IES-2010 IES Academy ET (Paper-I) Electronics Engineering (Paper-I)

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India’s No 1IES AcademyIES-2010Q51. The voltage V in Figure is always equal toET (Paper-I)(a) 9 V(b) 5 V(c) 1 V(d) None of the aboveQ52. In the circuit of Figure, the energy absorbed by the 4 Ω resistor in the timeinterval (0, ∞) is(a) 36 joules(b) 16 joules(c) 256 joules(d) None of the aboveQ53. In the circuit of Figure, the equivalent impedance seen across terminals a, bis(a) (16/3) Ω(b) (8/3) Ω(c) (8/3 + 12j) Ω(d) None of the aboveQ54. In the circuit of Figure, the current i Dthrough the ideal diode (zero cut involtage and zero forward resistance) equals(a) 0 A(b) 4 A(c) 1 A(d) None of the aboveQ55. The Hall angle θ of a metal sample is(a) Independent of the magnetic flux density B(b) Independent of the carrier mobility(c) Independent of the density of free carriers(d) Dependent on magnetic flux density, carrier mobility and density of free carriersQ56. The relaxation time (τ) in a perfect dielectric is(a) 0 (b) 1 (c) 1< τ < ∞ (d) ∞Q57. The conductivity of a metal at ultraviolet frequency (10 14 Hz) approximatelyequals(a) Infinity (b) Zero (c) DC conductivity (d) Half of DC conductivitywww.iesacademy.com Email: iesacademy@yahoo.com Page-10__25, 1 st Floor, Jia Sarai, Near IIT. New Delhi-16 Ph: 011-26537570, 9810958290
India’s No 1IES AcademyIES-2010Q58. Constantan is an alloy composed of(a) 86% copper, 12% manganese and 2% nickel(b) 76% nickel, 21% chromium, 2% manganese and 1% iron(c) 60% copper and 40% nickel(d) 40% copper, 40% nickel and 20% carbonET (Paper-I)Q59. Assuming carrier mobility to be temperature independent, it can be shownthat pure Si(Eg = 1.1eV) and Ge (Eg = 0.7eV) have the same conductivity at atemperature of(a) 191 K (b) 300 K (c) 471 K (d) 1470 KQ60. If the lattice temperature is increased then the Hall coefficient of asemiconductor will(a) Decrease(b) Increase(c) First increase to a peak and then decrease (d) Remain constantQ61. The decreasing order of the electrical resistivities of nichrome, silicon anddiamond is(a) Nichrome, silicon, diamond (b) Silicon, diamond, nichrome(c) Diamond, nichrome, silicon (d) Diamond, silicon, nichromeQ62. An n-channel silicon (Eg = 1.1 eV) MOSFET was fabricated using n + polysilicongate and the threshold voltage was found to be 1 V. Now, if the gateis changed to p + poly-silicon, other things remaining the same, the newthreshold voltage should be(a) -0.1 V (b) 0 V (c) 1.0 V (d) 2.1VQ63. A silicon nMOSFET has a threshold voltage of 1 V and oxide thickness ofo400 A [εr(SiO2) = 3.9, εo = 8.854 × 10 -14 F/cm, q = 1.6 × 10 -19 C]. The regionunder the gate is ion implanted for threshold voltage tailoring. The doseand type of the implant (assumed to be a sheet charge at the interface)required shifting the threshold voltage to - 1 V are(a) 1.08 × 10 12 /cm 2 , p – type(b) 1.08 × 10 12 /cm 2 , n – type(c) 5.4 × 10 11 /cm 2 , p – type(d) 5.4 × 10 11 /cm 2 , n –typeQ64. A Zener diode in the circuit shown in Figure has a knee current of 5 mA,and a maximum allowed power dissipation of 300 mW. What are theminimum and maximum load currents that can be drawn safely from thecircuit, keeping the output voltage Vo constant at 6 V?(a) 0 mA, 180 mA(b) 5 mA, 110 mA(c) 10 mA, 55 mA(d) 60 mA, 180 mAQ65. The drift velocity of electrons, in silicon,(a) Is proportional to the electric field for all values of electric field(b) Is independent of the electric fieldwww.iesacademy.com Email: iesacademy@yahoo.com Page-11__25, 1 st Floor, Jia Sarai, Near IIT. New Delhi-16 Ph: 011-26537570, 9810958290
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IES-2010 IES Academy ET (Paper-I) Electronics Engineering (Paper-I)

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