Atoms - Result Question 25

26. The ionization energy of the electron in the hydrogen atom in its ground state is $13.6 eV$. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between

[2009]

(a) $n=3$ to $n=1$ states

(b) $n=2$ to $n=1$ states

(c) $n=4$ to $n=3$ states

(d) $n=3$ to $n=2$ states

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Answer:

Correct Answer: 26. (c)

Solution:

(c) $\frac{n(n-1)}{2}=6$

$\square$ $\square$

$n^{2}-n-12=0$

$(n-4)(n+3)=0$ or $n=4$

If electron falls from orbit $n_2$ to $n_1$ then the number of spectral lines emitted is given by $N_E=\frac{(n_2-n_1+1)(n_2-n_1)}{2}$

If an electron falls from $n$th orbit to ground state $(n=1)$ then number of spectral lines emitted, $N_E=\frac{n(n-1)}{2}$