291. Reflecting mirrors in laser is used to______________?
A. Further stimulation
B. Lasing more
C. For producing more energetic lasers
D. All

292. 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

293. Electrons present in p-type material due to thermal pair generation are_____________?
A. majority carriers
B. minority carriers
C. dual carriers
D. blockers

294. Semi-conductor germanium and silicon are_________________?
A. pentavalent
B. trivalent
C. divalent
D. tetravalent

295. p-n junction when reversed biased acts as a_______________?
A. capacitor
B. inductor
C. on switch
D. off switch

296. In n-p-n transistor, p works as______________?
A. collector
B. emitter
C. base
D. any of above

297. Identify the correct statement about minority carriers_____________?
A. holes in n-type and free electrons in p-type
B. holes in n-type and p-type
C. free electrons in n-type and holes in p-type
D. free electrons in n-type and p-type

298. The velocity of an oscillating charge as it moves to and fro along a wire is always_____________?
A. constant
B. zero
C. changing
D. infinite

299. Which one of the following has the greatest energy gap ?
A. insulator
B. conductor
C. semi conductor
D. any of above

300. Thermions are________________?
A. protons
B. positrons
C. electrons
D. photons