Question 1 :
The state of the energy gained by valence electron when the temperature is raised or when electric field is applied is called as
Question 4 :
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $1240 nm$, is incident on it. The band gap for the semiconductor is:<br/>
Question 5 :
In case of a semiconductor, which of the following statement is wrong
Question 6 :
The band gap in Germanium and silicon in $eV$ respectively is
Question 7 :
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 8 :
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 10 :
The intrinsic charge carrier density in germanium crystal at $ 300 K is 2.5 \times 10^{13} / cm^3 $. density in an n-type germanium crystal at 300 K be $ 5 \times 10^{16} /cm^3 $,the hole density in this n-type crystal at 300 K would be
Question 11 :
In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of
Question 12 :
The valence band and conduction band of a solid overlap at low temperature, the solid may be
Question 14 :
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 16 :
In the bandgap between valence band and conduction band in a material is $5.0eV$, then the material is
Question 19 :
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 20 : 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 21 :
The plate current in a diode is zero. It is possible that
Question 22 :
The electrical conductivity of a semiconductorincreases when electromagnetic radiation ofwavelength shorter than $2480\ nm$ is incident onit. The forbidden band energy for the semiconductor in $eV$ is<br>
Question 24 :
Energy band gap between valence band and conduction band for conductor is:
Question 26 :
When the $P$ end of $P-N$ junction is connected to the negative terminal of battery and the $N$ end to the positive terminals of the battery, then the $P-N$ junction behaves like
Question 27 :
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 28 :
In a good conductor the energy gap between the conduction band and the valence band is
Question 29 :
The energy gap between the valence band and the conduction band for the material is $>9eV$. Identify the material.
Question 30 :
The energy gap of silicon is $1.14\ eV$. The maximum wavelength at which silicon will begin absorbing energy is
Question 31 :
The highest occupied energy band is called ________ and lowest unoccupied energy band is called the _________ .<br/>
Question 32 :
If the energy gap of a semiconductor is 1.1 e V it would be:<br>
Question 34 :
In germanium, the energy gap is about $0.75\ eV$. Thewavelength of light which germanium starts absorbing is
Question 36 :
The band gap for a pure semiconductor is $2.1 eV$. The maximum wavelength of a photon which is able to create a hole-electron pair is nearly :<br/>
Question 37 :
Silicon is a semiconductor. If a small amount of As is added to it then its electrical conductivity
Question 41 :
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 43 :
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $2480\ nm$ is incident on it. The band gap (in $eV$) for the semiconductor is
Question 44 :
The band gaps of an insulator, conductor and semi conductor are respectively $E_{g1}$, $E_{g2}$ and $E_{g3}$. The relationship between them is given as ____________.
Question 46 :
The forbidden gap for a pure silicon at the room temperature is _______eV.<br/>
Question 47 :
If we add impurity to a metal those atoms also deflect electrons. Therefore,
Question 48 :
If electromagnetic rays are incident on a semiconductors its conductivity .
Question 49 :
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 50 :
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
