Explain the different types of spectral series.

When an electron in an excited state falls back to a lower energy state, it emits photon of particular energy which is equal to the difference in energies of two states. Rydberg formula gives a relation between energy difference between various energy levels and the wavelength of the photons. ν = R Z 2 1 n 1 2 - 1 n 2 2 where R is the Rydberg constant, Z is the atomic number and n 1 and n 2 are the principal quantum numbers of the orbit. The spectral lines are formed as a result of electronic transition from one energy level to another. For a hydrogen atom, these lines are divided into five series: (i) Lyman series: Lyman series is obtained when an electron jumps to the first orbit from any other outer orbit. The wavelengths of Lyman series lies in the ultraviolet region of the spectrum. (ii) Balmer series: Balmer series is obtained when an electron jumps to the second orbit from any other outer orbit. The wavelengths of Balmer series lies in the visible region of the spectrum. (iii) Paschen series: Paschen series is obtained when an electron jumps to the third orbit from any other outer orbit. The wavelengths of Paschen series lies in the infrared region of the spectrum. (iv) Brackett series: Brackett series is obtained when an electron jumps to the fourth orbit from any other outer orbit. The wavelengths of Brackett series lies in the infrared region of the spectrum. (v) Pfund series: This series is obtained when an electron jumps to the fifth orbit from any other outer orbit. The wavelengths of Pfund series lies in the infrared region of the spectrum.

E M B I B E

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 13 - Atom, Origin of Spectra : Bohr's Theory of Hydrogen Atom>Exercise>Q 7

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Earn 100

Velocity of electron in Bohr's first orbit of hydrogen atom is in order of

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Important Questions on Atom, Origin of Spectra : Bohr's Theory of Hydrogen Atom

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 13 - Atom, Origin of Spectra : Bohr's Theory of Hydrogen Atom>Exercise>Q 8

An alpha nucleus of energy

\frac{1}{2} m v^{2}

bombards a heavy nuclear target of charge

Z e

. Then the distance of closest approach for the alpha nucleus will be proportional to

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 13 - Atom, Origin of Spectra : Bohr's Theory of Hydrogen Atom>Exercise>Q 9

Explain the J.J. Thomson experiment to determine the specific charge of electron.

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 13 - Atom, Origin of Spectra : Bohr's Theory of Hydrogen Atom>Exercise>Q 10

Write the shortcomings of Thomson's atomic model.

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 13 - Atom, Origin of Spectra : Bohr's Theory of Hydrogen Atom>Exercise>Q 11

Answer the following question, which helps you understand the difference between Thomson’s model and Rutherford’s model better.

In which model is it completely wrong to ignore multiple scattering for the calculation of average angle of scattering of $α -$ particles by a thin foil?

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 13 - Atom, Origin of Spectra : Bohr's Theory of Hydrogen Atom>Exercise>Q 12

Suppose you are given a chance to repeat the alpha-particle scattering experiment using a thin sheet of solid hydrogen in place of the gold foil. (Hydrogen is a solid at temperatures below