[{"id":253856,"question":"Photo cells are used for :","choices":[{"text":"Security and counting system","value":"A"},{"text":"Automatic door system","value":"B"},{"text":"Automatic street lighting","value":"C"},{"text":"All of these","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253855,"question":"In a photocell, certain metal emits electrons for :","choices":[{"text":"Visible light","value":"A"},{"text":"Infrared light","value":"B"},{"text":"Ultraviolet light","value":"C"},{"text":"All of these","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253854,"question":"In a photocell, cesium coated oxidized silver emits electrons for :","choices":[{"text":"Visible light","value":"A"},{"text":"Infrared light","value":"B"},{"text":"Ultraviolet light","value":"C"},{"text":"All of these","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253853,"question":"In a photocell, sodium and potassium emit electrons for:","choices":[{"text":"Visible light","value":"A"},{"text":"Infrared light","value":"B"},{"text":"Ultraviolet light","value":"C"},{"text":"All of these","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":253852,"question":"A photo cell is based on:","choices":[{"text":"Compton effect","value":"A"},{"text":"Pair production","value":"B"},{"text":" Photo cell","value":"C"},{"text":"All of these","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253851,"question":"The maximum kinetic energy of emitted photoelectrons depends upon:","choices":[{"text":"The intensity of incident light","value":"A"},{"text":"Frequency of the incident light","value":"B"},{"text":"Temperature of the surface","value":"C"},{"text":"All of above","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253850,"question":"The minimum energy required by an electron to eject from metal surface is known as:","choices":[{"text":"Photo energy","value":"A"},{"text":"Critical energy","value":"B"},{"text":"Threshold energy","value":"C"},{"text":"Work function","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253849,"question":"In photoelectric effect, electrons are emitted:","choices":[{"text":"Slowly","value":"A"},{"text":"Intermittently","value":"B"},{"text":"Both (a) &amp; (b)","value":"C"},{"text":"Instantly","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253848,"question":"In photoelectric effect, electrons are emitted with:","choices":[{"text":"Same energy","value":"A"},{"text":"Different energies","value":"B"},{"text":"Both (a) &amp; (b)","value":"C"},{"text":"Intermittent energies","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253847,"question":"The photoelectric effect was explained by:","choices":[{"text":"Einstein","value":"A"},{"text":"Davison","value":"B"},{"text":"Hertz","value":"C"},{"text":" Planck","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":253846,"question":"The stopping potential for a certain metal is 10 volt, the max. Energy of emitted electron is:","choices":[{"text":"10 J","value":"A"},{"text":"100 J","value":"B"},{"text":"1.6 × 10-18 J","value":"C"},{"text":"1.6 × 10-19 J","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253845,"question":"There is a certain frequency below which no electrons are emitted from the metal surface, this frequency is\r\nknown as:","choices":[{"text":"Critical frequency","value":"A"},{"text":"Threshold frequency","value":"B"},{"text":"Maximum frequency","value":"C"},{"text":"Minimum frequency","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253844,"question":"The maximum energy of the photoelectrons depends upon:","choices":[{"text":"Frequency of incident light","value":"A"},{"text":"Intensity of incident light","value":"B"},{"text":"Nature of metal","value":"C"},{"text":"Both (a) &amp; (c)","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253843,"question":"The maximum energy of the photoelectrons can be determined by making the:","choices":[{"text":"Anode positive","value":"A"},{"text":"Anode negative","value":"B"},{"text":"Cathode positive","value":"C"},{"text":"Both (b) &amp; (c)","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253842,"question":"Moving photons posses:","choices":[{"text":"Energy","value":"A"},{"text":"Momentum","value":"B"},{"text":"Wavelength","value":"C"},{"text":"All of these","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253841,"question":"A human eye can detect the electromagnetic radiations of the type:","choices":[{"text":"Infrared radiations","value":"A"},{"text":"For- infrared radiations","value":"B"},{"text":"X-rays radiations","value":"C"},{"text":"Red radiations","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253840,"question":"A human eye can detect the electromagnetic radiations of the type:","choices":[{"text":"Infrared radiations","value":"A"},{"text":"For- infrared radiations","value":"B"},{"text":"X-rays radiations","value":"C"},{"text":"Red radiations","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253839,"question":"The energy of photon of wavelength 620 nm is:","choices":[{"text":"0.5 eV","value":"A"},{"text":"1.0 eV","value":"B"},{"text":"1.5 eV","value":"C"},{"text":"2.0 eV","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":253838,"question":"The energy of photon of energy 1 eV is:","choices":[{"text":"1240 nm","value":"A"},{"text":"1040 nm","value":"B"},{"text":"1000 nm","value":"C"},{"text":"620 nm","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":253837,"question":"The energy of photon of wavelength 1240 nm is:","choices":[{"text":"0.5 eV","value":"A"},{"text":"1.0 eV","value":"B"},{"text":"1.5 eV","value":"C"},{"text":"2.0 eV","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253836,"question":"Joule-second is the unit of:","choices":[{"text":"Energy","value":"A"},{"text":"Heat","value":"B"},{"text":"Planck’s