Electronics and Communication Engineering - Electronic Devices and Circuits

26.
The diameter of an atom is
10-6 metre
10-10 metre
10-15 metre
10-21 metre
Answer: Option
Explanation:
No answer description is available. Let's discuss.

27.
N-type silicon is obtained by doping silicon with
germanium
aluminium
boron
phosphorus
Answer: Option
Explanation:
No answer description is available. Let's discuss.

28.
When a p-n junction is reverse biased
holes and electrons move away from the junction
holes and electrons move towards the junction
holes move towards junction and electrons move away from junction
holes move away from junction and electrons move towards junction
Answer: Option
Explanation:

Holes and electrons move away from junction and therefore resistance increases to a high value.


29.
If a sample of germanium and a sample of Si have the impurity density and are kept at room temperature then
both will have equal value of resistivity
both will have equal -ve resistivity
resistivity of germanium will be higher than that of silicon
resistivity of Si will be higher than of germanium
Answer: Option
Explanation:

Since the majority of charge carrier is better in Ge than in Si, for the same concentration of charge carriers, the conductivity of Ge is higher than that of Si.


30.
When a large number of atoms are brought together to form a crystal
the energy levels of inner shell electrons are affected appreciably by the presence of other neighbouring atoms.
The energy levels of outer shell electrons are affected appreciably by the presence of other neighbouring atoms.
the energy levels of both inner and outer shell electrons are affected appreciably by the presence of other neighbouring atoms.
none of the above.
Answer: Option
Explanation:

Inner shell electrons are tightly bound to the nucleus. Their energy levels cannot be affected by presence of other atoms.