Question 1 :
The energy gap between the valence band and the condition band for a material is $6$eV. The material is?
Question 2 :
What is the resistivity of a pure semiconductor at absolute zero ?
Question 3 :
A semi conductor device with both active and passive electronic elements diffused into a silicon water to form a functional circuit is called.
Question 6 :
A strip of copper and another of germanium are cooled from room temperature to $80\ K$. The resistance of<br>
Question 7 :
The band gap in silicon and germanium ( in eV) respectively is
Question 9 :
The distinction between conductors, insulators and semiconductors is largely concerned with
Question 11 :
In an intrinsic semiconductor, the number of electrons in the conduction band is ________ the number of holes in the valence band.<br/>
Question 16 :
In a metal, the separation between conduction band and valence band is of the order<br/>
Question 23 :
In semiconductors, the forbidden energy gap between valence band and conduction band is of the order of :<br/>
Question 27 :
Bands in solids are formed due to a group of closely spaced ________ .
Question 29 :
Which one of the following statements is not correct in case of a semiconductor?
Question 31 :
Assertion: Intrinsic semiconductors are doped
Reason: Holes or electrons are supplied by a foreign atom acting as an impurity
Question 33 :
Which of the following is an example of a direct band gap intrinsic semiconductor?
Question 35 :
Which of the following has least band gap energy at $273K$.
Question 39 :
Assertion: Intrinsic semiconductors are undoped
Reason: Holes in the valence band are vacancies created by electrons that have been thermally excited to the conduction band
Question 40 :
When the conductivity of a semiconductor is only due to breaking of covalent bonds, the semiconductor is called<br/>
Question 42 :
The level formed due to impurity atom, in the forbidden energy gap, very near to the valence band in a P-type semiconductor is called
Question 43 :
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $600\ nm$ is incident on it. The energy band gap (in eV) for the semiconductor is
Question 44 :
The value indicated by Fermi energy level in an intrinsic semiconductor is<br/>
Question 45 :
The relationship between band gap energy and temperature can be described by ____________.
Question 49 :
The level formed due to impurity atom,in the forbidden energy gap,very near to the valence band in a p-type semiconductor is called<br/>
Question 52 :
The energy gap $E_G$ of a semi-conductor decreases with rise in temperature.<br/>
Question 54 :
The charge on a hole is equal to the charge of
Question 55 : <p> If the resistivity of an alloy is $\rho '$ and that of constituent metal is $\rho $ then :</p>
Question 58 :
State whether True or False :A semiconductor at absolute zero become a insulator.
Question 59 :
If we add impurity to a metal those atoms also deflect electrons. Therefore,
Question 63 :
The plate current in a diode is zero. It is possible that
Question 64 : Match the following<table class="wysiwyg-table"><tbody><tr><td>a) p-type semiconductor</td><td>1) Pure semiconductor</td></tr><tr><td>b) Intrinsic semiconductor</td><td>2) Doped with impurity</td></tr><tr><td>c) Extrinsic semiconductor</td><td>3) majority carriers are electrons</td></tr><tr><td>d) n-type semiconductor</td><td>4) majority carriers are holes</td></tr></tbody></table>
Question 67 :
Assertion: The energy bands in a solid correspond to the energy levels in an atom.
Reason: An electron in a solid can have only energies that fall with these energy bands.
Question 69 :
In a semiconductor, the energy gap between valence band and conduction band is of the order of.
Question 70 :
In an intrinsic semiconductor, the density of conduction electrons is $7.07\times 10^{15}m^{-3}$. When it is doped with indium, the density of holes becomes $5\times 10^{22}m^{-3}$. Find the density of conduction electrons in doped semiconductor
Question 71 :
The valence of an impurity added to germanium crystal in order to convert it into a $P-$ type semi conductor is
Question 72 :
In a good conductor the energy gap between the conduction band and the valence band is
Question 74 :
When the electrical conductivity of a semi-conductor is due to the breaking of its covalent bonds, then the semiconductor is said to be
Question 75 :
The energy gap of silicon is $1.14\ eV$. The maximum wavelength at which silicon will begin absorbing energy is
Question 76 :
The laptop PC's modern electronic watches and calculator use the following for display
Question 77 :
Carbon, Silicon and Germanium atoms have limn valenceelectrons each. Their valence and conduction bands areseparated by energy band gaps represented by $\displaystyle (E_g)_c,(E_g)_{si}$and $\displaystyle (E_g)_{Ge}$respectively. Which one of the followingrelationship is true in their case?
