MCQOPTIONS
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MCQOPTIONS
This section includes 100 Mcqs, each offering curated multiple-choice questions to sharpen your Graduate Aptitude Test (GATE) knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
For a system to work, as oscillator the total phase shift of the loop gain must be equal to |
| A. | 90° |
| B. | 45° |
| C. | 270° |
| D. | 360° |
| Answer» E. | |
| 52. |
In a CE amplifier the input impedance is equal to the ratio of |
| A. | ac base voltage to ac base current |
| B. | ac base voltage to ac emitter current |
| C. | ac emitter voltage to ac collector current |
| D. | ac collector voltage to ac collector current |
| Answer» B. ac base voltage to ac emitter current | |
| 53. |
To protect the diodes in a rectifier and capacitor input filter circuit it is necessary to use |
| A. | surge resistor |
| B. | surge inductor |
| C. | surge capacitor |
| D. | both (a) and (b) |
| Answer» B. surge inductor | |
| 54. |
In a BJT circuit a pnp transistor is replaced by npn transistor. To analyse the new circuit |
| A. | all calculations done earlier have to be repeated |
| B. | replace all calculated voltages by reverse values |
| C. | replace all calculated currents by reverse values |
| D. | replace all calculated voltages and currents by reverse values |
| Answer» E. | |
| 55. |
If an amplifier with gain of - 1000 and feedback factor β = - 0.1 had a gain change of 20% due to temperature, the change in gain of the feedback amplifier would be |
| A. | 10% |
| B. | 5% |
| C. | 0.2% |
| D. | 0.01% |
| Answer» D. 0.01% | |
| 56. |
The load impedance ZL of a CE amplifier has R and L in series. The phase difference between output and input will be |
| A. | 180° |
| B. | 0 |
| C. | more than 90° but less than 180° |
| D. | more than 180° but less than 270° |
| Answer» E. | |
| 57. |
An RC coupled amplifier has an open loop gain of 200 and a lower cutoff frequency of 50 Hz. If negative feedback with β = 0.1 is used, the lower cut off frequency will be |
| A. | about 50 Hz |
| B. | about 5 Hz |
| C. | about 2.38 Hz |
| D. | about 70.5 Hz |
| Answer» D. about 70.5 Hz | |
| 58. |
For a base current of 10 μA, what is the value of collector current in common emitter if βdc = 100 |
| A. | 10 μA |
| B. | 100 μA |
| C. | 1 mA |
| D. | 10 mA |
| Answer» D. 10 mA | |
| 59. |
To prevent a DC return between source and load, it is necessary to use |
| A. | resistor between source and load |
| B. | inductor between source and load |
| C. | capacitor between source and load |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 60. |
As per BIS there are 6 accuracy classes of instruments. |
| A. | True |
| B. | False |
| Answer» C. | |
| 61. |
Assertion (A): When a wattmeter is used for low impedance loads, the pressure coil is connected across the load. Reason (R): A wattmeter measures apparent power. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true R is false |
| D. | A is false R is true |
| Answer» D. A is false R is true | |
| 62. |
An LVDT is used to measure displacement. The LVDT feeds a Voltmeter of 0-5 V range through a 250 gain amplifier. For a displacement 0.5 mm the output of LVDT is 2 mV. The sensitivity of instrument is |
| A. | 0.1 V/mm |
| B. | 0.5 V/mm |
| C. | 1 V/mm |
| D. | 5 V/mm |
| Answer» D. 5 V/mm | |
| 63. |
A piezoelectric force transducer has a charge sensitivity of 20 pC/N. It is connected to a charge amplifier and overall gain of transducer and amplifier is 50 mV/N. The gain of amplifier is |
| A. | 1 mV/pC |
| B. | 1.5 mV/pC |
| C. | 2.5 mV/pC |
| D. | 4 mV/pC |
| Answer» D. 4 mV/pC | |
| 64. |
A moving coil instrument has a resistance of 0.6 Ω and full scale deflection at 0.1 A. To convert it into an ammeter of 0-15 A range, the resistance of shunt should be |
| A. | 0.6 Ω |
| B. | 0.06 Ω |
| C. | 0.1 Ω |
| D. | 0.004 Ω |
| Answer» E. | |
| 65. |
In which of the transformer is the secondary nearly short circuited under normal operating conditions? |
