Test: Electronic Devices - 2 - CUET Humanities MCQ

Whenever an impurity is added, the semiconductor remains electrically neutral because the number of electrons and the number of protons added are the same or we can say the impurity added is an atom and not a positive or negative ion.

Conductivity of the semiconductors increases with increase in temperature. So, statement 4 is false.

Some of the electrons from the valence band may gain external energy to cross the gap between the conduction band and the valence band. Then, these electrons will move into the conduction band. At the same time, they will create vacant energy levels in the valence band where other valence electrons can move. Thus, the process creates the possibility of conduction due to electrons in the conduction band as well as due to vacancies in the valence band.

n-type semiconductor has free moving (negative) electrons and an equal number of stationary positively charged donor ions. The ions are positively charged because they have lost one electron each. The crystal as a whole is netural.

According to the question,




Thus, y is a NOR gate.

Since all the gates can be obtained from NAND and NOR gates by using logical circuits or algebraic expressions, so these gates are universal gates.

The potential difference across the resistance = 5.5 - 0.4 = 5.1 V.
The current through the resistance is I.
So, V = IR


I = 1 mA

Output Y = 
Where A, B and C are 0 → Y = 1
When A, B and C are 1 → Y = 0

Positive part of wave is retained and negative part of wave is made positive.
Therefore, number of pulses/second = frequency × 2 = 100 Hz (pulses/second = fundamental frequency of the ripple)

The resistance of intrinsic semiconductor decreases with increase of temperature. Doping pure Si with trivalent impurities gives p-type semiconductor where as doping with pentavalent impurity gives n-type semiconductor. The majority carriers in n-type semiconductors are electrons. A p-n junction can act as a semiconductor diode.