Q. If ib is plate current, eb is plate voltage and ec is grid voltage the v-i curve of a vacuum triode is ib = 0.003 (eb + kec)ⁿ. Typical values of k and n are

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Q. Electrons can be emitted from a metal surface due to high electric field.

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Q. In an n type semiconductor the fermi level is 0.35 eV below the conduction band, the concentration of donor atoms is increased to three times. The new position of Fermi level will be

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Q. Assertion (A): In a BJT, the base region is very thick.

Reason (R): In p-n-p transistor most of holes given off by emitter diffuse through the base.

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Q. Assertion (A): The behaviour of FET is similar to that of a pentode.

Reason (R): FETs and vacuum triode are voltage controlled devices.

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Q. SCR can be turned on by

1. applying anode voltage at a sufficient fast rate
2. applying sufficiently large anode voltage
3. increasing the temperature of SCR to a sufficiently
4. applying sufficiently large gate current

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Q. When a diode is not conducting, its bias is

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Q. The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply of frequency of

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Q. The number of valence electrons in a donor atom is

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Q. An electron rises through a voltage of 100 V. The energy acquired by it will be

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Q. Measurement of hall coefficient enables the determination of

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Q. Which of these has 3 layers?

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Q. For an P-channel enhancement type MOSFET determine the drain current if K = 0.278 x 10¯³A/V², VGS = -4V, VT = -2V, Voltage equivalent at 27°C = 26 mV.

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Q. The skin depth of copper is found to be 66 mm at 1 MHz at a certain temperature. At the same temperature and at 2 MHz, the skin depth would be approximately

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Q. When p-n junction is reverse biased the holes in p material move towards the junction and electrons in n material move away from the junction.

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Q. In which material do conduction and valence bands overlap

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Q. For a photoconductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in illumination results in

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Q. The number of p-n junctions in a semiconductor diode are

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Q. Assertion (A): A high junction temperature may destroy a diode.

Reason (R): As temperature increases the reverse saturation current increases.

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Q. A Si sample is doped with a fixed number of group N impurities. The electron density n is measured from 4 K to 1200 k for the sample. Which one of the following is correct?

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