ECAT Pre General Science Physics Chapter 16 Alternating Current Online Test With Answers

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ECAT Pre General Science Physics Chapter 16 Alternating Current Online Test

Sr. # Questions Answers Choice
1 The bridge circuit of full wave rectification uses one diode two diode three diode four diode
2 In half wave rectification both halves of the input voltage is used only one half of the input voltage is used either of these none of these
3 During the negative half-cycle of the half-wave rectification, the diode does not conduct conducts either of these none of these
4 During the positive half-cycle in the half-wave rectification,the diode does not conduct conducts either of these neither of these
5 The output voltage of half wave rectification is in the form of a smooth curve a smooth wave pulses all of the above
6 Conversion of alternating current into direct current is called amplification rectification conduction polarization
7 A diode characteristic curve is a plot between current and time voltage and time voltage and current forward voltage and reversed voltage
8 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
9 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
10 When the pn-junction is forward biased. the current flows through it is of the order of mili-amperes amperes nano-amperes micro-amperes
11 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
12 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
13 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
14 Average value of A.C voltage during one cycle is 1 Zero Maximum Variable
15 A changing magnetic flux creates around itself An electromotive force An electric field (changing electric flux) Magnetic field None of the above
16 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
17 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>
18 Transmitting antenna emits Magnetic waves Electric waves Electromagnetic waves Sound waves
19 Electromagnetic waves transmit energy equal to 1/2 mv<sup>2</sup> m<sub>o</sub>c<sup>2</sup> hf/c hf
20 Which one of the following Electro-magnetic wave have the highest frequency and shortest wave-length X-rays Ultraviolet rays y-rays Cosmic rays
21 Chock consumes externally small Charge Current Power Potential
22 Which one of the following waves belongs to electromagnetic spectrum Radio and TV waves Radar waves Micro waves All of them
23 In frequency modulation (FM), the carrier waves amplitude Remains constant Increase Decreases None of these
24 If the value of C in a series RLC circuit is increased, the resonant frequency Is not affected Increase Remains the same Decreases
25 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
26 The total reactance of a series RLC circuit at resonance is zero Equal to the resistance Infinity Capacitive
27 SI unit of impedance is hertz henry ampere ohms
28 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>
29 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
30 At resonance frequency the impedance of parallel resonance circuit is Maximum Minimum Zero None of the above
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