JEE Main Physics - Solids and Semiconductor Devices
Exam Duration: 60 Mins Total Questions : 30
Sodium chloride crystal is by nature
- (a)
dielectric
- (b)
conductor
- (c)
semiconductor
- (d)
metal
Sodium chloride is
- (a)
ionic crystal
- (b)
covalent crystal
- (c)
semi-conductor
- (d)
insulator
Copper has atomic radius \(1.273\mathring {A}\).Cu
- (a)
is fcc lattice
- (b)
has bond length \(2.546\mathring {A}\)
- (c)
has lattice constant \(3.60\mathring{A}\)
- (d)
all of the above
The type of binding in germanium crystal is
- (a)
ionic
- (b)
metallic
- (c)
covalent
- (d)
van der Waals
Which of the following solids make the best mirrors?
- (a)
ionic solids
- (b)
covalent solids
- (c)
metallic solids
- (d)
dielectric solids
The pure semiconductor has
- (a)
an infinite resistance at \({ 0 }^{ \circ }\)C
- (b)
a finite resistance which does not change with temperature
- (c)
a finite resistance which decreases with temperature
- (d)
a finite resistance which increases with temperature
The value of \(\beta\)
- (a)
is always less than 1
- (b)
lies between 50 and 150
- (c)
is always greater than 150
- (d)
is always 100
The depletion layer in the pn junctions is caused by
- (a)
drift holes
- (b)
drift of electrons
- (c)
diffusion of carrier ions
- (d)
migration of impurity ions
Electric Conductivity increases with increase in temperature of
- (a)
intrinsic semi-conductor
- (b)
n-type semi-conductor
- (c)
p-type semi-conductor
- (d)
None of the above
In an n-p-n transistor, the collector currents is 10mA.If 90% of the electrons emitted reach the collector
- (a)
the emitter current will be 11 mA
- (b)
the base current will be 0.1mA
- (c)
both (a) and (b) are correct
- (d)
none of the above
The electrical conductivity of a semi conductor increases when electromagnetic radiation of wavelength shorter than 2480 nm is incident on it.The band gap (in eV) for semiconductor is
- (a)
0.9
- (b)
0.7
- (c)
0.5
- (d)
1.1
The energy gap of a silicons is 1.14 eV.The maximum wavelength at which silicon absorbs energy is
- (a)
10.888\(\mathring { A } \)
- (b)
\(108.88\mathring { A } \)
- (c)
\(1088.8\mathring { A } \)
- (d)
\(10888\mathring { A } \)
Resistivity of a semiconductor depends on
- (a)
shape of semiconductor
- (b)
atomic nature of semiconductor
- (c)
length of semiconductor
- (d)
shape and atomic nature of semiconductor
If the drift velocity and mobility of electrons in a semiconductor are represented by \(\vartheta \)and \(\mu\) respectively and the applied electric field is E, then
- (a)
\(\mu =\frac { \vartheta }{ E } \)
- (b)
\(\mu =\vartheta E\)
- (c)
\(\mu =\frac { E }{ \vartheta } \)
- (d)
None of the above
N-type germanium is obtained on doping intrinsic germanium by
- (a)
aluminium
- (b)
boron
- (c)
phosphorus
- (d)
gold
The electric field set up across the potential barries is \({E}_{si}\) for a diode and \({E}_{Ge}\)for a germanium diode.Then, the ratio \(\frac {{E}_{Si}} {{E}_{Ge}}\)is approximately
- (a)
2
- (b)
0.5
- (c)
0.3
- (d)
3
In a halfwave rectifier, the r.m.s value of the a.c. component of the wave is
- (a)
equal to d.c value
- (b)
more than d.c value
- (c)
less than d.c value
- (d)
zero
An oscillator is an amplifier with
- (a)
large gain
- (b)
continuous a.c supply
- (c)
negative feedback
- (d)
positive feedback
Choose the correct statement
- (a)
A rectifier converts a.c into d.c
- (b)
An oscillator converts d.c into a.c.
- (c)
Transistor biasing provides proper flow of zero collector current
- (d)
All of these
In common-emitter circuit, the voltage gain is
- (a)
lowest
- (b)
highest
- (c)
zero
- (d)
Same as in common-base circuit
How many NAND gates used to form AND gate?
- (a)
1
- (b)
2
- (c)
3
- (d)
4
The following truth table corresponds to the logic gate
A | B | x |
0 | 0 | 0 |
0 | 1 | 1 |
1 | 0 | 1 |
1 | 1 | 1 |
- (a)
NAND
- (b)
OR
- (c)
AND
- (d)
XOR
The band gap inGe and Si ineV respectively is
- (a)
0.7,1.1
- (b)
1.1,0.7
- (c)
1.1,0
- (d)
0,1.1
Two wires P and Q made up of different materials have some resistance at room temperatures.When heated,resistance of P increases and that of Q decreases.We may conclude that
- (a)
P and Q are both conductors but because of being made of different materials it happens so.
- (b)
P is n-type semiconductor and Q is p-type semiconductor
- (c)
P is semiconductor and Q is conductor
- (d)
P is conductor and Q is semiconductor
In p-type semiconductor
- (a)
major current carrier is electrons
- (b)
major current carrier is mobile negative ions
- (c)
major current carrier is mobile holes
- (d)
the number of mobile holes exceeds the number of accepter