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| Physics 12th Chapter 18 - Electronics |
Physics 12th Chapter 18 - Electronics Solved MCQs, Important Short Questions and Long Questions Bank
MCQs
Please select the right answer.
1. A combination of p-type and N-type substance give rise to:
2. A diode, which can turn current ON and OFF in nanosecond is called:
3. A junction between p and n materials forms:
4. A light emitting diode (LED) emits light only when:
5. A light emitting diode is made from
6. A light emitting diode is made from:
7. A Light emitting diodes (LED) are made from semi-conductors:
8. A NAND gate with two inputs A &B has an out put 0, if
9. A photo diode can be used:
10. A photo diode is a semi conductor diode usually made from
11. A photo diode is used for
12. A photodiode can turn its current ON and OFF in:
13. A pn junction cannot be used as:
14. A potential barrier of 0.7 volt exist across p-n junction made from:
15. A Potential difference is developed across the depletion region of p-n junction due to:
16. A region having zero charge particle:
17. A single photo voltaic cell produces a current of:
18. A single photovoltaic cell produces a current of:
19. A transistor consists of three electrical contact which one of these is rectifying:
20. A transistor has:
21. A.C is converted into D.C by
22. All the valence electrons present in a crystal of silicon are bounded in their orbits by:
23. An n-type substance is:
24. An operational amplifier can be used as:
25. An operational amplifier have how many input terminals:
26. An operational amplifier will act as inverting amplifier, when the input signal is connected to:
27. At 0 K semi conductors are
28. Automatic functioning of streetlight can be done by the use of:
29. Base of the transistor is very thin of the order of
30. Conversion of alternating current into direct current is called:
31. Conversion of only one half of A.C. into D.C. is called
32. Depletion region carries
33. Depletion region has:
34. During negative half cycle of A.C then p n Junction offers.
35. Electrons present in P-type material due to thermal pair generation are:
36. Emitter base junction is always:
37. Find the gain if inverting, amplifier of external resistance R1 = 10KΩ and r² = 100K Ω
38. For normal operation of a transistor, the E-B junction is always
39. For rectification we use
40. Forward resistance of p-n junction is:
41. Gain of inverting op-amp in the R1=α and r²=0
42. Greater concentration of impurity is added in:
43. Hole is equivalent to:
44. Holes are exist in:
45. Identify which device used the rectification:
46. If a reverse current of a reverse biased junction is increased to a maximum value then:
47. If positive terminal of the battery is connected to n-type and negative terminal is connected to p type then diode is:
48. In a transistor which one is very thin:
49. In an n-type semi conductor there are:
50. In forward biased situation, as the biasing voltage is increased, the current:
51. In forward biasing, the value of resistance is
52. In full wave rectification, the output DC voltage is obtained across the load for:
53. In general, most of the electrical circuits make use of:
54. In half wave rectification, the output DC voltage is obtained across the load for:
55. In npn transistor current does not flow in the direction from
56. In n-p-n transistor, the current flows in the direction from:
57. In order that a transistor acts as switch, a larger positive potential is applied across its:
58. In photovoltaic cell, current is directly proportional to:
59. In pn junction, p-type end is basically referred as:
60. In p-n-p transistor, the current flows in the direction from:
61. In p-type substances, the minority carries are:
62. In reverse biased, the resistance offered by the p-n junction is of the order of:
63. In reverse biasing a p-n junction offers
64. In semi conductor diode the p-type end is usually referred as
65. In the transistor schematic symbol, the arrow is:
66. The process of turning an alternating current waveform into a direct current waveform is called:
67. Junction used as indicator in electronic circuits is:
68. LDR means
69. Light emitting diode based on:
70. Light emitting diodes (LED) are made from semi-conductors:
71. Majority charge carries in the P-type region of p-n-junction are:
72. Minority carriers in a p-type substances are:
73. Minority carries in n-type substances are:
74. Operational-amplifier has been discussed as comparator of:
75. Output resistance of an op-amp is
76. Photo diode can be used as:
77. Photo diode can turn its current on and off in
78. Photo voltaic cell is also called:
79. Photodiode detects
80. Photodiode is operated:
81. Photodiode is used for detection of heat
82. P-n junction when reversed biased acts as a:
83. PN-junction cannot be used as
84. Process of conversion of A.C. into D.C. is called
85. Pulsating output of full wave rectifier can be made smooth by using circuit called:
86. Reverse current flows due to
87. Reverse resistance of p-n junction is:
88. Semi conductor diode conducts only when it is:
89. Semi conductors with donor atoms and free electrons belong to the type:
90. Semi-conductor diode conducts only when it is
91. SI unit of current gain is:
92. Silicon is the most commonly used:
93. Temperature coefficient of resistivity of a semi conductor is:
94. The advantage of LEDs is:
95. The automatic working of street lights is due to
96. The average gap for Germanium at OK is:
97. The barrier potential of Silicon Diode at room temperature is:
98. The basic condition for a transistor amplifier circuit is:
99. The central region of a transistor is called
100. The central region of n-p-n transistor is known as:
101. The characteristic of transistor are:
102. The circuit of full wave rectification consist of:
