Free Atomic Spectra MCQs with Answers

• A. Infrared region
• B. Ultraviolet region
• C. X-ray region
• D. Visible region

Explanation: Balmer transitions all end on the second energy level, and those energy gaps correspond to visible photons, which is why these are the…

• A. Lyman series is a continuous spectrum.
• B. Paschen series is a line spectrum in the infra red.
• C. Balmer series is a line spectrum in the ultraviolet.
• D. the spectral series formula can be derived from the Rutherford model of the hydrogen atom.

Explanation: The Paschen series consists of transitions ending at the n = 3 energy level, and its wavelengths lie in the infrared region.

• A. Electrons
• B. Protons
• C. Neutrons
• D. Neutrino

Explanation: Rutherford's model could not explain why orbiting electrons do not continuously lose energy and spiral into the nucleus, nor why atoms…

• A. The illumination of the target metal by ultra-violet radiation
• B. The bombardment of the target by protons
• C. The bombardment of target by electrons
• D. The absorption of radiation by the target metal

Explanation: Characteristic X-rays arise when incident electrons eject inner-shell electrons from target atoms and electrons from higher shells fall…

• A. γ-rays
• B. Infra red radiation
• C. Visible light
• D. Ultraviolet rays

Explanation: Electronic transitions involve changes in atomic electron energy levels and usually produce infrared, visible or ultraviolet photons.

• A. ultraviolet rays
• B. X-rays
• C. infra red radiation
• D. visible radiation

Explanation: Red light has the longest wavelength in the visible spectrum, so radiation with an even longer wavelength lies in the infrared region.

• A. 4th orbit
• B. 5th orbit
• C. 3rd orbit
• D. 2nd orbit

Explanation: The Brackett series contains hydrogen transitions that terminate at the fourth energy level, n = 4.

• A. continuous spectra for atoms
• B. discrete spectra for atoms
• C. either continuous nor discrete
• D. no spectrum

Explanation: According to Rutherford's classical model, orbiting electrons should continuously radiate energy, producing a continuous spectrum as their…

• A. radiate electromagnetic energy with a continuous distribution of wavelength
• B. absorb particular wavelengths when white light is incident on them
• C. radiate electromagnetic energy of discrete characteristic wavelength
• D. emit either invisible or visible light

Explanation: Excited atoms return to lower energy levels by emitting photons whose energies equal the differences between allowed levels.

• A. 1st to 5th orbit
• B. 2nd to 5th orbit
• C. 3rd to 5th orbit
• D. 4th to 5th orbit

Explanation: For absorption into the fifth orbit, the absorbed photon energy is the difference between the fifth-level energy and the starting-level…

• A. band spectrum
• B. line spectrum
• C. continuous spectrum
• D. absorption spectrum

Explanation: Hydrogen atoms have quantized energy levels, so emitted photons have only specific energies and wavelengths.

• A. three
• B. four
• C. five
• D. six

Explanation: The principal hydrogen spectral series are Lyman, Balmer, Paschen, Brackett and Pfund.

• A. 10-10s
• B. 10-8s
• C. 10-6s
• D. 10-9s

Explanation: An excited atomic state usually has a lifetime of about 10^-8 s before spontaneous emission returns the atom to a lower state.

• A. Balmer series
• B. Pfund series
• C. Bracket series
• D. Lymann series

Explanation: The Lyman series consists of transitions ending at n = 1. These transitions have relatively large energy differences and therefore high…

• A. Simple vibratory motion
• B. Standing wave motion
• C. Vibratory motion like up and down
• D. S.H.M likes the sound

Explanation: In the de Broglie model, an electron allowed in an atomic orbit behaves like a standing matter wave, with the orbit containing an integral…

• A. J.J.Thomson model
• B. Rutherfords model
• C. Bohrs model
• D. All of the above laws contradict the statement

Explanation: In Thomson's model, the atom was considered a diffuse sphere of positive charge with electrons embedded in it, so its positive charge and…

• A. Absorption
• B. Emission
• C. Release
• D. Free particle

Explanation: A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from the emission or absorption of…

• A. Electric fibre
• B. Neon Street sign
• C. Red traffic light
• D. Sun

Explanation: Neon lighting consists of brightly glowing, electrified glass tubes or bulbs that contain rarefied neon or other gases.

• A. Greater
• B. Greater than equal to
• C. Less
• D. None of these

Explanation: Atomic spectra are produced when the atoms of an element in a gaseous state are excited to a higher energy level, and then they emit…

• A. Ar filled
• B. He filled
• C. H filled
• D. Vaccum

Explanation: An X-ray tube is a vacuum tube that is designed to generate X-rays by accelerating electrons to high speeds and then colliding them with a…