When hydrogen atom is in its first excited level, its radius is [1997]

1. four times, its ground state radius

2. twice, its ground state radius

3. same as its ground state radius

4. half of its ground state radius

Subtopic:  Bohr's Model of Atom |
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The ionisation potential of helium atom is 24.6 volt, the energy required to ionise it will be

1. 24.6 eV 

2. 24.6 volt 

3. 13.6 volt 

4.13..6 eV

Subtopic:  Various Atomic Models |
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The ionization energy of 10 times ionized sodium atom is:

1. 13.6 eV 

2. 13.6×11 eV 

3. 13.611eV 

4. 13.6×(11)2 eV

Subtopic:  Bohr's Model of Atom |
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The ionisation energy of hydrogen atom is 13.6 eV, the ionisation energy of helium atom would be [1988]

1. 13.6 eV

2. 27.2 eV 

3. 6.8 eV

4. 54.4 eV

Subtopic:  Bohr's Model of Atom |
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The photon radiated from hydrogen corresponding to the second line of Lyman series is absorbed by a hydrogen-like atom X in the second excited state.   As a result the hydrogen-like atom X makes a transition to nth orbit. Then:

1. X = He+, n=4 

2. X = Li++, n = 6

3. X = He+, n=9 

4. X = Li++, n = 9

 

Subtopic:  Spectral Series |
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If an electron in an hydrogen atom jumps from an orbit ni=3 to an orbit with level nf=2, the frequency of the emitted radiation is 

1. v=36 C5 R 

2. v = CR6

3. v = 5 RC36

4. v  = 6 CR

Subtopic:  Bohr's Model of Atom |
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The wavenumber of a photon in the Brackett series of a hydrogen atom is \(\frac{9}{400}R.\) What is the quantum number of the electron that has transited from the orbit?
1. \(5\)
2. \(6\)
3. \(4\)
4. \(7\)

Subtopic:  Spectral Series |
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In an experiment to determine the e/m value for an electron using Thomson's method the electrostatic deflection plates were 0.01 m apart and had a potential difference of 200 volts applied. Then the electric field strength between the plates is 

1. 1×104 V/m 

2. 2×104 V/m

3. 4×104 V/m 

4. 5×105 V/m

Subtopic:  Various Atomic Models |
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Hydrogen \({}_{1}\mathrm{H}^{1}\), Deuterium \({}_{1}\mathrm{H}^{2}\), singly ionised helium \(\left({}_{2}\mathrm{He}^{4}\right)^+\), and doubly ionised lithium\(\left({}_{3}\mathrm{Li}^{6}\right)^{+++}\) all have one electron around the nucleus. Consider an electron transition from \(n=2\) to \(n=1\). If the wavelengths of emitted radiations are \(\lambda_1, \lambda_2, \lambda_3~\text{and}~\lambda_4\) respectively, then approximately which one of the following is correct?
1. \(4 \lambda_1=2 \lambda_2=2 \lambda_3=\lambda_4\)
2. \( \lambda_1=2 \lambda_2=2 \lambda_3=\lambda_4\)
3. \( \lambda_1=\lambda_2=4 \lambda_3=9\lambda_4\)
4. \( \lambda_1=2\lambda_2=3 \lambda_3=\lambda_4\)

Subtopic:  Bohr's Model of Atom |
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To explain his theory, Bohr used

1. conservation of linear momentum

2. conservation of angular momentum

3. conservation of quantum  frequency

4. conservation of energy

Subtopic:  Bohr's Model of Atom |
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