Pure Si at 500 K has equal number of electron (ne) and hole (nh) concentrations of 1.5 $$ \times $$ 1016 m$$-$$3. Doping by indium increases nh to 4.5 $$ \times $$ 1022 m$$-$$3. The doped semiconductor is of
A
p-type having electron concentration ne = 5 $$ \times $$ 109 m$$-$$3
B
n-type with electron concentration ne = 5 $$ \times $$ 1022 m$$-$$3
C
p-type with electron concentration ne = 2.5 $$ \times $$ 1010 m$$-$$3
D
n-type with electron concentration ne = 2.5 $$ \times $$ 1023 m$$-$$3
2
AIPMT 2011 Prelims
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
A transistor is operated in common emitter configuration at VC = 2 V such that a change in the base current from 100 $$\mu $$A to 300 $$\mu $$A produces a change in the collector current from 10 mA to 20 mA. The current gain is
A
50
B
75
C
100
D
25
3
AIPMT 2011 Prelims
MCQ (Single Correct Answer)
+4
-1
Symbolic representation of four logic gates are shown as
Pick out which ones are for AND, NAND and NOT gates, respectively
A
(ii), (iii) and (iv)
B
(iii), (ii) and (i)
C
(iii), (ii) and (iv)
D
(ii), (iv) and (iii)
4
AIPMT 2011 Prelims
MCQ (Single Correct Answer)
+4
-1
If a small amount of antimony is added to germanium crystal
A
it becomes a p-type semiconductor
B
the antimony becomes an acceptor atom
C
there will be more free electrons than holes in the semiconductor
