NTA UGC NET/JRF Exam, June -2020 (Electronic Science)

Charge Couple Device (CCD) can be used either as an image sensor or as a shift register. As a photo detector it has also been called chargecoupled image sensor or charge-transfer image sensor. Most common area images use either interline transfer or frame transfer readout architecture. The spacing between CCDs should be small for efficient charge transfer.
Which semi conductor materials are used to make Charge Couple Device (CCD)?
(a) Si
(b) Hg Cd Tc
(c) Ta
(d) In Sb
Choose the correct answer from the options given below:

Statement I: The advantage of frame transfer readout architecture, compared to the interline, transfer is a more efficient light - sensing area.
Statement II: For both interline transfer and frame-transfer, all columns advance their charge signals to the horizontal output register simultaneously.

In the light of the above statements, choose the most appropriate answer from the options given below:

Statement I: A line imager with dual output registers has poor read - out speed.
Statement II: In the frame transfer scheme, signals are shifted to a storage area away from the sensing area.

In the light of the above statements, choose the correct answer from the options given below:

Statement I: The three basic charge - transfer mechanisms in CCD are (a) thermal diffusion, (b) self- induced drift and (c) fringing- field effect.
Statement II: For small amount of signal charge, self induced drift is the dominant factor and for a reasonably large charge packet; thermal diffusion is the dominant transfer mechanism
In the light of the above statements, choose the most appropriate answer from the options given below:

The ability of the oscillator circuit is to oscillate at one exact frequency is called frequency stability, The frequency of oscillation is an important criterion. Usually the circuits producing sine waves are called oscillators while those generating a square wave, triangular wave and/or saw tooth wave are called generators though both of these can be used interchangeably.
Which of the following statements are not correct?
(a) Rise time of triangular waveform is always equal to its fall time
(b) Saw tooth waveforms have unequal rise and fall times
(c) Triangular wave generator can not be converted into a sawtooth wave generator
(d) Triangular wave generator can be converted into sawtooth wave generator by injecting a variable dc voltage into the inverting terminal of the integrator.
Choose the correct answer from the options given below: