Que- Which one of following postulate is in accordance with the Rutherfords model ?
a. continuous spectra for atoms
b. discrete spectra for atoms
c. either continuous nor discrete
d. no spectrum
Answer- continuous spectra for atoms
Que- Ground state energy of the 4th orbit in a H-atom is_____________?
a. 13.60 eV
b. 3.40 eV
c. 0.85 eV
d. 1.51 eV
Answer- 0.85 eV
Que- The electric P.E of an electron in an orbit at a distance rn from the positive charge_____________?
a. Ke2/rn
b. Ke2/rn2
c. ÀKe2/rn
d. ÀKe2/rn2
Answer- ÀKe2/rn
Que- Bracket series is obtained when all transition of electron terminate on_______________?
a. 4th orbit
b. 5th orbit
c. 3rd orbit
d. 2nd orbit
Answer- 4th orbit
Que- The penetrating power of X-rays depends on their______________?
a. applied voltage
b. frequency
c. source
d. all of the above
Answer- frequency
Que- Reverse process of photoelectric effect is_______________?
a. pair production
b. Compton effect
c. annihilation of matter
d. X-rays production
Answer- X-rays production
Que- Radiation with wavelength longer than red lights______________?
a. ultraviolet rays
b. X-rays
c. infra red radiation
d. visible radiation
Answer- infra red radiation
Que- In an electronic transition atom cannot emit______________?
a. γ-rays
b. Infra red radiation
c. Visible light
d. Ultraviolet rays
Answer- γ-rays
Que- X-rays are similar in nature to_______________?
a. Cathode rays
b. Positive rays
c. γ-rays
d. Beta rays
Answer- γ-rays
Que- When X-rays are passed through successive aluminum sheets what happens to their thickness ?
a. increases
b. it decreases
c. it remains same
d. sometimes increases and sometimes decreases
Answer- it remains same
Que- Quality of X-rays depends upon ____________ A-filament current B-accelerating voltage C-material of the target ?
a. A & B
b. B & C
c. A & C
d. A B & C
Answer- B & C
Que- In an X-ray tube electrons each of charge e are accelerated through V potential difference allowed to hit a metal target. The wavelength of the X-rays emitted is_______________?
a. he/ev
b. he/Vc
c. eV/h
d. impossible to predict
Answer- he/ev
Que- Radiation produced from TV picture tube is_____________?
a. B-rays
b. X-rays
c. Far infrared
d. Infrared
Answer- X-rays
Que- The minimum wavelength of X-rays can further be reduced by _______________?
a. Reducing the pressure or cooling the target
b. Increasing the temperature of the filament.
c. Using a target element of higher atomic number
d. Increasing the potential difference between the cathode and the target
Answer- Increasing the potential difference between the cathode and the target
Que- The characteristic X-rays spectrum is due to_____________?
a. The illumination of the target metal by ultra-violet radiation
b. The bombardment of the target by protons
c. The bombardment of target by electrons
d. The absorption of radiation by the target metal
Answer- The bombardment of target by electrons
Que- The minimum wavelength of X-rays produced by the bombardment of electrons on the screen of a television set where the accelerating potential is 2.0K V will be______________?
a. 6.2 x 10-10m
b. 9.1 x 10-18m
c. 3.11 x 10-10m
d. 4 x 10-10m
Answer- 6.2 x 10-10m
Que- Maximum frequency in the spectrum from X-ray tube is directly proportional to the______________?
a. Number of incident electron i.e. filament current
b. The kinetic energy of the incident electron i.e. the potential difference through which they are accelerated
c. The soft target which can easily emit electrons
d. All of above are correct
Answer- The kinetic energy of the incident electron i.e. the potential difference through which they are accelerated
Que- X-rays are diffracted by a crystal but not by a diffraction grating because_____________?
a. The ions in a crystal are well arranged
b. The lines in a diffraction grating cannot reflect X-rays.
c. The penetration power of X-rays is high in a diffraction grating
d. The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal
Answer- The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal
Que- UV radiation can be produced by______________?
