Question

The energy required to excite an electron in hydrogen atom to its first excited state is, the frequency of emitted photon due to the given transition is
$\left(h = 6.64 \times 10^{-34} \,Js, 1\, eV = 1.6 \times 10^{-19 } J\right)$

• A. $2.46 \times 10^{10}Hz$
• B. $2.46 \times 10^{12}Hz$
• C. $2.46 \times 10^{15}Hz$
• D. $2.46 \times 10^{18}Hz$

Answer 1

Answer: (C)

From Bohr’s third postulate of atomic theory the frequency of emitted photon
$h\upsilon = E_{2} - E_{1} = 10.2\, eV $
$\therefore \upsilon = \frac{10.2}{h}eV $
Here,$ 10.2 \,ev = 10.2\times 1.6 \times 10^{-19} \,J$,
$ h =6.64 \times 10^{-34} J s$
$\therefore \upsilon= \frac{10.2\times 1.6\times 10^{-19}}{6.64\times 10^{-34}} $
$ = 2.46 \times 10^{15} Hz$