Question

If the energy of a hydrogen atom in nth orbit is $\Rightarrow$ then energy in the nth orbit of a singly ionized helium atom will be

• A. $s=\frac{\frac{1}{2}\times m\times {(10)}^2}{\mu mg}$
• B. $=\frac{50}{0.5\times 10}=10m.$
• C. $F=\mu R$
• D. $R=w=250N.$

Answer 1

Answer: (C)

Key Idea: Atomic number of helium is twice that of hydrogen. When e, m are the charge and mass of electron in the nth orbit, h is Plancks constant and Z is the atomic number, then the energy of the electron in the electron in the nth orbit is $E=-\frac{M{Z}^2{e}^4}{8{\epsilon }_o{h}^2}.\frac{1}{n^2}$ Given, $Z_H=1,Z_{He}=2$ $\therefore$ $\frac{E_H}{E_{He}}=\frac{Z_H^2}{Z_{He}^2}=\frac{1}{4}$ $\Rightarrow$ $E_{He}=4E_H$ Given, $E_H=E_n$ $E_{He}=4E_n$