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The gain of a parabolic dish antenna of 1 m diameter -and 80% efficiency at 9.5 GHz is: a. 39 dB b. 78 dB c. 40 dB d. 45 dB

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A commutator with a diameter of 50 cm rotates at 1000 r.p.m. If brush width is 1.5 cm, the time of commutation will be (a) 0.168 m sec (b) 0.374 m sec (c) 0.481 m sec (d) 0.573 m sec

asked May 25, 2018 in Electrical Machine by Shimroz123
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asked Apr 12, 2018 in Electronics Engineering by Shimroz123
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asked May 17, 2018 in Electronics communication by Shimroz123
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asked May 23, 2018 in Electrical Engineering by Shimroz123
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asked Apr 9, 2018 in Electronics Engineering by Shimroz123
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asked May 24, 2018 in Electrical Measurements and Instrumentation by Shimroz123
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asked Apr 26, 2018 in Electronics Engineering by Shimroz123
1 answer 16 views

A two conductor 1 - pi line operates at 50 Hz.The diameter of each conductor is 20 mm and the spacing between the conductors is 3m, The height of conductor above the ground is 6 m. The capacitance of the line to neutral will be?

asked Mar 27, 2018 in Power system by Shimroz123
1 answer 12 views

A two conductor 1 - pi line operates at 50 Hz.The diameter of each conductor is 4 cm and are spaced 6 m apart. What is the capacitive susceptance to neutral per km?

asked Mar 27, 2018 in Power system by Shimroz123
1 answer 11 views

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asked Mar 27, 2018 in Power system by Shimroz123
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asked Apr 10, 2018 in Computer Engineering by Shimroz123
0 answers 15 views

A dc shunt motor runs at 500 r.p.m at 220 V. A resistance of 4.5 Ω is added in series with the armature for speed control. The armature resistance is 0.5 ohms. The current to stall the motor will be (1) 44 A (2) 50 A (3) 44.4 A (4) 60 A  

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
2 answers 95 views

The sending end and receiving end voltages of a three-phase transmission line are 10 kV/ph and 9.5 kV/ph, respectively. If the resistance drop is 150 V/ph and receiving end power factor is 0.8, the sending end power factor is (A) 0.745 lagging (B) 0.775 lagging (C) 0.8 lagging (D) 0.85 lagging

asked Apr 28, 2018 in Power system by Shimroz123
0 answers 21 views

A synchronous motor is delivering 80% of its rated output and is operating at UPF. If its excitation is increased, then  (1) the output delivered gets increased (2) its pf becomes lagging (3) the output delivered gets decreased (4) its pf becomes leading

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
1 answer 12 views

Earth coverage dish antenna is used in satellite system. It is characterized by the fact that  (a) It is a narrow beam antenna (b) It is Parabolic antenna (c) it is sharply focused within a small area of the surface of the earth (d) it is a wide angle antenna which covers a large area of the surface of the earth

asked May 15, 2018 in Electronics communication by Shimroz123
0 answers 21 views

The RF amplifier A is having 3 dB NF & 5 dB of gain, amplifier B is having 3.5 dB NF & 15 dB . For overall noise figure of the cascaded system, the correct statement is :  a. A as first stage & B as second stage offers minimum over all NF b. B as first stage & A as second stage minimum over all NF c. Both the combination will offer same overall NF d. Over all NF will be less than 3 dB.

asked Apr 12, 2018 in Electronics Engineering by Shimroz123
1 answer 17 views

A two conductor 1 - pi line operates at 50 Hz. The diameter of each conductor is 20 mm and the spacing between conductors is 3m. What is the inductance of each conductor per km?

asked Mar 27, 2018 in Power system by Shimroz123
1 answer 22 views

The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be  (A) 48.0% (B) 57.1% (C) 59.2% (D) 88.8%

asked May 17, 2018 in Electrical Machine by Shimroz123
1 answer 23 views

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asked Apr 14, 2018 in Instrumentation and control by Shimroz123
1 answer 13 views

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asked May 29, 2018 in Electronics Engineering by Shimroz123
0 answers 20 views

What is the energy stored in the magnetic field at a solenoid of 40 cm long and 4 cm diameter wound with 100 turns of wire carrying a current at 20A?  (A) 0.705 Joule (B) 0.789 Joule (C) 0.587 Joule (D) 0.658 Joule 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
1 answer 21 views

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asked Mar 27, 2018 in Power system by Shimroz123
1 answer 58 views

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asked Apr 29, 2018 in Electrical Engineering by Shimroz123
1 answer 46 views

In a differential amplifier the differential voltage gain is 500 and the common mode voltage gain is 0.5. The CMRR in dB is (a) 80 (b) 60 (c) 30 (d) 20

asked Apr 14, 2018 in Electrical Engineering by Shimroz123
1 answer 47 views

 A pulse radar has a pulse repetition frequency (PRF) of 3 KHz. If the radar is emitting at 10 GHz, what is the maximum unambiguous range for this radar? A) 5 Km B) 5 m C) 50 Km D) 15 m 

asked Jun 18, 2018 in Electrical Engineering by Shimroz123
1 answer 23 views

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asked May 8, 2018 in Electric Power Transmission by Shimroz123
1 answer 82 views