| A. | CT |
| B. | PT |
| C. | Distribution transformer |
| D. | Power transformer |
| Answer» B. PT | |
| 66. |
Assertion (A): De sauty's bridge is suitable only for pure capacitor. Reason (R): Capacitors are mostly perfect. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true R is false |
| D. | A is false R is true |
| Answer» D. A is false R is true | |
| 67. |
A single phase energy meter has the rating 1200 resolutions/ kWh. If a 500 W electric gadget is used for 4 hours, the energy meter will make |
| A. | 1200 revolutions |
| B. | 1800 revolutions |
| C. | 2100 revolutions |
| D. | 2400 revolutions |
| Answer» E. | |
| 68. |
Which of the following voltmeters would you use for measuring voltage across 20 kΩ resistance? |
| A. | Voltmeter having a resistance of 5 kΩ |
| B. | Voltmeter having a sensitivity of 1 kW/V |
| C. | Voltmeter having sensitivity of 10 kW/V |
| D. | None of the above |
| Answer» D. None of the above | |
| 69. |
In a CRO which of the following is not a part of electron gun |
| A. | cathode |
| B. | grid |
| C. | accelerating anode |
| D. | X - Y plates |
| Answer» E. | |
| 70. |
In 3 phase power measurement by two wattmeter method, the reading of one wattmeter is zero. The power factor of load is |
| A. | 1 |
| B. | 0.5 |
| C. | 0 |
| D. | 0.8 |
| Answer» C. 0 | |
| 71. |
The coil of a moving iron instrument has a resistance of 500 Ω and an inductance of 1 H. It reads 250 V when a 250 V dc is applied. If series resistance is 2000 Ω, its reading when fed by 250 V, 50 Hz ac will be |
| A. | 260 V |
| B. | 252 V |
| C. | 250 V |
| D. | 248 V |
| Answer» E. | |
| 72. |
An ammeter of 0-25 A range has a guaranteed accuracy of 1% of full scale reading. The current measured is 5 A. The limiting error is |
| A. | 2% |
| B. | 2.5% |
| C. | 4% |
| D. | 5% |
| Answer» E. | |
| 73. |
To increase Q factor of a coil, the wire should be |
| A. | long |
| B. | thin |
| C. | thick |
| D. | long and thin |
| Answer» D. long and thin | |
| 74. |
The synthesis of minimum function was suggested by |
| A. | OBrune |
| B. | R. Richards |
| C. | Bott and Duffin |
| D. | none of the above |
| Answer» B. R. Richards | |
| 75. |
A cable has an insulation resistance of 1010 ohms. If the length is doubled, the insulation resistance will be |
| A. | 2 x 1010 Ω |
| B. | 0.5 x 1010 Ω |
| C. | 1010 Ω |
| D. | 4 x 1010 Ω |
| Answer» C. 1010 Ω | |
| 76. |
A 0.5 μF capacitor is connected across a 10 V battery. After a long time, the circuit current and voltage across capacitor will be |
| A. | 0.5 A and 0 V |
| B. | 0 A and 10 V |
| C. | 20 A and 5 V |
| D. | 0.05 A and 5 V |
| Answer» C. 20 A and 5 V | |
| 77. |
A capacitor stores 0.15C at 5 V. Its capacitance is |
| A. | 0.75 F |
| B. | 0.75 μF |
| C. | 0.03 F |
| D. | 0.03 μF |
| Answer» D. 0.03 μF | |
| 78. |
A series RC circuit has R = 5 Ω and C = 10 μF. The current in the circuit is 5 sin 20000t. The applied voltage is |
| A. | 252 sin (20000t + 45°) |
| B. | 252 sin (20000t - 45°) |
| C. | 252 sin 20000t |
| D. | 252 sin (20000t - 90°) |
| Answer» C. 252 sin 20000t | |
| 79. |
Wave A = 100 sin ωt and wave B = 100 cos ωt. Then |
| A. | rms values of the two waves are equal |
| B. | rms values of A is more than that of B |
| C. | rms values of A is less than that of B |
| D. | rms values of the two waves may or may not be equal |
| Answer» B. rms values of A is more than that of B | |
| 80. |
The drift velocity of electrons is |
| A. | very small as compared to speed of light |
| B. | equal to speed of light |
| C. | almost equal to speed of light |
| D. | half the speed of light |
| Answer» B. equal to speed of light | |
| 81. |
The terms RMS and average values apply only to sine waves. |
| A. | True |
| B. | False |
| Answer» C. | |
| 82. |
For a transmission line open circuit and short circuit impedances are 20 Ω and 5 Ω. Then characteristic impedance is |
| A. | 100 Ω |
| B. | 100 Ω |
| C. | 25 Ω |
| D. | 10 Ω |
