11) The Gunn diode is made of
a) Silicon
b) Germanium
c) Gallium Arsenide
d) Selenium
12) Which one of the following is not a characteristic of a ferroelectric material?
A. High dielectric constant
B. No hysteresis
C. Ferroelectric characteristic only above the curie point
D. Electric dipole moment
13)A bipolar junction transistor has a common base forward short circuit current gain of 0.99. its common emitter forward short circuit current gain will be
a) 50
b) 99
c) 100
d) 200
14) In fabricating silicon BJT in ICs by the epitaxial process, the number of diffusions sued is usually
a) 2
b) 3
c) 4
d) 6
15) An electron in the conduction band
has higher energy than the electron in the valence band
has lower energy than the electron in the valence band
loses its charge easily
jumps to the top of the crystal
16) What is the approximate mobility of holes in Germanium at room temperature ?
a) 4500 cm2/V.s
b) 2400 cm2/V.s
c) 1800 cm2/V.s
d) 900 cm2/V.s
17)In which one of the following, two optical polarisers, one in front and other in back are needed ?
a) LED
b) LCD
c) LDR
d) LSI
18)A tunnel diode is
a) High resistivity p-n junction diode
b) A slow switching device
c) An amplifying device
d) A very heavily doped p-n junction diode
19) An SCR remains turned on if the anode current is more than the :
a) Break over current
b) Trigger current
c) Holding current
d) Threshold current
20) Mobility is defined as
a) diffusion velocity per unit field
b) drift velocity per unit field
c) displacement per unit filed
d) number of free electrons/number of bound electrons