(a) लीथियम के दो स्थायी समस्थानिकों `._(3)^(6)Li` एवं `._(3)^(7)Li` की बहुलता का प्रतिशत क्रमशः 7.5 एवं 92.5 हैं। इन समस्थानिको के द्रव्यमान क्रमशः 6.0512u एवं 7.01600u हैं। लीथियम का परमाणु द्रव्यमान ज्ञात कीजिए।
(b) बोरॉन के दो स्थायी समस्थानिक `._(5)^(10)B` एवं `._(5)^(11)B` है। उनके द्रव्यमान क्रमशः `10.01294u` एवं `11.00931u` एवं बोरॉन का परमाणु भार `10.811u` है। `._(5)^(10)B` एवं `._(B)^(11)B` की बहुलता ज्ञात कीजिए।

Broron has two stable isotopes, ._(5)^(10)B and ._(5)^(11)B . Their respective masses are 10.01294 u and 11.00931 u, and the atomic mass of boron is 10.811 u. Find the abundances of ._(5)^(10)B and ._(5)^(11)B .

(a) Two stable isotopes of lithium ""_(3)^(6)Li and ""_(3)^(7)Li have respective abundances of 7.5% and 92.5%. These isotopes have masses 6.01512 u and 7.01600 u, respectively. Find the atomic mass of lithium. (b) Boron has two stable isotopes, ""_(5)^(10)B and ""_(5)^(11)B . Their respective masses are 10.01294 u and 11.00931 u, and the atomic mass of boron is 10.811 u . Find the abundances of ""_(5)^(10)B and ""_(5)^(11)B .

(a) Two stable isotopes of lithium ""_(3)^(6)Li and ""_(3)^(7)Li have respective abundances of 7.5% and 92.5%. These isotopes have masses 6.01512 u and 7.01600 u, respectively. Find the atomic mass of lithium. (b) Boron has two stable isotopes, ""_(5)^(10)B and ""_(5)^(11)B . Their respective masses are 10.01294 u and 11.00931 u, and the atomic mass of boron is 10.811 u . Find the abundances of ""_(5)^(10)B and ""_(5)^(11)B .

Boron has two stable isotopes, "_5^10B and "_5^11B . Their respective masses are 10.01294 u and 11.00931 u, and the atomic mass of boron is 10.811 u. Find the abundances of "_5^10B and "_5^11B .