1. The total energy of a revolving electron
in an atom can
(a) have any value above zero
(b) never be positive
(c) never be negative
(d) not be calculated.
2. An atom is said to be ionised when any
one of its orbiting electron
(a) Jumps from one orbit to another
(b) is raised to a higher orbit
(c) comes to the ground state
(d) is completely removed.
3. The maximum number of electrons which
the M-shell of an atom can contain is
(a) 32
(b) 8
(c) 18
(d) 50.
4. Electronic distribution of an Si atom is
(a) 2, 10, 2
(b) 2, 8, 4
(c) 2, 7, 5
(d) 2, 4, 8.
5. Semiconductor materials have ⸺ bonds.
(a) ionic
(b) covalent
(c) mutual
(d) metallic.
6. The maximum number of electrons which
the valence shell of an atom can have is
(a) 6
(b) 8
(c) 18
(d) 2
7. Silicon has Z = 14. Its outermost orbit
is
(a) partially filled
(b) half filled
(c) completely occupied
(d) empty
8. Major part of the current in an
intrinsic semiconductor is due to
(a) conduction-band electrons
(b) valence-band electrons
(c) holes in the valence band
(d) thermally-generated electron.
9. Conduction electrons have more mobility
than holes because they
(a) are lighter
(b) experience collisions less frequently
(c) have negative charge
(d) need less energy to move them.
10. Doping materials are called impurities
because they
(a) decrease the number of charge carriers
(b) change the chemical properties of semiconductors
(c) make semiconductors less than 100 percent
pure
(d) alter the crystal structures of the
pure semiconductors.
Answers
1. (b) 2. (d) 3. (c) 4. (b) 5. (b)
6. (b) 7.
(b) 8. (a) 9. (d) 10. (d)
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