Question 78 :
The electrical conductivity of a semiconductor increases when radiation of the wavelength shorter than $2480nm$ is incident on it.The bandgap (in eV) for the semiconductor is
Question 80 :
In germanium, the energy gap is about $0.75\ eV$. Thewavelength of light which germanium starts absorbing is
Question 82 :
Electrical conductivity of a semiconductor increases when em radiation of $\lambda<2480nm$ is incident on it. The band gap in (ev) for the semiconductor is<br>
Question 83 :
Energy band gap between valence band and conduction band for semiconductor is:
Question 84 :
State whether given statement is True or False<br/>The probability of electrons to be found in the conduction band of an intrinsic semiconductor at a finite temperature decreases exponentially with increasing bandgap.
Question 86 :
The forbidden energy gap for germanium crystal at $0 K$ is
Question 88 :
A hole is drilled in a copper sheet. The diameter of the hole is 4.24 cm at 27.0$^{\circ}$C. What is the change in the diameter of the hole when the sheet is heated to 227$^{\circ}$C? Coefficient of linear expansion of copper is 1.70 x 10$^{-5}$ 
Question 89 :
Assertion: Semiconductors are solids with conductivities in the intermediate range from ${10}^{-6}-{10}^{4}$ ${ohm}^{-1}{m}^{-1}$.
Reason: Intermediate conductivity in semiconductor is due to partially filled valence band.
Question 91 :
In insulators the forbidden energy gap between the valence band and conduction band is of $ \ldots \ldots \ldots $ value:
Question 92 :
A p-n photodiode is fabricted from a semiconductor with a band gap of 2.5eV. It can detect a signal of wavelength
Question 93 :
Assertion: At absolute zero semiconductors behaves as the ideal insulator.
Reason: In semiconductor electron vibration happen at room temperature. But at very low-temperature electron can not get energy and so it can not vibrate. and so current can not pass,so semiconductor act as an insulator.
Question 95 :
<br/>In metals, the conduction bands are incompletely filled orbitals that allow electrons to flow.
Question 96 :
The expected energy of the electrons at absolute zero is called 
Question 97 :
<br/>In insulators, the valence bands are completely and the large band gap prevents the promotion of electrons to empty space whereas in semiconductor band gap is low.
Question 98 :
Three semi-conductor are arranged in the increasing order of their energy gap as follows. The correct arrangement is
Question 99 :
A pn photo diode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength :<br><br>
Question 100 :
In a semiconductor the separation between conduction band and valence band is of the order of
Question 101 :
<br/>A transformer has 500 turns in its primary and 1000 turns in its secondary winding.The primary voltage is 200 V and the load in the secondary is 100 ohm.Calculate the current in the primary,assuming it to be a ideal transformer.<br/>
Question 102 :
Mobilities of electrons and holes in a sample of intrinsic germanium at room temperature are $0.36m^2V^{-1}s^{-1}$ and $0.17m^2V^{-1}s^{-1}$. The electron and hole densities are each equal to $2.5\times 10^{19}m^3$. The electrical conductivity of germanium is
Question 103 :
The energy gap of silicon is $1.14\ eV$. The maximum wavelength at which silicon starts energy absorption, will be ($h = 6.62$ $\times$ <br> $ 10$ <br> $^{-34}$ <br> $Js$, $c = 3$ $\times$ $10$ <br> $^8$ <br> $ m/s$)<br/>
Question 104 :
An electron hole pair is formed when light of maximum wavelength $6000\overset {\circ}{A}$ is incident on the semiconductor. What is the band gap energy of the semiconductor?<br>$(h = 6.62\times 10^{-34} J-s)$.
Question 105 :
A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of:<br/>
