic weight of boron is 10.81 and it has two isotopes ₅¹⁰B and… | NEET 1998 (AIPMT)

Q38NEET 1998 · AIPMTMedium

Nucleus: Composition, Size & Nuclear Force

Atomic weight of boron is $10.81$ and it has two isotopes ${}_{5}^{10}\text{B}$ and ${}_{5}^{11}\text{B}$ . Then, the ratio of atoms of ${}_{5}^{10}\text{B}$ and ${}_{5}^{11}\text{B}$ in nature would be

Show answer and solution

Answer: (a)

Let fraction of ${}^{10}\text{B}$ be $x$ : $10x + 11(1 - x) = 10.81$ .
$11 - x = 10.81 \Rightarrow x = 0.19$
Ratio $= 0.19 : 0.81 = 19 : 81$
So the answer is (a) $19 : 81$ .

Report a mistake

Nucleus: Composition, Size & Nuclear Force question from NEET 1998 (AIPMT)

More questions on Nucleus: Composition, Size & Nuclear Force