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

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

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India’s No 1IES AcademyIES-2010ET (Paper-I)(c) Increases at low values of electric field and decreases at high values of electricfield exhibiting negative differential resistance(d) Increases linearly with electric field at low values of electric field and graduallysaturates at higher values of electric fieldQ66. The diffusion potential across a P-N junction(a) Decreases with increasing doping concentration(b) Increases with decreasing band gap(c) Does not depend on doping concentration(d) Increases with increase in doping concentrationQ67. The break down voltage of a transistor with its base open is BVCEO and thatwith emitter open is BVCBO, then(a) BVCEO = BVCBO(b) BVCEO > BVCBO(c) BVCEO < BVCBO(d) BVCEO is not related to BVCBO.Q68. In a P type silicon sample, the hole concentration is 2.25 × 10 15 /cm 3 . If theintrinsic carrier concentration is 1.5 × 10 10 /cm 3 , the electron concentrationis(a) zero (b) 10 10 /cm 3 (c) 10 5 /cm 3 (d) 1.5 × 10 25 /cm 3Q69. In the transistor circuit shown in Figure below, collector-to-ground voltageis + 20 V. Which of the following is the probable cause of error?(a) Collector-emitter terminals shorted(b) Emitter to ground connection open(c) 10 kΩ resistor open(d) Collector-base terminals shortedQ70. The static characteristic of an adequately forward biased p-n junction is astraight line, if the plot is of(a) log I vs. log V (b) log I vs. V (c) I vs. log V (d) I vs. VQ71. For a MOS capacitor fabricated on a p-type semiconductor, strong inversionoccurs when(a) Surface potential is equal to Fermi potential(b) Surface potential is zero(c) Surface potential is negative and equal to Fermi potential in magnitude(d) Surface potential is positive and equal to twice the Fermi potential.Q72. The probability that an electron in a metal occupies the Fermi-level, at anytemperature (> 0 K)(a) 0 (b) 1 (c) 0.5 (d) 1.5www.iesacademy.com Email: iesacademy@yahoo.com Page-12__25, 1 st Floor, Jia Sarai, Near IIT. New Delhi-16 Ph: 011-26537570, 9810958290

India’s No 1IES AcademyIES-2010ET (Paper-I)Q73. A transistor having α = 0.99 and VBE= 0.7 V is used in the circuit shownin Figure. The value of the collectorcurrent will be .(a) 1.39 mA (b) 3.7 mA(c) 5.33 mA (d) 7.73 mAQ74. An n-p-n transistor under forward-active mode of operation is biased at IC =1 mA, and has a total emitter-base capacitance C π of 12 pF, and the basetransit time τ Fof 260 psec. Under this condition, the depletion capacitanceof the emitter-base junction is .[use VT. 26mV](a) 2pF (b) 3pF (c) 4pF (d) 6pFQ75. The units of q/kT are(a) V(b)1V − (c) J (d) J/KQ76. An n channel JFET has IDSS = 1 mA and Vp = -5 V. The maximum transconductanceis .(a)0.2m (b)0.4m (c)0.6m (a)0.8mQ77. The three values of a one-dimensional potential function φ shown in the givenFigure and satisfying Laplace equation are related aswww.iesacademy.com Email: iesacademy@yahoo.com Page-13__2φ + φ 2φ + φ 2φ + 2φ φ + 3φφ = φ = φ = φ =3 3 3 2( a) ( b) ( c) ( d)3 1 1 3 1 3 1 32 2 2 2Q78. The electric field of a uniformplane wave is givenby8E = 10cos( 3π×10 t−πz)axMatch List I with List II pertaining to the above wave and select the correctanswer using the codes given below the lists:List IList II(Parameters)(Values in MKS units)A. Phase velocity 1. 2B. Wavelength 2. 3.14C. Frequency 3. 377D. Phase constant 4. 1.5 × 10 85. 3.0 × 10 8Codes:A B C D A B C D25, 1 st Floor, Jia Sarai, Near IIT. New Delhi-16 Ph: 011-26537570, 9810958290

India’s No 1<strong>IES</strong> <strong>Academy</strong><strong>IES</strong>-<strong>2010</strong><strong>ET</strong> (<strong>Paper</strong>-I)(c) Increases at low values of electric field and decreases at high values of electricfield exhibiting negative differential resistance(d) Increases linearly with electric field at low values of electric field and graduallysaturates at higher values of electric fieldQ66. The diffusion potential across a P-N junction(a) Decreases with increasing doping concentration(b) Increases with decreasing band gap(c) Does not depend on doping concentration(d) Increases with increase in doping concentrationQ67. The break down voltage of a transistor with its base open is BVCEO and thatwith emitter open is BVCBO, then(a) BVCEO = BVCBO(b) BVCEO > BVCBO(c) BVCEO < BVCBO(d) BVCEO is not related to BVCBO.Q68. In a P type silicon sample, the hole concentration is 2.25 × 10 15 /cm 3 . If theintrinsic carrier concentration is 1.5 × 10 10 /cm 3 , the electron concentrationis(a) zero (b) 10 10 /cm 3 (c) 10 5 /cm 3 (d) 1.5 × 10 25 /cm 3Q69. In the transistor circuit shown in Figure below, collector-to-ground voltageis + 20 V. Which of the following is the probable cause of error?(a) Collector-emitter terminals shorted(b) Emitter to ground connection open(c) 10 kΩ resistor open(d) Collector-base terminals shortedQ70. The static characteristic of an adequately forward biased p-n junction is astraight line, if the plot is of(a) log I vs. log V (b) log I vs. V (c) I vs. log V (d) I vs. VQ71. For a MOS capacitor fabricated on a p-type semiconductor, strong inversionoccurs when(a) Surface potential is equal to Fermi potential(b) Surface potential is zero(c) Surface potential is negative and equal to Fermi potential in magnitude(d) Surface potential is positive and equal to twice the Fermi potential.Q72. The probability that an electron in a metal occupies the Fermi-level, at anytemperature (> 0 K)(a) 0 (b) 1 (c) 0.5 (d) 1.5www.iesacademy.com Email: iesacademy@yahoo.com Page-12__25, 1 st Floor, Jia Sarai, Near IIT. New Delhi-16 Ph: 011-26537570, 9810958290

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