1. Electronics is the branch of engineering which deals with flow of electrons through
a) semiconductor
b) gas
c) vaccum
d) all of these
ans. d
2. The liberation of electrons from the surfaces of a substance is called
a) bombardment of electrons
b) electronic emission
c) movement of free electrons
d) ions emission
ans. b
3. The metal from which the electrons are emitted is called
a) an emitter
b) a cathode
c) an emitter or a cathode
d) none of these
ans. c
4. An emitter is generally called
a) anode
b) cathode
c) grid
d) drain
ans. b
5. Oxide-coated cathode is used in
a) low power tubes
b) medium power tubes
c) high power tubes
d) medium and high power tubes
ans. a
6. The emitter must have the following characteristics:
a) high melting point
b) low value of work function
c) immunity to reaction from residual gasses and water vapours
d) All of these
ans. d
7. In an indirectly heated cathodes
a) filament is not used
b) filament heater is used
c) filament heater may or may not be used
d) high voltage is used
ans. b
8. An electron tube can only operate when
a) anode is negative with respect to cathode
b) anode is positive with respect to cathode
c) anode must be at zero potential with respect to cathode
d) anode must be earthed
ans. b
9. The work function of metal is generally expressed is
a) joules
b) volts
c) electrons
d) electron volt
ans. d
10. The process of conversion ac into dc is called
a) amplification
b) modulation
c) rectification
d) factorization
ans. c
a) semiconductor
b) gas
c) vaccum
d) all of these
ans. d
2. The liberation of electrons from the surfaces of a substance is called
a) bombardment of electrons
b) electronic emission
c) movement of free electrons
d) ions emission
ans. b
3. The metal from which the electrons are emitted is called
a) an emitter
b) a cathode
c) an emitter or a cathode
d) none of these
ans. c
4. An emitter is generally called
a) anode
b) cathode
c) grid
d) drain
ans. b
5. Oxide-coated cathode is used in
a) low power tubes
b) medium power tubes
c) high power tubes
d) medium and high power tubes
ans. a
6. The emitter must have the following characteristics:
a) high melting point
b) low value of work function
c) immunity to reaction from residual gasses and water vapours
d) All of these
ans. d
7. In an indirectly heated cathodes
a) filament is not used
b) filament heater is used
c) filament heater may or may not be used
d) high voltage is used
ans. b
8. An electron tube can only operate when
a) anode is negative with respect to cathode
b) anode is positive with respect to cathode
c) anode must be at zero potential with respect to cathode
d) anode must be earthed
ans. b
9. The work function of metal is generally expressed is
a) joules
b) volts
c) electrons
d) electron volt
ans. d
10. The process of conversion ac into dc is called
a) amplification
b) modulation
c) rectification
d) factorization
ans. c
