1.Adding impurities to a pure semiconductor is called

a.doping

b.filtering

c.diffusion

d.refraction

2.Which of the elements below is not a semiconductor?

a.Gallium

b.Arsenic

c.Copper

d.Indium

3.Acceptor atoms have a valency of

a.3

b.4

c.5

d.8

4.Which expression is correct in describing the currents in a transistor?

a.Ic = Ie + Ib

b.Ie = Ic + Ib

c.Ib = Ie + Ic

d.Ib + Ic + Ie = 0

5.The voltage drop across a conducting LED is

a.0.7 volts

b.1.7 volts

c.2.7 volts

d.3.7 volts

[ANSWERS]

Updated on 17 Dec 2000
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