A drawn wire of resistance 5 Ω is further drawn so that its diameter becomes one-fifth of the original. What is its resistance with volume remaining the same ? (a) 25 Ω (b) 125 Ω (c) 625 Ω (d) 3125 Ω

asked Apr 25, 2018 in Electrical Engineering by Shimroz123
1 answer 13 views

If three wires of 3 ohms, 9 ohms and 5 ohms respectively are connected in series, what their resultant resistance? A.10 ohms B.12 ohms C.17 ohms D.5 ohms

asked May 15, 2018 in Basic concepts by Shimroz123
0 answers 43 views

The connected load of a consumer is 2 kW and his maximum demand is 1.5 kW. The load factor of the consumer is (a) 0.375 (b) 0.75 (c) 1.33 (d) None of these  

asked May 26, 2018 in Electric Power Transmission by Shimroz123
1 answer 15 views

System 1 : The first column of the RH array consists of the terms 6,3,9,-2, and 4. System 2 : The first column of the RH array consists of the terms 3,6,9,2, and -4. The number of unstable poles for system1, and system 2, are respectively, (A) 1,1 (B) none, none (C) 2,2 (D) 2,1

asked Apr 28, 2018 in Control System by Shimroz123
1 answer 28 views

 A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -  a) 16/9 b) 4 / 3 c) 3/4 d) 9 /16

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
1 answer 53 views

A 6-pole, 50Hz, 3-φ induction motor is running at 950 r.p.m. and has Cu loss of 5kW. The rotor input is (a) 10 kW (b) 95 kW (c) 100 kW (d) 9.5 kW 

asked May 25, 2018 in Induction Machine by Shimroz123
1 answer 40 views

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asked Mar 22, 2018 in Engineering Mechanics by Shimroz123
1 answer 58 views

A differential amplifier has a differential gain of 28000 and CMRR is 60 dB. What will be the value of common mode gain? A) Ac = 0.125 B) Ac = 0.33 C) Ac = 3 D) Ac = 28 

asked Jun 18, 2018 in Electronics Engineering by Shimroz123
1 answer 14 views

A d.c. source has an open circuit voltage of 30 V and an internal resistance of 1.5 Ohm. A resistive load is connected to the source. Maximum power dissipated in the load is (A) 300 W (B) 150 W (C) 45 W (D) 20 W

asked Apr 25, 2018 in Electrical Engineering by Shimroz123
1 answer 34 views

If the feedback factor of an amplifier is 0.1 and its gain without feedback is 40, then its gain with feedback is (a) – 13.3 (b) 200 (c) 8 (d) 10 

asked May 25, 2018 in Amplifier by Shimroz123
0 answers 19 views

A material has conductivity of 10–2 mho/m and relative permittivity of 4. The frequency at which the conduction current in the medium is equal to the displacement current, is (a) 450 MHz (b) 900 MHz (c) 45 MHz (d) 90 MHz

asked May 25, 2018 in Physics by Shimroz123
0 answers 54 views

A 1-phase, 7.46 kW motor is supplied from a 400 V, 50 Hz A.C mains. Its efficiency is 85% and power factor is 0.8 lagging. Calculate the KVA input (1) 9.56 kVA (2) 5.4 Kva (3) 10.97 kVA (4) 8.6 kVA 

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
0 answers 37 views

An amplifier which has almost same gain and input resistance of a CE amplifier but of higher bandwidth is  A) Cascode amplifier B) Cascade amplifier C) Darligton amplfier D) CC amplifier

asked Apr 9, 2018 in Electronics Engineering by Shimroz123
1 answer 29 views

In a microwave test bench, why is the microwave signal amplitude modulated at 1 kHz?  (1) To increase the sensitivity of measurement (2) To transmit the signal to a far-off place (3) To study amplitude modulation (4) Because crystal detector fails at microwave frequencies

asked May 29, 2018 in Electronics Engineering by Shimroz123
1 answer 16 views

The line of sight communication requires transmit and receive antenna to face each other. If the transmit antenna is vertically polarized, for the best reception the receive antenna should be:  (1) Horizontally polarized (2) Vertically polarized (3) At 45° with respect to the horizontal polarization (4) At 45° with respect to the vertical polarization

asked Apr 9, 2018 in Electronics Engineering by Shimroz123
1 answer 13 views

Consider the following statements with regard to a GTO : 1. The turn-off gain of the GTO is large. 2. Large negative gate current pulses are required to turn off the GTO. 3. GTO has large reverse blocking capability. Which of the above statements is/are correct ? (a) 1 only (b) 2 only (c) 3 only (d) 1, 2 and 3

asked Apr 25, 2018 in Electrical Engineering by Shimroz123
1 answer 17 views

A simple phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor is  (A) 86.7% (B) 88.26% (C) 88.9% (D) 87.8%

asked May 17, 2018 in Transformer by Shimroz123
0 answers 16 views

A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the secondary. Assuming 100% efficiency, the primary current will be:  (A) 0.2 Amp. (B) 5 Amps. (C)10 Amps. (D) 20 Amps

asked Apr 9, 2018 in Electrical Engineering by Shimroz123
0 answers 10 views

How does the resistance of a circular conductor behave, if the diameter of the conductor is halved?  A) Remains unchanged B) Doubles C) Becomes 4 times D) Becomes one -fourth

asked Apr 9, 2018 in Electronics Engineering by Shimroz123
1 answer 33 views

An SSB transmitter produces a peak-to-peak voltage of 200 V across a 100 Ω antenna load. What is the Peak Envelope Power? A) 49.98 W B) 79.98 W C) 99.96 W D) 199.93 W

asked Jun 18, 2018 in Electronics Engineering by Shimroz123
0 answers 33 views

A carrier signal of 600 V rms with 75% amplitude modulation is applied to 75 ohm antenna. The total side band power (in watts) is  A) 4800 B) 450 C) 950 D) 1350 

asked Apr 9, 2018 in Electronics Engineering by Shimroz123

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