| Answer» E. | |
| 83. |
n a minimum function |
| A. | the degree of numerator and denominator are equal |
| B. | the degree of numerator and denominator are unequal |
| C. | the degree of numerator is one more than degree of denominator |
| D. | the degree of numerator is one less than degree of denominator |
| Answer» B. the degree of numerator and denominator are unequal | |
| 84. |
Henry is equivalent to |
| A. | Volts/Ampere |
| B. | Weber/Volt |
| C. | Weber/Ampere |
| D. | Weber/Ampere2 |
| Answer» D. Weber/Ampere2 | |
| 85. |
An RLC series circuit is underdamped. To make it overdamped, the value of R |
| A. | has to be increased |
| B. | has to be decreased |
| C. | has to be increased to infinity |
| D. | has to be reduced to zero |
| Answer» B. has to be decreased | |
| 86. |
In a parallel resonant circuit, the circuit current at resonance is maximum. |
| A. | True |
| B. | False |
| Answer» C. | |
| 87. |
Material which lack permanent magnetic dipoles are known as |
| A. | paramagnetic |
| B. | diamagnetic |
| C. | ferromagnetic |
| D. | ferrimagnetic |
| Answer» C. ferromagnetic | |
| 88. |
Assertion (A): Silicon is less sensitive to changes in temperature than germanium. Reason (R): Cut in voltage in silicon is less than that in germanium. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» D. A is false but R is true | |
| 89. |
The law J = σE, where J is current density, σ is electrical conductivity and E is field strength is |
| A. | Ohms law |
| B. | Gauss law |
| C. | Amperes law |
| D. | Biot-Savart law |
| Answer» B. Gauss law | |
| 90. |
If the diameter of a wire is doubled, its current carrying capacity becomes |
| A. | one-fourth |
| B. | half |
| C. | twice |
| D. | four times |
| Answer» E. | |
| 91. |
The number of valence electrons in pentavalent impurity is |
| A. | 5 |
| B. | 4 |
| C. | 3 |
| D. | 1 |
| Answer» B. 4 | |
| 92. |
Two materials having temperature coefficients of 0.004 and 0.0004 respectively are joined in series. The overall temperature coefficient is likely to be |
| A. | 0.08 |
| B. | 0.04 |
| C. | 0.001 |
| D. | 0.0001 |
| Answer» D. 0.0001 | |
| 93. |
Assertion (A): Electronic and Ionic polarization in a polyatomic gas are independent of temperature. Reason (R): The orientation polarization is independent of temperature. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» D. A is false but R is true | |
| 94. |
The minority carrier life time and diffusion constant in a semiconducting material are 100 μs and 100 cm2/s respectively. The diffusion length of carriers is |
| A. | 0.1 cm |
| B. | 0.01 cm |
| C. | 0.0141 cm |
| D. | 1 cm |
| Answer» B. 0.01 cm | |
| 95. |
The core of a coil has a length of 10 cm. The self inductance is 8 mH. If the core length is doubled, all other quantities remaining the same, the self inductance will be |
| A. | 32 mH |
| B. | 16 mH |
| C. | 8 mH |
| D. | 4 mH |
| Answer» E. | |
| 96. |
Assertion (A): Atomic number of sodium is 11. Reason (R): Sodium has a body centred cubic lattice. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» C. A is true but R is false | |
| 97. |
In paramagnetic materials |
| A. | permanent magnetic dipoles exist but the interaction between neighbouring dipoles is negligible |
| B. | permanent magnetic dipole do not exist |
| C. | permanent magnetic dipoles exist and the interaction between neighbouring dipoles is very strong |
| D. | permanent magnetic dipole moment may or may not exist |
| Answer» B. permanent magnetic dipole do not exist | |
| 98. |
Above ferroelectric curie temperature, spontaneous polarization in ferroelectric materials becomes stronger. |
| A. | True |
| B. | False |
| Answer» C. | |
| 99. |
Which capacitor-store higher amount of energy? |
| A. | Air capacitor |
| B. | Paper capacitor |
| C. | Mica capacitor |
| D. | Plastic film capacitor |
| Answer» D. Plastic film capacitor | |
| 100. |
Diamond is a paramagnetic material. |
| A. | True |
| B. | False |
| Answer» C. | |