constant","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253835,"question":"The dimensions of Planck’s constant “h” are same as that of:","choices":[{"text":"Momentum","value":"A"},{"text":"Angular momentum","value":"B"},{"text":"Work","value":"C"},{"text":"Torque","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253834,"question":"In full wave rectification by bridge the number of diodes\r\nrequired are","choices":[{"text":"3","value":"A"},{"text":"4","value":"B"},{"text":"2","value":"C"},{"text":"5","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253833,"question":"The diodes works on","choices":[{"text":"A.C","value":"A"},{"text":"D.C","value":"B"},{"text":"both A and B","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253832,"question":"The unit of gain (G) for non-inverting amplifier is","choices":[{"text":"Ampere","value":"A"},{"text":"ohm","value":"B"},{"text":"Volt","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253831,"question":"The simplest type of rectification known as half wave rectification is obtained by","choices":[{"text":"Using a transistor","value":"A"},{"text":"Suppressing the harmonics in A.C. voltage","value":"B"},{"text":"Suppressing half wave of A.C. supply by using diode","value":"C"},{"text":"Using a Coolidge","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253830,"question":"Inverting amplifier circuits have","choices":[{"text":"A very high input impendance","value":"A"},{"text":"A very low input impendance","value":"B"},{"text":"A low output impendance","value":"C"},{"text":"Both A and C","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253829,"question":"In full wave rectification, the output D.C. voltage across \r\nthe load is obtainedfor","choices":[{"text":"The positive half cycle of input A.C. (C) The complete cycle of \r\ninput A.C.","value":"A"},{"text":"The negative half cycle of input A.C.","value":"B"},{"text":"The complete cycle of","value":"C"},{"text":"All of the above","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253828,"question":"The method by which only one half of A.C cycle is converted into direct current\r\nis called","choices":[{"text":"half wave amplification","value":"A"},{"text":"half wave rectification","value":"B"},{"text":"Full wave rectification","value":"C"},{"text":"full wave amplification","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253827,"question":"In a full wave rectifier, the diode conducts during","choices":[{"text":"Both halves of the input cycle","value":"A"},{"text":"A portion of the positive half cycle of the input","value":"B"},{"text":"Positive half cycle of the input","value":"C"},{"text":"Positive half cycle of the input","value":"D"},{"text":"Both halves of the input cycle","value":"E"}],"correctAnswer":1},{"id":253826,"question":"A diode characteristics curve is a graph\r\nplotted between;","choices":[{"text":"Current and time","value":"A"},{"text":"Voltage and time","value":"B"},{"text":"Voltage and current","value":"C"},{"text":"Forward voltage and reverse current","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253825,"question":"Gain of operational amplifier is independent of;","choices":[{"text":"Internal structure","value":"A"},{"text":"External Structure","value":"B"},{"text":"Batteries","value":"C"},{"text":"Potential changes","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":253824,"question":"The junction potential for Germanium is;","choices":[{"text":"3v","value":"A"},{"text":"0.3 v","value":"B"},{"text":"7v","value":"C"},{"text":"0.7 v","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253823,"question":"A PN junction diode cannot be use:","choices":[{"text":"As rectifier","value":"A"},{"text":"For converting light energy to electrical energy","value":"B"},{"text":"For getting light radiation","value":"C"},{"text":"For increasing the amplitude of an ac signal","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253822,"question":"In a half wave rectifier circuit operating from 50 Hz mains frequency, the fundamental\r\nfrequency in the ripple would be:","choices":[{"text":"25 Hz","value":"A"},{"text":"70.7 Hz","value":"B"},{"text":"50 Hz","value":"C"},{"text":"100 Hz","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253821,"question":"A diode as a rectifier converts:\r\n","choices":[{"text":"A)c into D)c\r\n","value":"A"},{"text":"D)c into A)c","value":"B"},{"text":"Varying D)c current into constant D)c current\r\n","value":"C"},{"text":"High voltage into low voltage and vice-versa\r\n","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":253820,"question":"For full wave rectification, the minimum number of diodes used is:","choices":[{"text":"1","value":"A"},{"text":"2","value":"B"},{"text":"3","value":"C"},{"text":"4","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253819,"question":"A pure semiconductor has:","choices":[{"text":"An infinite resistance at 0<sup>o</sup>C)","value":"A"},{"text":"A finite resistance which does not depend upon temperature","value":"B"},{"text":"A finite resistance which decreases with temperature","value":"C"},{"text":"A finite resistance which increase with temperature","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253818,"question":"When two semiconductors of p- and n-type are brought into contact, they from a p-n\r\njunction which act like a:","choices":[{"text":"Conductor","value":"A"},{"text":"Amplifier","value":"B"},{"text":"Oscillator","value":"C"},{"text":"Rectifier","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253817,"question":"The diode charactristics curve is plot between","choices":[{"text":"I &amp; t","value":"A"},{"text":"V&amp; t","value":"B"},{"text":"V&amp; I","value":"C"},{"text":"None","value":"D"},{"value":"E"}],"correctAnswer":3}]