A. 10-4 sec
B. 10-5 sec
C. 10-3 sec
D. 10-8 sec
Related Mcqs:
- The velocity of laser light is___________________?
A. Less than ordinary light
B. More than ordinary light
C. Equal to ordinary light
D. Different for different colours or frequency - In laser production the state in which more atoms are in the upper state than in the lower one is called_____________?
A. Metal stable state
B. Normal state
C. Inverted population
D. All the above - 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 - In He-Ne laser the lasing action is produced by_______________?
A. Ne only
B. He-Ne both
C. Electrons of He
D. Electrons Ne - Reflecting mirrors in laser is used to______________?
A. Further stimulation
B. Lasing more
C. For producing more energetic lasers
D. All - In a photoelectric effect monochromatic light is incident on a metal surface. If the incident light of twice the intensity but of same wavelength the kinetic energy of the emitted electron_______________?
A. Becomes double
B. Remains same
C. Becomes half
D. First increases then decrease because of the curvilinear graph - Ratio of the weight of H-atom to that of an electron is approximately______________?
A. 18.336
B. 1836
C. 18360
D. 183.6 - 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 - In an electronic transition atom cannot emit______________?
A. γ-rays
B. Infra red radiation
C. Visible light
D. Ultraviolet rays - The diameter of an atom is approximately_______________?
A. 10-12m
B. 10-11m
C. 10-10m
D. 10-14m
