## general science

### Physics MCQ Questions and Answers Page - 9

1.
 Electric current in a metal wire is due to the flow of – A Electrons B Protons C Ions D Holes Answer : A Explanation :
2.
 Which of the following events occurred first  ? A Albert Einstein propounded the General Theory of Relativity B Max Planck unveiled the Quantum Theory C Marconi first transmitted a wireless signal D Madame Marie Curie became the first woman Nobel Prize winner Answer : B Explanation :
3.
 Tape recorder should  NOT  be kept near one of the following things  : A Clock B Magnet C Electrical switchboard D Radio Answer : B Explanation :
4.
 Which of the following is a good conductor of heat but a bad conductor of electricity  ? A Celluloid B Rubber C Asbestos D Mica Answer : D Explanation :
5.
 A photostat machine works on A Electromagnetic image making B Electrostatic image making C Magnetic image making D Thermal image making Answer : B Explanation :
6.
 Lightning is caused due to A Electric power B Electric discharge C Electric leak D Electric pressure Answer : B Explanation :
7.
 The device which transfer the signal from low resistance region to high resistance region is A Diode B Transistor C Capacitor D Inductor Answer : B Explanation :
8.
 A bird sitting on a high tension electric wire does not get electrocuted because A It has high resistance B The body is earthed C It does not form a closed path for the flow of current D Its feet are good insulators Answer : C Explanation :
9.
 Which of the following is arranged in order of decreasing conductivity  ? A Copper, Aluminium, Steel, Silver B Aluminium, Silver, Copper, Steel, C Copper, Silver, Aluminium, Steel, D Silver, Copper, Aluminium, Steel, Answer : D Explanation :
10.
 If a copper wire is increased to double its length, its resistance will become A Four times B One-fourth C Double D Half Answer : C Explanation :
11.
 The resistance of the human body (dry condition) is of the order of A $10^{1}&space;ohm$ B $10^{2}&space;ohm$ C $10^{3}&space;ohm$ D $10^{4}&space;ohm$ Answer : D Explanation :
12.
 A device which is used to limit the current in an electrical circuit is called a A Grid B Fuse C Hub D Conductor Answer : B Explanation :
13.
 The earth wire of a cable is connected to A The outer metallic body of the appliance B The fuse of the appliance C The filament of the appliance D Short circuitry of the appliance Answer : B Explanation :
14.
 Negative feedback in amplifiers A Increases bandwidth and decreases noise B Decreases bandwidth and decreases noise C Increases bandwidth and increases noise D Decreases bandwidth and increases noise Answer : A Explanation :
15.
 The metal whose electrical conductivity is more, is A Copper B Aluminium C Silver D Lead Answer : C Explanation :
16.
 Conversion of heat into electrical energy is achieved by using  : A Ammeter B Hydrometer C Voltmeter D Thermocouple Answer : D Explanation :
17.
 Moving electric charge produces  : A Magnetic field B Sound waves C Light rays D Heat waves Answer : A Explanation :
18.
 The  S.I.  unit of electric charge is  : A Ampere B Coulomb C E.S.U. D Kelvin Answer : B Explanation :
19.
 The best material for the core of a transformer is A Stainless steel B Mild steel C Hard steel D Soft iron Answer : D Explanation :
20.
 In AC circuits, AC meters measure A Mean values B Rms values C Peak values D Mean square values Answer : B Explanation :
21.
 The width of depletion layer of a P-N junction A Decreases with light doping B Increases with heavy doping C Is independent of applied voltage D Is increased under reverse bias Answer : D Explanation :
22.
 Safety fuse wire used in domestic electrical appliances is made of metal of low A Resistance B Melting point C Specific gravity D Conductance Answer : B Explanation :
23.
 Which of the following is a conductor of electricity  ? A Rubber B Pure water C Salt water D Benzene Answer : C Explanation :
24.
 A fuse wire is made of  : A An alloy of tin and copper B An alloy of tin and lead C An alloy of tin and aluminium D An alloy of nickel and chromium Answer : B Explanation :
25.
 For which of the following substances, the resistance decreases with increase in temperature  ? A Pure silicon B Copper C Nichrome D Platinum Answer : A Explanation :
26.
 Full form of  CFL  used in place of electric bulbs is A Compact fluorescent lamp B Constantan filament lamp C Closed filament lamp D Closed fluorescent lamp Answer : A Explanation :
27.
 Indicate the false statement about the resistance of a wire. A It depends on material of wire B It is directly proportional to the length of wire C It is directly proportional to the area of cross-section of wire D Resistance of metallic wire increases with increase in temperature Answer : C Explanation :
28.
