Multiple Choice Question/ Objective question Electrical Material Part -5 for Competition Exam

Q.1. Plastics are

      (a)  Good conductors of heat

      (b)  Bad conductors of electricity

      (c)  Good conductors of electricity

      (d)  High density
Ans (c)

Q.2. In order to obtain p-type germanium it should be doped with a

      (a)  Trivalent impurity

      (b)  Tetravalent impurity

      (c)  Pentavalent impurity

      (d)  None of the above
Ans (a)

Q.3. Barrier potential in a P-N junction is caused by

      (a)  Thermally generated electrons and holes

      (b)  Diffusion of majority carriers across the junction

      (c)  Migration of minority carriers across the junction

      (d)  Flow of drift current
Ans (b)

Q.4. The heating elements of electric irons are made of

      (a)  Copper

      (b)  Nichrome.

      (c)  Constantan

      (d)  aluminium
Ans (b)

Q.5. Hard ferrites are used for making

      (a)  Transformer cores

      (b)  Electrical machinery

      (c)  High frequency equipment

      (d)  Light weight permanent magnets
Ans (d)

Q.6. The main constituents of glass is

      (a)  SiO2 

      (b)  B2O3

      (c)  Al2O3 

      (d)  Cr2O3
Ans (a)


Q.7. Micanite is a form of

      (a)  Built up mica

      (b)  Hydrated potassium aluminium silicate

      (c)  Magnesium mica.

      (d)  Calcium mica.
Ans (a)

Q.8. P-N junction is

      (a)  a rectifier

      (b)  an amplifier

      (c)  an Oscillator

      (d)  a Coupler
Ans (a)

Q.9. That is the type of bonding in silicon

      (a)   Ionic

      (b)  Covalent 

      (c)   Metallic

      (d)   Ionic + Metallic
Ans (b)

Q.10. The conductivity of an extrinsic semiconductor

      (a)   Decreases with temperature

      (b)   Increases with temperature

      (c)   Remains constant with temperature

      (d)   decreases and then increases with temperature
Ans (b)

Q.11. 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
Ans (a)

   
Q.12. A transistor has

      (a)   One p-n junction

      (b)   Two p-n junction

      (c)   Four p-n junction

      (d)   Five p-n junction
Ans (b)

Q.13. Hall effect is associated with

      (a)   Conductors

      (b)   Semiconductors

      (c)   Thermistors

      (d)   solders
Ans (b)

Q.14. Addition of trivalent impurity to a semiconductor creates many

      (a)   Holes

      (b)   Free electrons

      (c)   Valance electrons

      (d)   Bound electrons
Ans (b)

Q.15. Atoms with four valence electrons are good conductors

      (a)   True

      (b)   False

      (c)   None of the above

      (d)   Not confirm
Ans (b)