In laser production the state in which more atoms are in the upper state than in the lower one is called_____________?

Related Mcqs:

1. 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

2. In He-Ne laser the lasing action is produced by_______________?

   A. Ne only
   B. He-Ne both
   C. Electrons of He
   D. Electrons Ne

3. Reflecting mirrors in laser is used to______________?

   A. Further stimulation
   B. Lasing more
   C. For producing more energetic lasers
   D. All

4. 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

5. Excited atoms return to their ground state in_______________?

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

6. 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

7. Materials in which valence electrons are tightly bound to their atoms at low temperature are called___________________?

   A. Semi conductor
   B. Super conductors
   C. Insulators
   D. Conductor

8. Semi-conductors with donor atoms and free electrons belong to the type________________?

   A. n
   B. p
   C. mix
   D. any of above

9. To obtain an n-type semiconductor germanium crystal it must be doped with foreign atoms whose valency is_____________?

   A. 2
   B. 3
   C. 4
   D. 5

10. To obtain a p-type semi-conductor Si Crystal must be doped with foreign atoms whose valency is_____________?

    A. 2
    B. 3
    C. 4
    D. 5