 A wire carrying current is A Positively charged B Negatively charged C Neutral D Charged with a type depending upon current strength Answer : C Explanation :
29.
 The method of magnetisation is  : A Hammering a magnet B Heating a magnet C Passing direct current through it D Passing alternating current through it Answer : C Explanation :
30.
 Magnetic keepers are pieces of A Nickel B Cobalt C Steel D Soft iron Answer : D Explanation :
31.
 Certain substances loose their electrical resistance completely at super low temperature. Such substances are called. A Super conductors B Semi-conductors C Dielectrics D Perfect conductors Answer : A Explanation :
32.
 ‘Farad’  is the unit of  : A Capacitance B Inductance C Resistance D Conductance Answer : A Explanation :
33.
 Solids which conduct electricity at higher temperature but not at lower temperature are called A Super-conductor B Metallic-conductor C Semi-conductor D Insulator Answer : C Explanation :
34.
 Light scattering takes place in A Colloidal solutions B Acidic solutions C Electrolyte solutions D Basic solutions Answer : A Explanation :
35.
 A good conductor while carrying current is A Alternately charged positive and negative B Negatively charged C Positively charged D Electrically neutral Answer : B Explanation :
36.
 In a filament type light bulb most of the electric power consumed appears as A Visible light B Infra-red rays C Ultra-violet rays D Fluorescent light Answer : B Explanation :
37.
 When two semiconductors of p and n-type are brought in contact, they form p-n junction which acts like a/an A Conductor B Oscillator C Rectifier D Amplifier Answer : C Explanation :
38.
 Ohm’s law is valid in case of A Semi-conductor B Conductor C Super  Conductor D Insulator Answer : B Explanation :
39.
 The Laser is a beam of radiations which are A Non-coherent and monochromatic B Coherent and monochromatic C Non-coherent and non-monochromatic D Coherent and non-monochromatic Answer : B Explanation :
40.
 Magnetic keepers are used to protect magnets from  : A Earth’s magnetic field B Effect of other magnets C Self-demagnetization D Demagnetization due to heating Answer : C Explanation :
41.
 A current carrying conductor is associated with A A magnetic field B An electric field C An electro- magnetic field D An electrostatic field Answer : C Explanation :
42.
 Tesla is a unit of magnetic : A Flux B Induction C Moment D Field Answer : D Explanation :
43.
 Super conductors are substances that A Offer minimum resistance to flow of electric current B Conduct electricity at low temperature C Conduct electricity at high temperature D Offer high resistance to the flow of electric current Answer : A Explanation :
44.
 In a conductor A There is no conduction band B The forbidden energy gap is very wide C The forbidden energy gap is very narrow D The valence band and the conduction band overlap each other Answer : D Explanation :
45.
 In which one of the following the phenomenon of total internal reflection of light is used  ? A Formation of mirage B Working of binoculars C Formation of rainbow D Twinkling of stars Answer : C Explanation :
46.
 A wire of resistance  R  is cut into  ‘n’  equal parts. These parts are then connected in parallel. The equivalent resistance of the combination will be A $nR$ B $\frac{R}{n}$ C $\frac{n}{R}$ D $\frac{R}{n^{2}}$ Answer : D Explanation :
47.
 Which of these waves can be polarized  ? A Sound waves in air B Longitudinal waves on a string C Transverse waves on a string D Light waves Answer : D Explanation :
48.
 If a wire of resistance  R  is melted and recasted to half of its length, then the new resistance of the wire will be A $\frac{R}{4}$ B $\frac{R}{2}$ C $R$ D $2R$ Answer : A Explanation :
49.
 The purpose of choke in a fluorescent lamp is  : A To increase the current flow B To decrease the current flow C To decrease the resistance D To decrease the voltage momentarily Answer : B Explanation :
50.
 When number of turns in a coil is tripled, without any change in the length of coil, its self-inductance becomes  ? A Nine times B Three  times C Six  times D One-third Answer : A Explanation :
51.
 Unit of resistance is  : A $volt^{2}&space; B $\frac{volt}{ampere}$ C $\frac{ampere}{volt}$ D $volt&space;\times&a Answer : B Explanation :
52.
 S.I.  unit of Magnetic flux is A Weber B Weber/m C Weber/m4 D Weber-m2 Answer : A Explanation :
53.
 To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor A Should be made of a good conductor but can be of any shape B Should be in the form of vertical rod C Can be of any shape D Should be made of a good conductor like copper with sharp-pointed edges Answer : D Explanation :
54.
 The magnitude of current flowing between two end points of a conductor is proportional to the potential difference between them and is called as  : A Avogadro’s law B Rault’s law C Ohms law D Faraday’s law Answer : C Explanation :
55.
