Which of the following will serve as a donor impurity in silicon?
(A) Boron (B) Indium (C) Germanium (D) Antimony
Description : Impurity atoms to be added to pure silicon in order to make a p-type semiconductor belongs to (a) Phosphorous (b) Boron (c) Antimony (d) Aluminium
Last Answer : Boron , a group three element.
Last Answer : The impurity level in an extrinsic semiconductor is about 1 atom for 108 atoms of pure semiconductor.
Last Answer : Addition of trivalent impurity to a semiconductor creates many Holes.
Last Answer : A trivalent impurity has 3 valence electrons.
Last Answer : A pentavalent impurity has 5 Valence electrons.
Last Answer : Addition of pentavalent impurity to a semiconductor creates many Free electrons.
Last Answer : When a pentavalent impurity is added to a pure semiconductor, it becomes n-type semiconductor.
Description : __________ is a donor impurity for semi-conductors. (A) Boron (B) Antimony (C) Gallium (D) None of these
Last Answer : (B) Antimony
Description : In an n-type semiconductor, as the donor concentration ND increases, the Fermi level EF: (1) Remains unaltered (2) Moves towards the conduction band (3) Move towards the center of forbidden energy gap (4) May or may not move depending on temperature
Last Answer : In an n-type semiconductor, as the donor concentration ND increases, the Fermi level EF: Moves towards the conduction band
Description : When a sample of germanium and silicon having same impurity density are kept at room temperature then Resistivity of silicon will be higher than that of germanium, Why?
Last Answer : Ans-The answer is simple. Consider the PN diode for Ge 0.3eV is the breakdown voltage and in the case of Si its 0.7eV since the impurities are added in the same amount the bond due to the other atoms of the Si makes it resistive compared to the Ge.. thats all!
Description : Pure silicon is (a) a p-type semiconductor (b) an n-type semiconductor (c) an intrinsic semiconductor (d) an extrinsic semiconductor
Last Answer : Pure silicon is an intrinsic semiconductor because its own electrons are responsible for conduction.
Description : Gold is often diffused into silicon PN junction devices to (A) increase the recombination rate (B) reduce the recombination rate (C) make silicon a direct gap semiconductor (D) make silicon semi-metal
Last Answer : To increase the combinational rate at the pn junction
Description : The Maximum spectral response of the germanium and silicon is in the (A) infrared region (B) ultraviolet region (C) visible region (D) x-ray region
Last Answer : The Maximum spectral response of the germanium and silicon is in the ultraviolet region
Description : Silicon has a preference in IC technology because (a) it is an indirect semiconductor (b) it is a covalent semiconductor (c) it is an elemental semiconductor (d) of the availability of nature oxide SiO
Last Answer : Silicon has a preference in IC technology because of the availability of nature oxide SiO
Last Answer : At room temperature, an intrinsic silicon crystal acts approximately as An insulator.
Last Answer : Yes. লেই Washing the unclean place will make you clean
Description : When the sample of copper with the zinc impurity is to be purified by electrolysis, the appropriate electrodes are
Last Answer : When the sample of copper with the zinc impurity is to be purified by electrolysis, the appropriate electrodes ... "),("Pure Zinc","ImPure Zinc"):}`
Description : Which one of the following elements is present as a major impurity in pig iron ?
Last Answer : Which one of the following elements is present as a major impurity in pig iron ? A. graphite B. oxygen C. sulphur D. silicon
Description : Silver is refined by cupellation process, the process removes the impurity of:
Last Answer : Silver is refined by cupellation process, the process removes the impurity of: A. Cu B. Au C. Pb D. Pt
Description : The chief impurity present in bauxite is
Last Answer : The chief impurity present in bauxite is A. `SiO_(2)` B. `Fe_(2)O_(3)` C. `K_(2)SO_(4)` D. NaF
Description : Silver containing lead as an impurity is not purified by
Last Answer : Silver containing lead as an impurity is not purified by A. Poling B. Distillation C. cupellation D. Levigation
Description : When the sample of Cu with Zn as impurity is to be purified by electrolysis, the appropriate electrodes are :
Last Answer : When the sample of Cu with Zn as impurity is to be purified by electrolysis, the appropriate electrodes are ... 4)","Impure zinc","Impure sample"):}`
Description : When copper pyrites is roasted in excess of air, a mixture of `CuO + FeO` is formed. `FeO` is present as impurity. This can be removed as slag during
Last Answer : When copper pyrites is roasted in excess of air, a mixture of `CuO + FeO` is formed. `FeO` is present ... a basic flux D. CaO, which is a basic flux
Description : Cast iron contains phosphorus as impurity. In Bessemerisation of this cast iron the slag formed is
Last Answer : Cast iron contains phosphorus as impurity. In Bessemerisation of this cast iron the slag formed is A. `FePO_(4)` B. ` ... (4)` D. `Zn_(3)(PO_(4))_(2)`
Description : If the impurity in a metal has a greater affinity for oxygen and is more easily oxidised than the metal, then the purification of metal may be carried
Last Answer : If the impurity in a metal has a greater affinity for oxygen and is more easily oxidised than ... B. electrorefining C. Zone refining D. POILING
Description : A metal contains, metal oxide as impurity. The method used to refine this metal is
Last Answer : A metal contains, metal oxide as impurity. The method used to refine this metal is A. Poling B. Liqation C. Cupellation D. Distallation
Description : The impurity present in Blister copper is
Last Answer : The impurity present in Blister copper is A. FeS B. `Cu_(2)O` C. `Cu_(2)S` D. FeO
Description : The magnetic impurity present in cassiterite ore is
Last Answer : The magnetic impurity present in cassiterite ore is A. Silica B. Wolframite C. `SnO_(2)` D. Clay
Description : Impurity along `SO_(2)` is __ and it is removed by
Last Answer : Impurity along `SO_(2)` is __ and it is removed by A. `As_(2)O_(3),Fe_(2)O_(3),xH_(2)O` B. `H_(2)S,Al(OH ... 2)O` D. `AS_(2)O_(3),Al_(2)O_(3),xH_(2)O`
Description : The impurity percentage of seed
Last Answer : Ans. Dockage
Description : __________ chloride present in crude petroleum as impurity is the most prolific producer of HCl during distillation. (A) Magnesium (B) Potassium (C) Calcium (D) Sodium
Last Answer : (A) Magnesium
Description : The impurity present in the ore?
