ECAT Physics Online Test With Answers

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ECAT Physics Online Test

Sr. # Questions Answers Choice
1 Truth table of logic function: Summarizes its output values Tabulates all its input conditions only Display all its input/output possibilites Is not based on logic algebra None of these
2 To designate the voltage as low or 0 by a logic gate, the specified minimum value is: 0.2 volt 0.8 volt 0 volt 2.0 volt 5.0 volt
3 Op-amp has been discussed as comparator of: Distances Voltages Velocities Magnetic fields Both (A) and (C)
4 To turn the transistor OFF, the base current is set: At maximum value At zero Either (A) or (B) All are correct None of correct
5 In AND gate, the output is 1 if: Both inputs are 0 Both inputs are 1 Only one input is 0 Both (A) and (B) Both (A) and (C)
6 A digital system deals with quantities which has discrete values: Two in number One in number Three in number Four in number None of these
7 The number of input terminals of an op-amp is: One Two Three Four None of these
8 An electronic computer is basically a vast arrangement of electronic switches which are made from Resistors Transistors N -type crystals P-Type crystals Capacitors
9 To display a digit of EIGHT, the number of ON LED'S are: Two Three Five Seven Eight
10 To make an LED, it is impreacticable to use: Silicon Gallium arsenide Gallium arsenide phosphide Iron Both (B) and (C)
11 In the text book, the transistor amplifier circuit is a: Common emitter circuit Common collector circuit Common base circuit Any of these None of these
12 A transistor has: One region Two regions Three regions Four regions None is correct
13 The number of LED'S needed to display all the digits is: Four Five Nine Six Seven
14 A diode which can turn its current ON and OFF in nono seconds is called: LED Photodiode An ordinary diode. Both (A) and (B) Both (B) and (C)
15 In full wave rectification, simultaneous action is that: Two diodes conduct and two do not. One diode conduct and three do not. Three diodes conduct and one does not. All the four diodes conduct None of these
16 In reverse-biased p-n junction, the reverse current is due to flow of: Minority charge carriers Majority charge carriers Free electrons from p to n-region Holes from n to p-region all are true except (B)
17 In the forward biases situation, the current flowing across the p-n junction is a few: amperes Milli amperes Micro amperes Pico amperes None of these
18 A potential barrier of 0.7 V exists across p-n junction made from: Germanium Silicon Arsenic Gallium Indium
19 A hole in p-type my be due to: Trivalent impurity Breking of some covalent bond Pentavalent impurity Germanium Either (A) or (B)
20 Majority charge carriers in the p-region of p-n junction are: electrons positrons Holes Neutrons None of these
21 All the valence electrons present in a crystal of silicon are bound in their orbits by Ionic bond covalent bond Molecular bond Both (A) and (B) Both (B) and (C)
22 Crystal of germanium or silicon in its pure form at absolute zero acts as: A conductor A semiconductor an insulator Both (A) and (C) Both (A) and (B)
23 The use of chips in electrons is described in the form of: Yellow boxes Black boxes Red boxes White boxes Orange boxes
24 Silicon is one of the mot commonly used: onductor Dielectric Insulator Semiconduction Both (B) and (C)
25 Tick the one which is not polymer solid:
 Zirconia Polythene Nylon Synthetic rubber None of these
26 Polymers are the chemical combination of carbon with: Nitrogen Oxygen Hydrogen All of these None of these
27 Examples of crystalline solids are: Cooper NaCl Zirconia Both (A) and (B) All of these
28 Examples of polymeric substances are: Plastic Synthetic rubbers Zirconia All of these Both (A) and (B)
29 A structure of polymeric solid is: An ordered structure A disordered structure Intermediate between order and disorder Any of these None of these
30 When relatively simple molecules are chemically combined into massive molecules, the reaction is called: Fission reaction Fusion reaction Polymerization Any of these None of these
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