Physics : Semiconductor Electronics: Materials, Devices and Simple Circuits

The voltage gain of the following amplifier is

• 10

• 100

• 1000

• 9.9

Assertion:  A diode lasers are used as optical sources in optical communication.

Reason: Diode lasers consume less energy.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion: The logic gate NOT can be built using diode.

Reason: The output voltage and the input voltage of the diode have 180^o phase difference.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion: In a common emitter transistor amplifier the input current is much less than the output current. 

Reason: The common emitter transistor amplifier has very high input impedance.

• If both assertion and reason are true and reason is the correct explanation of assertion 

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false.

The temperature  (T)  dependence of resistivity ( ρ ) of a semiconductor is represented by

Which logic gate is represented by the following combination of logic gates?

• OR

• NAND

• AND

• NOR

A Ge specimen is doped with Al. The concentration of acceptor atoms is  ∼ 10²¹ atoms/m³. Given that the intrinsic concentration of electron-hole pairs is  ∼ 10¹⁹/m³, the concentration of electrons in the speimen is

• 10¹⁷/m³

• 10¹⁵/m³

• 10⁴/m³

• 10²/m³

Assertion: In a transistor the base is made thin. 

Reason: A thin base makes the transistor stable.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion 

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion:  In He-Ne laser, population inversion takes place between energy levels of neon atoms. 

Reason:  Helium atoms have a meta-stable energy level.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion: A transistor amplifier in common emitter configuration has a low input impedence.

Reason: The base to emitter region is forward biased.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false