The number of electrons in the valence shell of calcium is 

1. 6

2. 8

3. 2

4. 4

Subtopic:  Number of Electron, Proton & Neutron |
 83%
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The brackett series of spectral lines arise when an electron in an excited hydrogen atom jumps from an energy level

1. n=5 to n=1

2. n=5 to n=3

3. n=5 to n=4

4. n=5 to n=2

Subtopic:  Hydrogen Spectra |
 77%
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What is the ratio of the time period of revolution of electron He+ ion sample in the orbit where the path length is three time the de-broglies wavelength to the time period of revolution in the ground state –

1. 27:1

2. 1:27

3. 9:8

4. 8:9

Subtopic:  De Broglie Equation |
 56%
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The ratio of the wavelengths of the last lines of the Balmer and Lyman series is:

1. 4:1

2. 27:5

3. 3:1

4. 9:4

Subtopic:  Type of Spectra |
 73%
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The energy of the emitted photon when an electron in Be3+ ion returns from n=2 level to the ground state is 

1. 2.616 x 10-17J

2. 26.16 x 10-17J

3. 261.6 x 10-18J

4. 2616 x 10-17J

Subtopic:  Bohr's Theory |
 62%
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The accelerating potential to be imparted to a beam of electrons to give an effective wavelength of 2.42 nm is 

1. 2.56V

2. 3.42V

3. 0.256V

4. 0.342V

Subtopic:  Electromagnetic Radiation |
 53%
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The splitting of spectral lines in a magnetic field, arising out of the orbital motion of electrons only and the further splitting due to spin motion are respectively called

1. Zeeman and Stark effects

2. Zeeman and anomalous Zeeman effects

3. Stark and Zeeman effects

4. Zeeman and Kerr effects

Subtopic:  Type of Spectra |
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A photon of wavelength 300 nm causes the emission of two photons. If the wavelength of one of them is 700 nm. What is the wavelength of the other photon?

1. 525 nm

2. 600 nm

3. 450 nm

4. 300 nm

Subtopic:  Electromagnetic Radiation |
 67%
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The electronic transition in the hydrogen atom that emits maximum energy is:

1. 2  1

2. 1  4

3. 4  3

4. 3  2

Subtopic:  Hydrogen Spectra |
 66%
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The spectrum of He-atom may be considered similar to the spectrum of - 

1. H

2. Li+

3. Na

4. He+

Subtopic:  Hydrogen Spectra |
 75%
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