58951. A semiconductor diode is biased in forward direction and carrying current I. The current due to holes in p material is
58952. Between which regions does BJT act like switch?
58953. Assertion (A): When a photoconductive device is exposed to light, its bulk resistance increases. Reason (R): When exposed to light, electron hole pairs are generated in the photoconductive device.
58954. Which of the following elements act as donor impurities? GoldPhosphorusBoronAntimonyArsenicIndium Select the answer using the following codes :
58955. Light dependent resistor is
58956. The breakdown voltage in a zener diode
58957. A varactor diode is used for
58958. One eV = 1.602 x 10-19 joules.
58959. Assertion (A): When VDS is more than rated value the drain current in a JFET is very high. Reason (R): When VDS is more than rated value, avalanche breakdown occurs.
58960. 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
58961. In which material do conduction and valence bands overlap
58962. For a photoconductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in illumination results in
58963. Discrete transistors T1 and T2 having maximum collector current rating of 0.75 amp are connected in parallel as shown in the figure, this combination is treated as a single transistor to carry a total current of 1 ampere, when biased with self bias circuit. When the circuit is switched on, T1 draws 0.55 amps and T2 draws 0.45 amps. If the supply is kept on continuously, ultimately it is very likely that
58964. The number of p-n junctions in a semiconductor diode are
58965. Assertion (A): A high junction temperature may destroy a diode. Reason (R): As temperature increases the reverse saturation current increases.
58966. When a diode is not conducting, its bias is
58967. The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply of frequency of
58968. The number of valence electrons in a donor atom is
58969. An electron rises through a voltage of 100 V. The energy acquired by it will be
58970. Which of the following lines is a part of dimension?
58971. A Varactor diode has
58972. The most important set of specifications of transformer oil includes
58973. Assertion (A): In Hall effect the O.C. transverse voltage developed by a current carrying semiconductor with a steady magnetic field perpendicular to the current direction has opposite signs for n and p semiconductors. Reason (R): The magnetic field pushes both holes and electrons in the same direction.
58974. A voltage of 9 V is applied in forward direction to a semiconductor diode in series with a load resistance of 1000 Ω. The voltage across the load resistance is zero. It indicates that
58975. If the drift velocity of holes under a field gradient of 100 V/m in 5 m/s, their mobility (in SI units) is
58976. The derating factor for a BJT transistor is about
58977. An intrinsic silicon sample has 2 million free electrons. The number of holes in the sample is
58978. Assertion (A): When reverse voltage across a p-n junction is increased, the junction capacitance decreases. Reason (R): Capacitance of any layer is inversely proportional to thickness.
58979. In an n type semiconductor
58980. Mobility of electrons and holes are equal.
58981. Electrons can be emitted from a metal surface due to high electric field.
58982. 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
58983. 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.
58984. Assertion (A): The behaviour of FET is similar to that of a pentode. Reason (R): FETs and vacuum triode are voltage controlled devices.
58985. SCR can be turned on by applying anode voltage at a sufficient fast rateapplying sufficiently large anode voltageincreasing the temperature of SCR to a sufficientlyapplying sufficiently large gate current.
58986. In a bipolar transistor
58987. If for a silicon n-p-n transistor, the base to emitter voltage (VBE) is 0.7 V and the collector to base voltage VCB is 0.2 Volt, then the transistor is operating in the
58988. The number of doped regions in a bipolar junction transistor is
58989. Donor energy level is n type semiconductor is very near valence band.
58990. GaAs has an energy gap 1.43 eV the optical cut off wavelength of GaAs would lie in the
58991. Which of the following is basically a voltage controlled capacitance?
58992. When the i-v curve of a photodiode passes through origin the illumination is
58993. An n type silicon bar 0.1 cm long and 100 μm2 in cross-sectional area has a majority carrier concentration of 5 x 1020/m3 and the carrier mobility is 0.13 m0/V-s at 300k. If the charge of an electron is 1.6 x 10-19 coulomb, then the resistance of the bar is
58994. The threshold voltage of a MOSFET can be lowered by using thin gate oxidereducing the substrate concentrationincreasing the substrate concentration. Of the above statement
58995. In which device does the extent of light controls the conduction
58996. An increase in junction temperature of a semiconductor diode
58997. An air gap provided in the iron core of an inductor prevents
58998. Generally, the gain of a transistor amplifier falls at high frequency due to the
58999. Which of these has a layer of intrinsic semiconductor?
59000. Assertion (A): When Diode used as rectifier the reverse breakdown voltage should not be exceeded. Reason (R): A high inverse voltage can destroy a p-n junction.