PPSC Physics Chapter 6 Electricity and Magnetism With Answers

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PPSC Physics Chapter 6 Electricity and Magnetism

Sr. # Questions Answers Choice
1 If we use two diodes and a centre tapped transformer we will get. A transistor An amplifier A half wave rectifier A full wave rectifier
2 Photo diodes are used as Optical fibre receivers Automatic switching Logic circuits All of the above
3 The eight most common element in the universe by mass is Ge C Si As
4 Pure silicon has valence electrons 1 2 3 4
5 The typical value of forbidden energy gap in germinium is. 0.7 eV 1.0 eV 1.4 eV 10 eV
6 Which one is not a semiconductor. Go As Ge Sc In
7 The most common trivalent impurities are Boron , indium Arsenic, indium Arsenic, Antimony Aluminium, Boron
8 With increase in temperature the electrical conductivity of intrinsic conductors. Increases Descreases Remain unaffected First increases then decreases
9 In a half wave rectifier the rms value of the A.C. component of the wave is. Less than D.C. value Great her than D.C. value Equal to D.C. value Zero
10 Select the one that is not a donar P AS Sb In
11 Which one of the following materials has negative temperature coefficient. Conductors Semiconductors Insulators Covalent bonds
12 A single silicon photovoltaic cell produces a current of the order of. A few miliamperes 10<sup>2</sup> A 10<sup>3</sup> A 10<sup>4</sup> A
13 A single silicon photovoltaic cell produces a voltage of the order of. 0.3 V 0.6 V 0.9 V 1.2 V
14 The advantage of LEDs over filament lamp is their Small size Reliability High operating speed All of the above
15 When light emitting diode is forward biased, it emits light of the colour Red Yellow Green All of these
16 In rectifiers silicon junction diodes are preferred to germanium type because. They are cheaper They are durable Their much lower reverse current makes them more efficient Of their geometry
17 If the output voltage is not smooth but pulsating then it can be made smooth by using a circuit known as. Filter Gate shunt Fuse
18 The circuit of full wave rectification consists of Only one diode Two diodes Three diodes Four diodes
19 The process due to which current flows only during alternate half cycle is known as. Filtration saturation Half wave rectification Full wave rectification
20 The process of converting A.C and D.C. is known as Amplification <sub>Filtration</sub> Rectification Saturation
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