a. Heating the filament
b. Electron excitation in the gas
c. Ionization of atoms
d. All the above
Answer- Electron excitation in the gas
Que- Wave-like characteristic of electron is demonstrated by______________?
a. Line spectrum of atoms
b. Production of x-rays.
c. Diffraction by crystalline solids
d. Photoelectric effect
Answer- Diffraction by crystalline solids
Que- Electron cannot exist in the nucleus it is confirmed by observing that______________?
a. It does emit radiation
b. Its size as compare to proton and neutron is very small
c. No antiparticle of electron is present
d. The velocity of electron must be very high according to uncertainty principle
Answer- The velocity of electron must be very high according to uncertainty principle
Que- In normal state of energy the incident high energy photons will be______________?
a. Stimulated
b. Absorbed
c. Cause X-ray emission
d. Cause laser production
Answer- Absorbed
Que- In laser production the state in which more atoms are in the upper state than in the lower one is called_____________?
a. Metal stable state
b. Normal state
c. Inverted population
d. All the above
Answer- Inverted population
Que- The metastable state for an atom in laser light is_____________?
a. 10-4 sec
b. 10-5 sec
c. 10-3 sec
d. 10-8 sec
Answer- 10-3 sec
Que- In He-Ne laser the lasing action is produced by_______________?
a. Ne only
b. He-Ne both
c. Electrons of He
d. Electrons Ne
Answer- Ne only
Que- Reflecting mirrors in laser is used to______________?
a. Further stimulation
b. Lasing more
c. For producing more energetic lasers
d. All
Answer- Further stimulation
Que- The velocity of laser light is___________________?
a. Less than ordinary light
b. More than ordinary light
c. Equal to ordinary light
d. Different for different colours or frequency
Answer- Equal to ordinary light
Que- Electrons present in p-type material due to thermal pair generation are_____________?
a. majority carriers
b. minority carriers
c. dual carriers
d. blockers
Answer- minority carriers
Que- Semi-conductor germanium and silicon are_________________?
a. pentavalent
b. trivalent
c. divalent
d. tetravalent
Answer- tetravalent
Que- p-n junction when reversed biased acts as a_______________?
a. capacitor
b. inductor
c. on switch
d. off switch
Answer- off switch
Que- In n-p-n transistor, p works as______________?
a. collector
b. emitter
c. base
d. any of above
Answer- base
Que- Identify the correct statement about minority carriers_____________?
a. holes in n-type and free electrons in p-type
b. holes in n-type and p-type
c. free electrons in n-type and holes in p-type
d. free electrons in n-type and p-type
Answer- holes in n-type and free electrons in p-type
Que- The velocity of an oscillating charge as it moves to and fro along a wire is always_____________?
a. constant
b. zero
c. changing
d. infinite
Answer- changing
Que- Which one of the following has the greatest energy gap ?
a. insulator
b. conductor
c. semi conductor
d. any of above
Answer- insulator
Que- Thermions are________________?
a. protons
b. positrons
c. electrons
d. photons
Answer- electrons
Que- In the transistor schematic symbol, the arrow_______________?
a. is located on the emitter
b. is located on the base
c. is locate on the collector
d. points form north to south
Answer- is located on the emitter
Que- The semiconductor diode can be used as a rectifier because _______________?
a. It has low resistance to the current flow when forward biased & high resistance when reverse biased.
b. It has low resistance to the current flow when forward biased.
c. It has high resistance to the current flow when reverse biased
d. Its conductivity increases with rise of temperature.
Answer- It has low resistance to the current flow when forward biased & high resistance when reverse biased.
Que- The device or circuit used for conversion of A.C. into D.C. is called_______________?
a. An amplifier.
b. A rectifier
c. Filtering circuit
d. Converter.
Answer- A rectifier
Que- The especially designed semiconductor diodes used as indicator lamps in electronic circuits are___________?
a. The switch
b. The light emitting diode
c. The photo diodes
d. Solar cells.
