Quiz 3

1. The resistivity of a semiconductor lies between 

• (a)10 ^-6 Ωm to10^-8 Ωm
• n(b) 10⁸ Ωm to10¹⁴ Ωm
• (c) 10 ^-2 Ωm to10⁴ Ωm
• (d) none of these

2. The forbiddenn energy gap for Germanium is of the order of

• (a) 0.7 eV
• (b) 0.3 eV
• (c) 1.1 eV
• (d) 10 eV

3. Which of the following is a pentavalent impuity added while forming an extrinsic semiconductor ?

• (a) Boron 
• Arsenic
• Indium
• Gallium

Doping of Semiconductors

• materials which can conduct electricity better than insulator, but not as well as conductors.

• The process of adding of a certain amount of specific impurities atoms in the pure semiconductor.

• when 4 electrons in outermost orbit.

Which of the following statements is NOT the diode application in electronic circuit?

• Diode as voltage regulator

• Diode as Rectifier

• Diode as Amplifier

• Diode as solar cell

A full-wave rectifier consist of _______________________________

• 1 Diode

• 2 Diode

• 3 Diode

• 4 Diode

Basic building blocks of all electronic circuits are

• Devices in which there is a flow of electrons

• devices in which there is no flow of electrons

• devices in which there is a controlled flow of electrons

• devices in which there is an uncontrolled flow of electrons

conductivity of semiconductor increases with increase in temperature, because

• number density of free charge carriers increases

• relaxation time increases

• both number density of free charge carriers and relaxation time increases

• number density of free charge carriers increases relaxation time decreases but effect of decrease in relaxation time is much less than increase in number density

Let n_p and n_e be the number density of holes and conduction electrons respectively in a semiconductor. Then,

• n_{p >} n_e in an intrinsic semiconductor, I < I_p + I_e

• n_{p =} n_e in an extrinsic semiconductor, I > I_p + I_e

• n_{p =} n_e in an intrinsic semiconductor, I = I_p + I_e

• n_{p >} n_e in an intrinsic semiconductor, I = 0( Here, I_p = current due to holes,I_e= current due to electrons, I= total current)

During formation of p-n junction

• an electron diffuses from n to p side

• a hole diffuses from p to n side

• a hole diffuses from n to p side

• an electron diffuses from p to n side