Center for Development of Advanced Computing

C-DAC Project Engineers,

Electronics & Communication Engineering

Q.1.There are ................ basic crystal systems

• two
• four
• six
• seven

Q.2.A suitable material for VHF (Very high frequency) application is

• silicon steel
• alnico
• cobalt steel
• ferrite

Q.3.Heating in microwave oven is due to

• magnetostriction
• electrostriction
• eddy current
• spontaneous polarization

Q.4.Line insulators are made of

• porcelain
• mica
• marble
• PVC

Q.5.Insulating materials that can withstand a temperature above 1800 C is of

• Class A type
• Class B type
• Class C type
• Class H type

Q.6.Displacement current in a dielectric primarily depends upon the

• resistivity
• dipole moment
• frequency of operating field
• mobility

Q.7.In an imperfection free crystal, the resistivity will be

• infinite
• zero
• negative
• unity

Q.8.A metallic bond is formed from

• sharing of electrons
• transfer of electrons
• sharing of variable number of electrons by a variable number of atoms
• None of these

Q.9.The work function (W) is  given by the relation :

• W = h2f0
• W = hf0
• W = hf02
• W = h2f02

Q.10.Einstein's photoelectric equation is given by

• hf  = W2 + 1/2 mv2
• hf  = W + 1/2 m2v2
• hf  = W + 1/2 mv2
• hf  = W2 + 1/2 m2v2

Q.11.X-rays were discovered accidently by Professor Rontgen in

• 1870
• 1885
• 1895
• 1900

Q.12.Bragg's law is given by the equation

• 2d2 sin ? = n?
• 2d sin2  ? = n?
• 2d sin ? = n?
• 2d2 sin ? = n?2

Q.13.In some applications neutron diffraction is much ........ to X-rays & electron diffraction

• inferior
• superior
• either of the above
• none of these

Q.14.The co-ordination number is twelve for a

• H.C.P. structure
• F.C.C. structure
• S.C. and F.C.C. structure
• H.C.P. and F.C.C. structure

Q.15.The quantity 1/vµ0e0 in  SI units has the

• Value 330 m/s
• Value 1.73*104
• Dimensions LT1
• None of the above

Q.16.Which of the following does not have the same units as the others? The symbols have their usual meanings

• L/R
• RC
• vLC
• 1/vLC

Q.17.n-type semi-conductors

• are negatively charged
• are produced when indium is added as an impurity to germanium
• are produced when phosphorous is added as an impurity to silicon
• none of these

Q.18.Which of the following statements correct?

• Copper has partially filled conduction band
• Diamond has a completely filled conduction band but an empty valence band
• Silicon has a partially  filled conduction band and an empty valence band
• Energy gap between conduction and valence band in diamond is smaller than in silicon

Q.19.Which of the following will serve as a donor impurity in silicon?

• Boron
• Indium
• Germanium
• Antimony

Q.20.Two-closed packed crystal structures are

• bcc and fcc
• fcc and hcp
• bcc and hcp
• fcc  and sc 

Q.21.The mean free path for electron drift increase with

• purity
• strain hardening 
• elastic modulus 
• none of the above

Q.22.Two group IV elements have the same diamond cubic structure. The  one with the larger ................ is expected to have the smaller energy gap.

• packing factor
• co-ordination number
• number of valence electrons
• atomic weight

Q.23.The processes that can be used to make the steel magnetically softer are 1. Annealing 2. Grain growth 3. Decarburization 4. Quenching

• 1, 2 and 3
• 2, 3 and 4
• 2 and 3 only
• 3 and 4 only

Q.24.Polarization is a measure of

• dielectric constant per unit volume
• voltage gradient of produce eslectrical breakdown
• product of charge and distance
• excess charge density

Q.25.Consider the following semi-conductor diodes 1. Germanium diode 2. Silicon diode 3. Tunnel diode 4. Schottky diode The correct increasing order of forward voltage drop of these diodes is

• 1,3,2,4
• 1,2,3,4
• 3,4,2,1
• 3,1,4,2

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