Answer- The light emitting diode
Que- Semi-conductors with donor atoms and free electrons belong to the type________________?
a. n
b. p
c. mix
d. any of above
Answer- n
Que- In p-n-p transistor the collector current is________________?
a. equal to emitter current
b. slightly less than emitter current
c. greater than emitter current
d. any of above
Answer- slightly less than emitter current
Que- The simplest type of rectification known as half wave rectification is obtained by____________________?
a. using a transistor
b. suppressing the harmonics in A.C voltage
c. suppressing half wave of A.C supply by using diode
d. using a Coolidge tube
Answer- suppressing half wave of A.C supply by using diode
Que- Depletion region of a junction is formed_____________?
a. during the manufacturing process
b. under forward bias
c. under reverse bias
d. when temperature varies
Answer- during the manufacturing process
Que- Which one of following band is completely filled in case of conductors ?
a. Conduction band
b. Fermi band
c. Valence band
d. Forbidden band
Answer- Conduction band
Que- The value of resistivity for insulator is of the order of____________?
a. 105 ohm metre
b. 106 ohm metre
c. 107 ohm metre
d. 108 ohm metre
Answer- 108 ohm metre
Que- Forward current through a semi conductor diode circuit is due to____________?
a. minority carriers
b. majority carriers
c. holes
d. electron
Answer- majority carriers
Que- Which one of the following is not a donor impurity ?
a. antimony
b. phosphorus
c. aluminium
d. arsenic
Answer- aluminium
Que- In the transistor schematic symbol, the arrow______________?
a. is located on the emitter
b. is located on the base
c. is locate on the collector
d. points form north to south
Answer- is located on the emitter
Que- In full wave rectification the output D.C. voltage across the load is obtained for_____________?
a. The positive half cycle of input A.C.
b. The negative half cycle of input A.C
c. The complete cycle of input A.C
d. All of the above.
Answer- The complete cycle of input A.C
Que- In half-wave rectification the output D.C voltages is obtained across the load for_______________?
a. The negative half cycle of A.C
b. The positive half cycle of A.C
c. The positive and negative half cycles
d. Either positive or negative half of A.C.
Answer- The positive half cycle of A.C.
Que- The device used for conversion of D.C to A.C is called______________?
a. Converter
b. A rectifier
c. Inverter
d. Oscillator
Answer- Inverter
Que- The specially designed semi-conductor diodes used as fast counters in electronic circuits are______________?
a. The light emitting diodes
b. Photo diodes
c. Photo voltaic cell
d. Solar cells.
Answer- Photo diodes
Que- The alternating voltage is an example of_______________?
a. A digital waveform
b. An analogue waveform
c. Discrete waveform
d. None at all
Answer- An analogue waveform
Que- The operational amplifier is______________?
a. A high gain amplifier
b. A high-power amplifier
c. A high resistance amplifier
d. A low resistance amplifier
Answer- A high gain amplifier
Que- To obtain an n-type semiconductor germanium crystal it must be doped with foreign atoms whose valency is_____________?
a. 2
b. 3
c. 4
d. 5
Answer- 5
Que- The operation of a transistor requires______________?
a. That the emitter be heated
b. That the base be heated
c. That the collector be heated
d. None of the above
Answer- None of the above
Que- Non-inverting amplifier circuits have____________?
a. A very high input impedance
b. A very low input impedance
c. A low output impedance
d. None of the above
Answer- A very high input impedance
Que- An OP-AMP comparator is a circuit that compares the signal voltage on one of its inputs with a ______________?
a. Non-inverting voltage at output
b. Reference voltage on the other
c. Virtual input
d. Output
Answer- Reference voltage on the other
Que- The working of transistor as amplifier is similar to________________?
a. Step up transformer
b. Step down transformer
c. Three diodes in common
d. Triode vacuum tube
Answer- Triode vacuum tube
Que- To obtain a p-type semi-conductor Si Crystal must be doped with foreign atoms whose valency is_____________?
a. 2
b. 3
c. 4
d. 5
Answer- 3
Que- In a half-wave rectifier the r.m.s. value of the A.C component of the wave is________________?
a. Equal to D.C value
b. More than D.C value
c. Less than D.C value
d. Zero
Answer- More than D.C value
Que- In forward bias the width of potential barrier_____________?
a. Increases
b. Decreases
c. Remains same
d. No effect
Answer- Decreases