# Ionisation potential of hydrogen atom is 13.6 eV. Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12.1 eV. According to Bohr's theory, the spectral lines emitted by hydrogen will be: 1. two  2. three 3. four  4. one

Subtopic:  Spectral Series |
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The frequency of the series limit of the Balmer series of hydrogen atoms in terms of Rydberg constant $$R$$ and velocity of light $$C$$ is:
1. $$\frac{RC}{4}$$
2. $$RC$$
3. $$\frac{4}{RC}$$
4. $$4RC$$

Subtopic:  Spectral Series |
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Orbital acceleration of electrons is:
1. $$\frac{n^2h^2}{4\pi^2m^2r^3}$$
2. $$\frac{n^2h^2}{4n^2r^3}$$
3. $$\frac{4n^2h^2}{\pi^2m^2r^3}$$
4. $$\frac{4n^2h^2}{4\pi^2m^2r^3}$$

Subtopic:  Bohr's Model of Atom |
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Consider the spectral line resulting from transition $$n=2$$ to $$n = 1$$ in the atoms and ions given below.  The shortest wavelength is given by:

 1 hydrogen atom 2 deuterium 3 singly ionised helium 4 doubly ionised lithium
Subtopic:  Spectral Series |
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An $\alpha -$particle of energy 5 MeV is scattered through $180°$ by a fixed uranium nucleus. The distance of closest approach is of the order

1.

2.

3.

4.

Subtopic:  Various Atomic Models |
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Out of the following which one is not a possible energy for a photon to be emitted by hydrogen atom according to Bohr's atomic model:

1. 13.6 eV

2. 0.65 eV

3. 1.9 eV

4. 11.1 eV

Subtopic:  Bohr's Model of Atom |
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The energy of an electron in an excited hydrogen atom is $$-3.4~\text{eV}$$.  Its angular momentum will be:
($$h = 6.626\times 10^{-34}$$ J-s)
1. $$1.11\times 10^{34}~\text{J-s}$$
2. $$1.51\times 10^{-31}~\text{J-s}$$
3. $$2.11\times 10^{-34}~\text{J-s}$$
4. $$3.72\times 10^{-34}~\text{J-s}$$

Subtopic:  Bohr's Model of Atom |
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As per the Bohr model, the minimum energy (in eV) required to remove the electron from the ground state of a double ionised lithium ion ($$Z=3$$) is:
1. $$1.51$$
2. $$13.6$$
3. $$40.8$$
4. $$122.4$$

Subtopic:  Bohr's Model of Atom |
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The wavelength of Ka X-rays produced by an X-ray tube is 0.76 $\stackrel{\circ }{A}$. Find the atomic number of the anode material of the tube?

1. 41

2. 30

3. 20

4. 10

Subtopic:  X-Ray (OLD NCERT) |
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According to Bohr's theory, the moment of momentum of an electron revolving in second orbit of hydrogen atom will be:
1. $$2\pi h$$
2. $$\pi h$$
3. $$\frac{h}{\pi}$$
4. $$\frac{2h}{\pi}$$

Subtopic:  Bohr's Model of Atom |
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