During the nuclear explosion, one of the products is ⁹⁰Sr with half life of 6.93 years. If 1 $$\mu $$ g of ⁹⁰Sr was absorbed in the bones of newly born baby in placed of Ca, how much time, in years, is required to reduce much time, in year, is required to reduce it by 90% if it not lost metabolically.

The number of orbitals associated with quantum number n = 5, m_s = +$${1 \over 2}$$ is :

What is the product of following reaction ?

Consider the following reaction :


The product 'X' is used :