59001. 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?
59002. Assertion (A): In design of circuit using BJT, a derating factor is used. Reason (R): As the ambient temperature increases, heat dissipation becomes slower.
59003. If the drift velocity of holes under a field gradient of 100 V/m is 5m/sec. Their mobility is
59004. In a P type silicon sample, the hole concentration is 2.25 x 1015 / cm3. If the intrinsic carrier concentration is 1.5 x 1010/ cm3 the electron concentration is
59005. The behaviour of a JFET is similar to that of
59006. What is the effect of cut in voltage on the wave form of output as compared to input in a semiconductor diode?
59007. As temperature increases the number of free electrons and holes in an intrinsic semiconductor
59008. At room temperature kT = 0.03 eV.
59009. Assertion (A): A JFET behaves as a resistor when VGS < VP. Reason (R): When VGS < VP, the drain current in a JFET is almost constant.
59010. In a reverse biased P-N junction, the current through the junction increases abruptly at
59011. Dielectric strength of polythene is around
59012. Resistivity of hard drawn copper is
59013. The channel of JFET consists of
59014. In a bipolar junction transistor a dc = 0.98, ICO= 2 μA and 1B = 15 μA. The collector current IC is
59015. The voltage across the secondary of the transformer in a half wave rectifier with a shunt capacitor filter is 50 volts. The maximum voltage that will occur on the reverse biased diode will be
59016. Assertion (A): The forward resistance of a p-n diode is not constant. Reason (R): The v-i characteristics of p-n diode is non-linear.
59017. For a photoengraving the mask used is
59018. In a varactor diode the increase in width of depletion layer results in
59019. In given figure a silicon diode is carrying a constant current of 1 mA. When the temperature of the diode is 20°C, VD is found to be 700 mV. If the temperature rises to 40°C, VD becomes approximately equal to
59020. The work function of a photo surface whose threshold wave length is 1200 A, will be
59021. The diameter of an atom is
59022. N-type silicon is obtained by doping silicon with
59023. When a p-n junction is reverse biased
59024. If a sample of germanium and a sample of Si have the impurity density and are kept at room temperature then
59025. When a large number of atoms are brought together to form a crystal
59026. Determine the transistor capacitance of a diffused junction varicap diode of a reverse potential of 4.2 V if C(0) = 80 pf and VT = 0.7 V
59027. At room temperature the barrier potential in a silicon diode is
59028. The cut in voltage of a diode is nearly equal to
59029. Assertion (A): In a BJT base current is very small. Reason (R): In a BJT recombination in base region is high.
59030. A reverse voltage of 18 V is applied to a semiconductor diode. The voltage across the depletion layer is
59031. As temperature increases the forbidden gap in silicon increases.
59032. Assertion (A): Germanium is more commonly used than silicon. Reason (R): Forbidden gap in germanium is less than that in silicon.
59033. Which of the following devices has substrate?
59034. Assertion (A): The amount of photoelectric emission depends on the intensity of incident light. Reason (R): Photo electric emission can occur only if frequency of incident light is less than threshold frequency.
59035. In degenerate p type semiconductor material, the Fermi level,
59036. 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.
59037. As comparated to an ordinary p-n diode, the extent of impurity atoms in a tunnel diode
59038. In active filter circuits, inductances are avoided mainly because they
59039. When a p-n-p transistor is operating in active region, the current in the n region is due to
59040. In a JFET
59041. Consider the following statements: The function of oxide layer in an IC device is to mask against diffusion or non implantinsulate the surface electricallyincrease the melting point of siliconproduce a chemically stable protective layer Of these statements:
59042. An extrinsic semiconductor sample has 6 billion silicon atoms and 3 million pentavalent impurity atoms. The number of electrons and holes is
59043. In a reverse biased p-n junction, the reverse bias is 4V. The junction capacitance is about
59044. Photoconductive devices uses
59045. Assertion (A): Oxide coated cathodes are very commonly used. Reason (R): Work function of oxide coated cathode is 1 eV whereas it is 4.5 eV for pure tungsten.
59046. A JFET operates in ohmic region when
59047. In CE connection, the leakage current of a transistor is about
59048. The early effect in a BJT is caused by
59049. If the sum of all forces acting on a body is zero,then the body may be in equilibrium provided the forces are
59050. Assertion (A): In active region of CE output characteristics of BJT, collector current is nearly constant. Reason (R): Base current in CE connection is very small.