A. three
B. four
C. five
D. six
Related Mcqs:
- 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 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 - Maximum frequency in the spectrum from X-ray tube is directly proportional to the______________?
A. Number of incident electron i.e. filament current
B. The kinetic energy of the incident electron i.e. the potential difference through which they are accelerated
C. The soft target which can easily emit electrons
D. All of above are correct - What is wavelength of visible spectrum?
A. 8500 – 9800 angstrom
B. 7800 – 8000 angstrom
C. 3900 – 7600 angstrom
D. 1300 – 3000 angstromSubmitted by: Engr Allah Wadhayo
- 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 - The radiations emitted form hydrogen filled discharge tube show____________?
A. band spectrum
B. line spectrum
C. continuous spectrum
D. absorption spectrum - The speed of sound in hydrogen is _____________ time than that in oxygen?
A. Two times
B. Three times
C. Four time
D. Six time - During fusion of hydrogen into helium________________?
A. Energy is absorbed
B. Energy is released
C. Mass is increased due to energy absorption
D. Mass is reduced due to the energy released - Bracket series is obtained when all transition of electron terminate on_______________?
A. 4th orbit
B. 5th orbit
C. 3rd orbit
D. 2nd orbit - Ground state energy of the 4th orbit in a H-atom is_____________?
A. 13.60 eV
B. 3.40 eV
C. 0.85 eV
D. 1.51 eV
