Test questions for the course "Physical Electronics"

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Uploaded: 27.03.2013
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Colloquium 1

1. On the basis of a solid band model is:
a) spatial model
b) structural model
c) structural-energy model
d) the corpuscular model

2. In the derivation of thermionic emission is used:
a) a function of the velocity distribution of Maxwell-Boltzmann
b) the distribution function of the Fermi-Dirac
c) thermodynamic approach
d) the equations of quantum electronics

3. The work function of an electron from the metal surface is the difference between the energies:
a) the basic level and the Fermi level
b) the Fermi level and the surface level
c) the Fermi level and the vacuum level
d) the main level and the vacuum level

4. What is the equation of the law of thermionic emission is correct:
a)

b)

c)

d)

5. What is the width of the band gap in the metal cathode:
a) 0
b) 5
c) 10
d) ∞

6. What impact does electronegativity film covering a metal cathode, the work function:
a) no
b) the greater the work function, the more the value of electronegativity
c) the work function of the smaller, the more the value of electronegativity
d) the work function more in the absence of film on the surface of a metal cathode




7. As explained by the decrease in the work function in oxide cathodes:
a) forming sublevels permitted valence band
b) approved the formation of sub-levels in the band gap
c) forming sublevels permitted in the conduction band
d) the approach of the vacuum level to the conduction band

8. How are the laws of Stoletov and Einstein when considering photoelectron emission of metals:
a) nothing
b) exchange interactions occur between the metal atoms and wave packets
c) exchange interactions occur between the metal atoms and the total energy source
d) Only notation

9. What percentage of the emission of secondary electrons emitted from the metal compared to other neuprugootrazhennymi and uprugootrazhennymi primary electron emission:
a) 100%
b) 90%
c) 30%
d) 1%

10. What should be the value of the external electric field applied to the narrow section of the metal to observe field emission:
a) 10 / cm2
b) 107 / cm2
c) 103 / cm2
d) 100 / cm2

11. By reason limiting value occurs anode current in a vacuum diode as the electrons move from the cathode to the anode:
a) the absence of space charge
b) the presence of space charge
c) the speed of the emitted electrons from the cathode is zero
d) the speed of the electrons emitted from the cathode is not equal to zero

12. What physical quantities connects the second law of three
a) the anode current anode voltage
b) an anode current with dielectric
c) the anode current with the charge density
d) the anode current with the distance between the cathode and the anode,

13. What kind of expression is determined by the steepness of the vacuum diode:
a) b) c) d)






14. Which of the equations determine the static and dynamic characteristics of the transistor:

a) b)

c) d)

e) f)

15. Which transistor is used to:
a) for the current amplification
b) to increase the voltage
c) for power amplification
d) to increase the current, voltage, power,

16. What is the manifestation of dynatron effect tetrode:
a) the impact of a positive voltage on the control grid
b) the impact of a negative voltage on the control grid
c) sputtering of secondary electrons from the anode
d) an additional flight of ions from the cathode

17. The number of grids in tetrode:
a) 1
b) 2
c) 3
d) 4

18. In a sequence from the cathode to the anode mesh placed in a pentode:
a) K b) K c) K
Sus Ses Szasch
Ses Ses Szasch
Szasch Sousse Sousse
A A

19.

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Answers to test questions

Colloquium 2


1. What is the difference between convection and induced currents move a single electron in the electron-electron space:
a) there is no difference
b) in the value of the convection current
c) The magnitude of the induced current
d) they do not exist

2. What is the trajectory of charged particles in an electric field the following conditions:

1). E> 0, 2). E = 0 3). E <0
a) direct a) direct a) direct
b) spiral b) spiral b) spiral
c) trochoid c) trochoid c) trochoid
d) a parabola d) parabola d) parabola

3. What is the trajectory of the charged particle in a uniform magnetic field:
a) direct
b) spiral
c) trochoid
d) cycloid
e) a parabola

4. What is the trajectory of charged particles in crossed electric and magnetic fields:
a) direct
b) spiral
c) trochoid
d) cycloid
e) a parabola

5. Indicate the correct entry of the law of electronic optical refraction:

a) b)

c) d)

6. Specify the correct equation for the focal length of the spherical electrical double layer:

a) b)

c) d)
7. On what grounds are distinguished by magnetic electrostatic lens:
a) by the action of the lens on the electron velocity
b) by the action of the lens on the geometry of the motion of the electron beam
c) angularly deflecting the electron beam
d) there is no difference

8. Indicate the correct entry expression ionization coefficient Towns:

a) b)

c) d)

9. Due to some physical phenomena experimental gain power in the lamp discharge gap increase compared to the theoretical:
a) bombing of the gas atoms with neutrons
b) the influence of the outside temperature
c) the formation of additional charge carriers by ionization ion strikes
d) ion bombardment of the cathode

10. Which expression represents the condition of the discharge ignition (Paschen's law):

a) b)

c) d)

11. List the requirements for lamps intended for use in the microwave range:
a) to increase the angle of flight
b) to increase the inductance of the inputs of the electrodes in the lamp
c) to reduce the inductance of the electrodes in the lamp bushings
d) reduce the angle of flight
e) increase the distance between the electrodes lamps
f) to reduce the distance between the electrodes of the lamp


12. What is the physical meaning of time τ and θ the angle of flight of microwave electronic devices:
a) τ - time of flight of the electrons between the grid and the anode
b) τ - time of flight of the electrons between the anode and the cathode
c) θ - the angle of flight characteristic geometric deflection of the electron beam
d) θ - angle span characterizes the phase change of the voltage applied to the electrodes under consideration during the movement of electrons between these electrodes

13. How many cavities in the klystron, and what functions they perform:
a) one
b) Two
c) Three
d) four
e) for increasing the magnetic flux of electrons
f) to change the phase of the field
g) to modulate the electron beam velocity
h) for the selection of electromagnetic energy

14. How many resonators in a reflex klystron, and what functions they perform:
a) one
b) Two
c) Three
d) four
e) strengthening the movement of electrons in the cathode-anode space
f) deceleration of the electrons in the cathode-anode space
g) modulation of the electron velocity
h) modulation and selection of energy from electrons as they move from the reflector

15. Indicate the correct expression for the force acting on the electrons in crossed electric and magnetic fields:

a) b)

c) d)

16. How many resonator

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