# A oscilloscope 4cmX4cm screen has its own sweep out, fed back to its input if x&y Sensitivities are same, ...

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A oscilloscope 4cmX4cm screen has its own sweep out, fed back to its input if x&y Sensitivities are same, the oscilloscope will display

A) triangular wave B) diagonal line C) sine wave D) Circle

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The Lissajous pattern observed on screen of CRO is a straight line inclined at 45° to x axis. If X–plate input is 2 sin ωt, the Y–plate input is (1) 2 sin ωt (2) 2 sin (ωt + 45°) (3) 2 sin (ωt – 45°) (4) 22 sin ωt + 45°)

The two inputs of a CRO are fed with two stationary periodic signals. In the X-Y mode, the screen shows a figure Which changes from ellipse to circle and back to ellipse with its major axis changing orientation slowly and repeatedly. The following inference can be made from this  A) The signals are not sinusoidal ... but not equal C) The signals are sinusoidal with their frequencies very close but not equal D) There is a constant but small phase difference between the signals

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

The p.u. parameter for a 500 MVA machine on its own base are: inertia, M = 20 p.u. ; reactance, X = 2 p.u. The p.u. values of inertia and reactance on 100 MVA common base, respectively, are (A) 4, 0.4 (B) 100, 10 (C) 4, 10 (D) 100, 0.4

When The dc converter in figure shown has a resistance load of R = 10 Ω and the input voltage is Vs 220 V the converter switch remains on, its voltage drop is Vo -2 V. The chopping frequency is fI K sW Vs If the duty cycle is 50%, determine: (a) the average output voltage V (b) the RMS output voltage Vo (c) the converter efficiency (d) the effective input resistance of the converter

The trace on an oscilloscope continually moves to the right of the screen when  (a) the sweep is triggered. (b) the sweep period is larger than the signal period. (c) the sweep period is smaller than the signal period. (d) there is no weep.

Two sinusoidal signals of the same frequency are displayed on a dual-trace oscilloscope. One complete cycle of each signal covers 6 cm of the horizontal scale and the starting point of the horizontal scale and the starting point of the two signals are separated by 0.5 cm. The phase difference between the two signals in degrees is  (a) 30 (b) 45 (c) 60 (d) 90

A binary ladder with R -2R network has R = 20K Ohms. The total resistance looking out toward the LSB input is (a) 20KOhms (b) 40KOhms (c) 10KOhms (d) 30KOhms

A radioactive isotope has a half-life of 10 days. If today there are 125 g of it left, what was its original weight 40 days earlier  (a) 600 g (b) 1000 g (c) 1250 g (d) 2000 g

If the back emf of a dc motor is doubled and its speed is also doubled, the torque developed in the machine will  (1) get doubled (2) become 4 times (3) get halved (4) remain unaltered

When an antenna of input resistance 73 ohm is connected to a 50-ohm line and if the losses are ignored then its efficiency will be nearly   (A) 0.19 (B) 0.81 (C) 0.97 (D) 1.19

DC ammeter has a resistance of 0.1 Ω and its current range is 0-100 A. If the range is to be extended to 0-300 A, what shunt resistance need to be connected?  A) 0.025 Ω B) 0.05 Ω C) 0.015 Ω D) 0.03 Ω

Two sinusoidal signals having the same amplitude and frequency are applied to the X and Y inputs of a CRO. The observed Lissajous figure is straight line. The phase shift between the two signals would be (1) Zero (2) 90 degrees (3) Either zero or 180 degrees (4) Either 90 degrees or 270 degrees

If the distance of screen from a CRT to center of deflection plates is 15 cm, the length of deflection plates is 2 cm, the distance between the plates is 1 cm and accelerating voltage is 500 V, deflection sensitivity is   (a) 33.2 V/cm (b) 0.03 cm/V (c) 66.4 V/cm (d) 0.015 cm/V

A circuit is said to be free from phase distortion if its phase response shows: (1) Quadrature variation with frequency (2) Independent of frequency (3) Linear variation with frequency (4) Proportional to frequency

Negative feedback amplifier has a signal corrupted by noise as its input. The amplifier will   (A) Amplify the noise as much as the signal (B) Reduce the noise (C) Increase the noise (D) Not effect the noise

An accelerometer has input range of 0 to 10g, natural frequency 30 Hz and mass 0.001 kg. The range of the secondary displacement transducer in mm required to cover the input range is (A) 0 to 2.76 (B) 0 to 9.81 (C) 0 to 11.20 (D) 0 to 52.10

For an 8 bit DAC, reference voltage is 10 V. If input to DAC starting from MSB is 10111100, output (in volts) is  A) 5.8 B) 6.4 C) 7.3 D) 8.2

