1

### AIPMT 2010 Prelims

Which one of the following bonds produces a solid that reflects light in the visible region and whose electrical conductivity decreases with temperature and has high melting point ?
A
metallic bonding
B
van der Waal's bonding
C
ionic bonding
D
covalent bonding

## Explanation

In case of metal, conductivity decreases with increase in temperature and metal has high melting point.
2

### AIPMT 2010 Prelims

The device that can act as a complete electronic circuit is
A
junction diode
B
integrated circuit
C
junction transistor
D
zener diode

## Explanation

Integrated circuit can act as a complete electronic circuit.
3

### AIPMT 2010 Prelims

Which one of the following statement is false ?
A
Pure Si doped with trivalent impurities gives a p-type semiconductor.
B
Majority carries in a n-type semiconductor are holes.
C
Minority carries in a p-type semiconductor are electrons.
D
The resistance of intrinisic semiconductor decreases with increase of temperature.

## Explanation

In a n-type semiconductors, electrons are majority carriers and holes are minority carriers.
4

### AIPMT 2010 Prelims

To get an output Y = 1 in given circuit which of the following input will be correct ? A
A $\to$ 1,  B $\to$ 0,  C $\to$ 0
B
A $\to$ 1,  B $\to$ 0,  C $\to$ 1
C
A $\to$ 1,  B $\to$ 1,  C $\to$ 0
D
A $\to$ 0,  B $\to$ 1,  C $\to$ 0

## Explanation The Boolen expression for the given combination is

output Y = (A + B) · C

So it is clear that Y = 1, when A = 1, B = 0 and C = 1