Electronic Devices and Circuits

1.At room temperature the current in an intrinsic semiconductor is due to
holes electrons ions holes and electrons

2.The most commonly used semiconductor material is
silicon germanium mixture of silicon and germanium none of the above

3.In which of these is reverse recovery time nearly zero?
Zener diode Tunnel diode Schottky diode PIN diode

4.In an n channel JFET, the gate is
n type p type either n or p partially n & partially p

5.The amount of photoelectric emission current depends on
frequency of incident radiation intensity of incident radiation both frequency and intensity of incident radiation none of the above

6.At very high temperatures the extrinsic semi conductors become intrinsic because
drive in diffusion of dopants and carriers band to band transition dominants over impurity ionization impurity ionization dominants over band to band transition band to band transition is balanced by impurity ionization

7.When a voltage is applied to a semiconductor crystal then the free electrons will flow.
towards positive terminal towards negative terminal either towards positive terminal or negative terminal towards positive terminal for 1 μs and towards negative terminal for next 1 μs

8.Ferrite have
low copper loss low eddy current loss low resistivity higher specific gravity compared to iron

9.In an n-p-n transistor, the majority carriers in the base are
electrons holes both holes and electrons either holes or electrons

10.The number of doped regions in PIN diode is
1 2 3 1 or 2

Materials and Components

1.Which capacitor-store higher amount of energy?
Air capacitor Paper capacitor Mica capacitor Plastic film capacitor

2.In paramagnetic materials
permanent magnetic dipoles exist but the interaction between neighbouring dipoles is negligible permanent magnetic dipole do not exist permanent magnetic dipoles exist and the interaction between neighbouring dipoles is very strong permanent magnetic dipole moment may or may not exist

3.The core of a coil has a length of 10 cm. The self inductance is 8 mH. If the core length is doubled, all other quantities remaining the same, the self inductance will be
32 mH 16 mH 8 mH 4 mH

4.Two materials having temperature coefficients of 0.004 and 0.0004 respectively are joined in series. The overall temperature coefficient is likely to be
0.08 0.04 0.001 0.0001

5.The number of valence electrons in pentavalent impurity is
5 4 3 1