Semi-conductors Objectives Part 01

01 . Semi-conductor device constitutes an active component.

02 . SCR is an active device.

03 . The conductivity of materials found in nature ranges from 109 ohm-1m-1 to nearly 10-18 ohm-1

m-1. From this it can be concluded that the conductivity of silicon in ohm cm will be nearly 0.5×10-3.

04 . The process by which impurities are added to a pure semi-conductor is Doping.

05 . Capacitors are passive components.

06 . Capacitor is used as a passive component in electronic circuits.

07 . A Germanium atom contains four valance electrons.

08 . If the conductivity of pure germanium is 1.54 siemens/meter, its resistivity in ohm-meter will be nearly 0.065.

09 . The type of atomic bonding in most common in semi-conductor is Covalent.

10 . When an atom either gains or losses an electron it is said to be ionized.

11 . The diameter of an atom is 10-10 meter.

12 . The atomic weight of an atom is determined by the number of protons and neutrons.

13 . The mass of proton and neutron is nearly the same.

14 . The number of protons in an atom is called its atomic number.

15 . The maximum number of electrons in third orbit can be 18.

16. Valence electrons are the electrons present in outermost orbit.

17 . Boron has lowest atomic number.

18 . Helium element does not occur in third group of periodic table.

19 . The atomic number of silicon is 14. It can be therefore concluded that
a) a silicon atom contains 14 protons
b) a silicon atom contains 14 neutrons
c) a silicon atom contains 14 electrons.

20 . If the atomic number of germanium is 32, the number of electrons in the outermost shell will be 4.