1

AIPMT 2014

The given graph represents V-I characteristic for a semiconductor device.

Which of the following statement is correct ?
A
It is V-I characteristic for solar cell where, point A represents open circuit voltage and point B short circuit current.
B
It is for a solar cell and popints A and B represent open circuit voltage and current, respectively.
C
It is for a photodiode and points A and B represent open circuit voltage and current, respectively.
D
It is for a LED and points A and B represent open circuit voltage and short circuit current, respectively.

Explanation

The V-I characteristic for a solar cell is as shown the figure.
2

NEET 2013 (Karnataka)

One way in which the operation of a n-p-n transistor differs from that of a p-n-p
A
The emitter junction injects minority carries into the base region of the p-n-p
B
The emitter injects holes into the base of the p-n-p and electrons into the base region of n-p-n
C
The emitter injects holes into the base of n-p-n
D
The emitter junction is reversed biased in n-p-n

Explanation

In p-n-p transistor holes are injected into the base while electrons are injected into the base of n-p-n transistor. Emitter-base junction is forward biased.
3

NEET 2013 (Karnataka)

In an unbiased p-n junction, holes diffuse from the p-region to n-region because of
A
The attraction of free electrons of n-region.
B
The higher hole concentration in p-region than that in n-region.
C
The higher concentration of electrons in the n-region than that in the p-region.
D
The potential difference across the p-n junction.

Explanation

The higher hole concentration is in p-region than that in n-region.
4

NEET 2013

The output (X) of the logic circuit shown ion figure will be

A
X = A . B
B
X = $\overline {A + B}$
C
X = $\overline {\overline A } .\overline {\overline B }$
D
X = $\overline {A.B}$

Explanation

The output of the given logic circuit is

X = $\overline{\overline {A.B}}$ = A.B