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.Management Sciences
Category: Atomic Spectra
The characteristic X-rays spectrum is due to_____________?
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
In hydrogen spectrum which one of the following series lies in the ultraviolet region ?
A. Balmer series
B. Pfund series
C. Bracket series
D. Lymann series
The metastable state for an atom in laser light is_____________?
A. 10-4 sec
B. 10-5 sec
C. 10-3 sec
D. 10-8 sec
X-rays are diffracted by a crystal but not by a diffraction grating because_____________?
A. The ions in a crystal are well arranged
B. The lines in a diffraction grating cannot reflect X-rays.
C. The penetration power of X-rays is high in a diffraction grating
D. The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal
Hydrogen atom does not emit X-rays because _________________?
A. its energy levels are too close to each other
B. its energy levels are too far apart
C. it is too small in size
D. it has a single electron
When we excite some atoms by heat collision or electrical discharge they will________________?
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
In an electronic transition atom cannot emit______________?
A. γ-rays
B. Infra red radiation
C. Visible light
D. Ultraviolet rays
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