 Which of the following was the first theory of super conductivity  ? A Ginzburg Landau theory B London theory C Resonating valence bond theory D Quantum field theory Answer : B Explanation :
56.
 Which of the following is an insulator  ? A Mercury B Carbon C Germanium D Glass Answer : D Explanation :
57.
 Name the process by which bubbles from liquid are formed  ? A Effervescence B Surface Tension C Surface Energy D Degasification Answer : A Explanation :
58.
 What is the name of the device used to convert alternating current into direct current  ? A Ammeter B Galvanometer C Rectifier D Transformer Answer : C Explanation :
59.
 The  ‘Choke’  used with a tube light is basically A An inductor B A capacitor C A transformer D A resistor Answer : A Explanation :
60.
 Which one among the following components is used as an amplifying device  ? A Transformer B Diode C Capacitor D Transistor Answer : D Explanation :
61.
 A galvanometer can be converted into a voltmeter by connecting with it a A High resistance in parallel B Low resistance in parallel C High resistance on series D Low resistance in series Answer : C Explanation :
62.
 At low temperature, Lead behaves as a  : A Semi-conductor B Super conductor C Insulator D Conductor Answer : B Explanation :
63.
 If electric resistance is to be decreased, then the number of resistances should be connected in  _______________ A Series B Parallel C Mixed arrangement D None of these Answer : B Explanation :
64.
 The material used in electric heater is A Tungsten B Nichrome C Brass D Steel Answer : B Explanation :
65.
 Which one of the following is an ohmic conductor  ? A Germanium B Silicon C Carbon D Silver Answer : D Explanation :
66.
 The frequency of direct current is  ______________ A Zero B 50 Hz C 60 Hz D 100 Hz Answer : A Explanation :
67.
 For photoelectric effect to take place, the metal used as the cathode should have  ______________ A High melting point B Low melting point C Low work function D Low resistance Answer : C Explanation :
68.
 Flemings  “Left hand Rule”  is associated with the effect of A Electric field on current B Magnetic field on magnet C Electric field on magnet D Magnetic field on current Answer : D Explanation :
69.
 Where is a transistor most likely to be found  ? A Wrist watch B Fuse C Hearing aid D Fluorescent lamp Answer : C Explanation :
70.
 Which one of the following is a good electrical conductor  ? A Graphite B Diamond C Peat D Charcoal Answer : A Explanation :
71.
 Which one among the following components can not be developed within  an  “integrated circuit”   ? A Diode B Triode C Transformer D Transistor Answer : C Explanation :
72.
 Electromagnet is constructed with which of the following  ? A Steel B Soft Iron C Aluminium D Nickel Answer : B Explanation :
73.
 The fuse in an electric circuit is connected in A Series with neutral B Parallel to live C Parallel to neutral D Series with live Answer : D Explanation :
74.
 ___________   through a plane surface is the product of the magnetic flux density normal to the surface and the area of the surface. A Magnetic susceptibility B Magnetic resonance C Magnetic flux D Magnetic pulse Answer : C Explanation :
75.
 ____________   states that the total current entering a junction is equal to the current leaving the junction. A Lenz’s Law B Hooke’s Law C Ohm’s Law D Kirchhoff’s First Law Answer : D Explanation :
76.
 Which material is used in the manufacturing of electric heater coil  ? A Copper B Iron C Nickel D Nichrome Answer : D Explanation :
77.
 The coil wire in the electric room heater or electric cooking heater is called  _____________ . A Circuit B Element C Filament D Cells Answer : B Explanation :
78.
 A common fluorescent tube contains  _____________ . A Argon vapour B Mercury vapour C Sodium vapour D Neon vapour Answer : B Explanation :
79.
 Kilowatt hour (kWh) represents the unit of which of the following  ? A Electrical Power B Force C Momentum D Energy Answer : D Explanation :
80.
 Rectifiers are used to convert A High voltage to low voltage B Low voltage to High voltage C DC  to  AC D AC  to  DC Answer : D Explanation :
81.
 The metal cap of an electric cell is generally the  _____________  terminal of the electric cell. A Negative B Positive C Neutral D Devoid Answer : B Explanation :
82.
 When two or more cells are connected to each other by opposite terminals, then it is called as  _____________ . A Electric bulb B Switch C Battery D Electric current Answer : C Explanation :
83.
 A positively charged particle projected towards west is deflected towards north by a magnetic field. What is the direction of magnetic field  ? A Toward south B Toward east C Downward D Upward Answer : D Explanation :
84.
 Which of the following affects the resistance of the wire  ? A Resistivity B Length of wire C Area of cross section of wire D All options are correct Answer : D Explanation :