Last Answer : Gangue
Description : Steam distillation is used for separation of high boiling (A) Substances from non-volatile impurities (B) Volatile impurity from still higher boiling substances (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) and (B)
Description : A small quantity of impurity reduces how much of conductivity of copper?
Last Answer : 35% of conductivity will be reduced due a small impurity in the conductor.
Description : Water may not contain much impurity if its source is (A) Reservoirs (B) Stream flowing in plains (C) Lakes in lower regions (D) Spring along hill slopes
Last Answer : (D) Spring along hill slopes
Description : The most detrimental impurity in high pressure boiler feed water is (A) Suspended salt (B) Dissolved salt (C) Silica (D) Turbidity
Last Answer : Option C
Description : The impurity of mixing water which affects the setting time and strength of concrete, is (A) Sodium sulphates (B) Sodium chlorides (C) Sodium carbonates and bicarbonates (D) Calcium bicarbonates
Last Answer : Answer: Option C
Description : If the iron ore contains clay as an impurity, the flux added during calcination, is (A) Clay (B) Lime stone (C) Argillaceous iron ore (D) All the above
Last Answer : Answer: Option B
Description : Which of the following is not a result of the excess of impurity in boiler-feed. a) Scale and sludge formation b) Decomposition c) Corrosion, priming and foaming d) Caustic embrittlement
Last Answer : b) Decomposition
Description : Which of the following techniques would be most useful to determine the mass of an impurity in a drug substance? A. NMR B. MS C. IR D. HPLC
Last Answer : B. MS
Description : Application of HPLC includes? A. Detection of functional groups in organic compounds B. Determination of molecular mass C. Separation of volatile compounds D. Impurity profiling
Last Answer : D. Impurity profiling
Description : A semiconductor formed by addition of trivalent impurity is : a) P–Type b) N–Type c) Q–type d) M–Type
Last Answer : d) M–Type
Description : The process of addition of impurity in pure semiconductor is : a) Doping b) Radiating c) Mixing d) Insulating
Last Answer : d) Insulating
Description : Which one of the following impurity is not desirable in the soil used for brick formation a) Alkali b) Kankar c) Iron oxide d) Alkali & Kankar*
Last Answer : d) Alkali & Kankar*
Description : Addition of trivalent impurity to a semiconductor creates many (A) holes. (B) free electrons. (C) valance electrons. (D) bound electrons.
Last Answer : (B) free electrons.
Description : When a semiconductor is doped with a P-type impurity, each impurity atom will (A) acquire negative charge. (B) acquire positive charge. (C) remain electrically neutral. (D) give away one electron.
Last Answer : (A) acquire negative charge.
Description : In order to obtain p-type germanium it should be doped with a (A) Trivalent impurity. (B) Tetravalent impurity. (C) Pentavalent impurity. (D) Any of the above will do.
Last Answer : (A) Trivalent impurity.
Description : In n type semi conductor added impurity is (A) pentavalent. (B) divalent. (C) tetravalent. (D) trivalent.
Last Answer : (A) pentavalent.
Description : Which of the following techniques would be most useful to identify and quantify the presence of a known impurity in a drug substance? A. NMR B. MS C. IR D. HPLC
Last Answer : IR
Description : Explain types of impurity added in a semiconductor with one example each.
Last Answer : There are two types of impurities added in a intrinsic semiconductor which are as follows 1.Donor Impurity 2.Acceptor Impurity 1.Donor Impurity - These are pentavalent which means they have five ... called as Acceptor doping. It is used to manufacture P-type semiconductor Eg:Boron,Gallium,Indium