Three lamps are connected in parallel across a 120 Volt source. If one lamp burns out, the remaining two will be: A. Glow dimmer B. Glow brighter C. Not light D. Glow with the same brightness as before

If it takes a transmitted signal 1m sec to go up to the target and come back after reflection, how far is the transmitter from the target? A) 150 Km B) 150 m C) 15 Km D) 1500 m

A 200 V dc motor takes a field current of 2 A to generate a back emf of 180 V. If the field winding resistance is 80 Ω, the resistance of the shunt field regulator is (A) 10 Ω (B) 20 Ω (C) 100 Ω (D) 180 Ω

In CRO, Lissajous pattern will be a straight line, if the two signals are of same frequency with a phase difference of (a) 0° (b) 180° (c) 360° (d) All of these

If the secondary turns of a transformer are doubled and at the same time primary voltage is reduced to half then the secondary voltage will

Three equal impedances are first connected in delta across a 3 -phase balanced supply. If the same impedances are connected in star across the same supply then,

A digital voltmeter has a read-out range from 0 to 9999 counts. When full scale reading is 9.999 V, the resolution of the instrument will be (a) 100 mV (b) 99 mV (c) 9 mV (d) 1 mV

A passive two port network is in a steady state. Compared to its input, the steady state output can never offer  A) Higher voltage B) Lower impedance C) Greater power D) Better regulation

A passive 2-port network is in a steady state, compared to its input, the steady state output can never offer   (a) Higher voltage (b) Lower impedance (c) Greater power (d) Better regulation

Three 60 W bulbs are in parallel across the 230 V power line. If one bulb burns out

A Lissajous pattern on an oscilloscope has 5 horizontal tangencies and 2 vertical tangencies. The frequency of the horizontal input is 1000 Hz. What is the frequency of the vertical input?  (A) 400 Hz (B) 5000 Hz (C) 4000 Hz (D) 2500 Hz

A high-pass filter has a resistance R = 2 kΩ The lowest input frequency to be passed is 7.5 kHz. The value of suitable coupling capacitor must be: A) 0.001 pico Farad B) 0.01 pico Farad C) 0.1 pico Farad D) 1 pico Farad

An ac voltmeter using full -wave rectification and having a sinusoidal input has an ac sensitivity equal to  (1) 1.414 times dc sensitivity (2) dc sensitivity (3) 0.9 times dc sensitivity (4) 0.707 times dc sensitivity

A high pass filter has a resistance R = 2 kΩ. The lowest input frequency to be passed is 7.5 KHz. The value of suitable coupling capacitor must be : (A) 0.1 pF (B) 1 pF (C) 0.1 μ F (D) 1 μ F

If the input to a differentiating circuit is a saw-tooth wave, then output will be …………….. wave: A) square B) rectangular wave C) triangular wave D) rectified sine wave

In a weighted-resistor digital-to-analog converter with 8-bit input, if the resistance corresponding to the MSB is 2K, what will be the resistance corresponding to the LSB?  (a) 250 Ω (d) 512 KΩ (c) 256 KΩ (d) 25.5 Ω

If a step function is applied to the input of a system and the output remains below a certain level for all the time, the system is?

The magnitude of the open-circuit and short circuit input impedance of a transmission line are 100 ohm and 25 ohm respectively. The characteristic impedance of line is:  (1) 25 ohm (2) 50 ohm (3) 75 ohm (4) 100 ohm

A coil has 100 turns produces a flux change of 0.01 webers when current changes by 100mA. Its inductance (in H) value is  A) 5 B) 10 C) 1 D) 0.1

If three amplifiers having the same bandwidth are cascaded, the bandwidth of the resulting amplifier will be (a) Better than that of each stage (b) Worse than that of each stage (c) Same as that of each stage (d) None of the above

A 3-phase induction motor is running at slip ‘s’. If its two supply leads are interchanged, then the operating slip at that instant will be:

If the load current and flux of a DC motor are held constant, and voltage applied across its armature is increased by 10%, its speed will:  (A) Decrease by 10%. (B) Remain unchanged. (C) Increase by 10%. (D) Increase by 20%.

An eight bit digital data 10101100 is fed to an ADC. The reference voltage is +10V. The analog output voltage will be:  (1) 1.05V (2) 6.74V (3) 10.10V (4) 5.15V

Lissajous pattern obtained on a CRO screen is a circle. Frequency of two signals are   (a) Equal (b) Unequal (c) Zero (d) Infinity

Which of the following amplifier configurations has the lowest input resistance?  A) Common Emitter B) Common Base C) Common Collector D) Emitter Follower