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JEE Main Physics Class 12 Atoms and Nuclei Part 1 Questions
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© examsnet.com
Question : 9
Total: 100
A hydrogen atom, initially in the ground state is excited by absorbing a photon of wavelength 980Å. The radius of the atom in the excited state, in terms of Bohr radius
a
0
,will be:
[11 April 2019 I]
25
a
0
9
a
0
16
a
0
4
a
0
Validate
Solution:
Energy of photon
=
h
c
λ
=
12500
980
=
12.75
e
V
Energy of electron in
n
th
orbit is given by
E
n
=
−
13.6
n
2
⇒
E
n
−
E
1
=
−
13.6
[
1
n
2
−
1
1
2
]
⇒
12.75
=
13.6
[
1
1
2
−
1
n
2
]
⇒
n
=
4
∴
Electron will excite to
n
=
4
We know that '
R
′
∝
n
2
∴
Radius of atom will be
16
a
0
© examsnet.com
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