ECAT Pre General Science Online Test With Answers

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ECAT Pre General Science Online Test

Sr. # Questions Answers Choice
1 A diode characteristic curve is a plot between current and time voltage and time voltage and current forward voltage and reversed voltage
2 When the pn-junction is connected reversed biased, its resistance is of the order of few ohms few kilo-ohms few mega-ohms few mili-ohms
3 When the pn-junction is in reversed biased, current flows through the junction due to the majority carriers minority carriers either of them none of them
4 When the pn-junction is forward biased. the current flows through it is of the order of mili-amperes amperes nano-amperes micro-amperes
5 When the p-n junction is forward biased its resistance is of the order of few mega ohms few kilo ohms few ohms few milli ohms
6 The value of the potential difference across the depletion region for the case of germanium is 0.3 V 0.5 V 0.7 V 0.9 V
7 A p-n junction is formed when a crystal of silicon is growth in such a way that its one half is doped with trivalent impurity and the other half with a impurity from 2nd group fourth group fifth group sixth group
8 Average value of A.C voltage during one cycle is 1 Zero Maximum Variable
9 A changing magnetic flux creates around itself An electromotive force An electric field (changing electric flux) Magnetic field None of the above
10 When electrons in the transmitting antenna vibrate 94000 time per second, they produce radiowaves having frequency 9.4 kHz 940 kHz 94 kHz None of these
11 In free space, the speed of electromagnetic waves is 3 x 10<sup>8</sup>ms<sup>-1</sup> 3 x 10<sup>6</sup>ms<sup>-1</sup> 4 x 10<sup>7</sup>ms<sup>-1</sup> 3 x 10<sup>9</sup>ms<sup>-1</sup>
12 Transmitting antenna emits Magnetic waves Electric waves Electromagnetic waves Sound waves
13 Electromagnetic waves transmit energy equal to 1/2 mv<sup>2</sup> m<sub>o</sub>c<sup>2</sup> hf/c hf
14 Which one of the following Electro-magnetic wave have the highest frequency and shortest wave-length X-rays Ultraviolet rays y-rays Cosmic rays
15 Chock consumes externally small Charge Current Power Potential
16 Which one of the following waves belongs to electromagnetic spectrum Radio and TV waves Radar waves Micro waves All of them
17 In frequency modulation (FM), the carrier waves amplitude Remains constant Increase Decreases None of these
18 If the value of C in a series RLC circuit is increased, the resonant frequency Is not affected Increase Remains the same Decreases
19 The phase angle of a series RLC circuit at resonance is 180<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span> 90<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span> 0<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span> None of the these
20 The total reactance of a series RLC circuit at resonance is zero Equal to the resistance Infinity Capacitive
21 SI unit of impedance is hertz henry ampere ohms
22 In series RC circuit when R=Xc, then the phase angle is 0<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span> 90<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span> 70<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span> 45<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
23 An A.C. voltage is applied across the inductor. When the frequency of the voltage is increased, the current Decreases Increases Does not change Momentarily goes to zero
24 At resonance frequency the impedance of parallel resonance circuit is Maximum Minimum Zero None of the above
25 The impedance of RLC series resonance circuit at resonant frequency is Greater than R Equal to R Less than R None of these
26 An A.C. voltmeter read 250 volts. The frequency of alternating is 50 Hz, the peak value of voltage is 3525.0 volts 35.35 volts 353.5 volts 3.535 volts
27 To design a resonant circuit of frequency 100 KHz with an inductor of inductance 5 mH, we need a capacitor of capacitance 5.07 pF 50 pF 0.507 pF 507 pF
28 At resonance, the impedance of RLC series circuit is Maximum Zero Minimum Determinate
29 When either L or C is increased, the resonant frequency of the RLC series circuit Increases Decreases Remains the same Becomes zero
30 At resonance, the phase angle for RLC series resonance circuit equals 0<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span> 90<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span> 180<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span> 270<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
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