A hydrogen atom, initially in the ground state is excited by absorbing a photon of wavelength 980 Å. The radius of the atom in the excited state, in terms of Bohr radius a0 will be: (hc = 12500 eV Å) (a) 4a0 (b) 9a0 (c) 25a0 (d) 16a0

Answer: (d). Photon energy = (12500)/(980) ≈ 12.75 eV. En = -13.6 + 12.75 = -0.85 eV ⇒ n = 4. rn = n² a₀ = 16 a₀ So the answer is (d) 16a₀.

A hydrogen atom, initially in the ground state is excited by… | JEE Main 2019 (11 Jan, Shift 1)

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Transitions, Photon Emission & Excitation

${}$ A hydrogen atom, initially in the ground state is excited by absorbing a photon of wavelength 980 $\text{Å}$ . The radius of the atom in the excited state, in terms of Bohr radius a0 will be: (hc = 12500 eV $\text{Å}$ )

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Answer: (d)

Photon energy $= \frac{12500}{980} \approx 12.75$ eV.
$E_n = -13.6 + 12.75 = -0.85$ eV $\Rightarrow n = 4$ .
$r_n = n^2 a_0 = 16 a_0$
So the answer is (d) $16a_0$ .

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