Statement-1 : Boron has relative atomic mass 10.81.
Statement-2 : Boron has two isotopes `._5^10B` and `._5^11B` and their relative abundance is `19%` and `81%`.

Assertion : Relative atomic mass of boron is 10.8 Reason : Boron has two isotopes B-10 and B-11 with percentage abundance of 19.6 % and 80.4 % respectively.

In each of the following two questions two statements are given one labelled as the Assertion(A) or Statement I and the other labelled as the reason (R) or statement II. Examine these statements carefully and mark the correct choice as per following instructions Assertion (A) - Relative atomic mass of boron is 10.8 Reason (R) - Boron has two isotopes B-10 and B-11 with percentage abundance of 19.6% and 80.4% respectively.

B has two isotopes 10B (19%) and 11B( 81%) . What is the atomic mass of B .

The natural boron of atomic weight 10.81 is found to have two isotopes .^10B and .^11B .The ratio of abundance of isotopes of natural boron should be

The natural boron of atomic weight 10.81 is found to have two isotopes .^10B and .^11B .The ratio of abundance of isotopes of natural boron should be

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 in nature would be.