Semi-conductor germanium and silicon are:
A. pentavalent
B. trivalent
C. divalent
D. tetravalent
Electrons present in p-type material due to thermal pair generation are:
A. majority carriers
B. minority carriers
C. dual carriers
D. blockers
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
Reflecting mirrors in laser is used to:
A. Further stimulation
B. Lasing more
C. For producing more energetic lasers
D. All
In He-Ne laser the lasing action is produced by:
A. Ne only
B. He-Ne both
C. Electrons of He
D. Electrons Ne
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
UV radiation can be produced by:
A. Heating the filament
B. Electron excitation in the gas
C. Ionization of atoms
D. All the above
Radiation produced from TV picture tube is:
A. B-rays
B. X-rays
C. Far infrared
D. Infrared
X-rays are similar in nature to:
A. Cathode rays
B. Positive rays
C. γ-rays
D. Beta rays
In an electronic transition atom cannot emit:
A. γ-rays
B. Infra red radiation
C. Visible light
D. Ultraviolet rays