103. The circuit which changes input signal at the output with a phase shift of 1800 is called
104. The circuit which compares the two voltages is
105. The color of light emitted by a LED depends on
106. The common door bell requires a voltage of about
107. The crystal of Germinium or silicon in its pure form at absolute zero acts as:
108. The crystal of germinium or silicon in its pure form at room temperature acts as:
109. The current gain ratio β of a transistor is given as
110. The diode cannot be used as
111. The diode used for the detection of visible and in visible light is:
112. The electronic circuit which gives the inversion of input signal at the output is called
113. The emitter and base has concentration of impurity:
114. The equation of voltage gain β of an amplifier can be expressed as
115. The external potential difference applied to p-n junction for forward biasing supplied energy to:
116. The forward current through a semi-conductor diode circuit is due to
117. The gain of the non-inverting amplifier can be expressed as
118. The gain of transistor amplifier depends upon
119. The impurity in the germanium is usually in the ratio of:
120. The input resistance of an op-amplifier is:
121. The light emitting diode emits light when it is:
122. The magnitude of open loop gain at room temperature is:
123. The magnitude of open loop gain of the operational amplifier is of the order of
124. The most commonly used diode for special purpose is:
125. The number of LEDs required to display all the digits is:
126. The number of terminals in a semiconductor diode is
127. The operational amplifier is:
128. The output of two inputs OR gate is 0 only when its
129. The photodiodes are used for:
130. The pn junction on forward biasing acts as:
131. The potential barrier for germanium at room temperature is
132. The potential barrier for silicon at room temperature is
133. The potential difference across depletion region in case of Ge is:
134. The potential difference across depletion region in case of Si is:
135. The potential difference develops in case of Ge is
136. The potential difference set up across the depletion region is called
137. The process due to which current flows only during alternate half cycle is known as:
138. The process of doping causes the resistivity of semi conductor to:
139. The pulsating output voltage of a rectifier can be made smooth by using a circuit known as:
140. The ratio B in transistor is called:
141. The reverse current through a semi-conductor diode circuit is due to
142. The semi conductor diode has the property of a:
143. The size of base in a transistor is
144. The specially designed semi conductor diodes used as indicator lamps in electronic circuits are:
145. The specially designed semi-conductor used for as fast countings in electronic circuits will be :
146. The term transistor stands for:
147. The thickness of the base is of the order of:
148. The transistor in a circuit basically acts as:
149. The use of LDR is in the circuit of:
150. The width of central region of a transistor is
151. The width of depletion region of a junction:
152. There is no current due to holes in good electrical conductors because they have:
153. To turn the transistor OFF, the base current is set:
154. Transistor can be used as:
155. Transistor was discovered by
156. Transistors are made from
157. Types of transistors are:
158. Universal gate is the gate which can perform the function of:
159. Usually VBB is:
160. When a p-n junction is reverse biased , the depletion region is
161. When a silicon crystal is doped with a pentavalent element, it becomes
162. When a transistor is used in a circuit generally:
163. When light emitting diode is forward biased, it emits light of colour:
164. When p-type of p-n-junction connected to positive end and N-type of the junction connected to the negative terminal of battery then the junction is:
165. When transistor works as an amplifier, its output is:
166. Which diode works at reverse biasing?
167. Which factor does not affect the conductivity of PN-junction diode:
168. Which of the followings is not basic operation of Boolean variable
169. Which one can be used as temperature sensor in electric circuit?
170. Which one of the following device based on p-n junction:
171. Which one of the following has smallest energy gap:
172. Which one of the following has the greatest energy gap:
173. Which one of the following is not semi conductor:
174. While drawing a graph between current and biasing voltage in p-n junction, the current is taken:
Short Questions
1. Define depletion region and biasing?
2. Define forward resistance of the p- n junction?
3. Describe anyone use of semi conductor diode?
4. Describe some important applications of photo diodes?
5. Describe the working principle of a LED?
6. Draw a circuit symbol of n-p-n transistor ?
7. Draw a circuit symbol of p-n-p transistor ?
8. Draw a neat diagram of an op- amp?
9. How does an op – amp act as a comparator?
10. How does the motion of an electron in a n- type substance differ from the motion of holes in a p- type substance?
11. How is a p- n junction formed?
12. How many diodes may be used for half wave rectification ?
13. How may types are of rectifications ?
14. How the conductor’s semi – conductors and insulators can be distinguished by bond theory of solids? Explain.
15. LDR stands for ?
16. Define forward resistance of the p-n junction ?
17. The inputs of a gate are 1 and o. identify the gate if its output is (a) 0 (b) 1?
18. What are important properties of semi conductor?
19. What are in holes in semi – conductor? Explain the electron hole pair generation?
20. What are N – type and p- types substance. Explain them?
21. What are semiconductors?
22. What are the advantages and disadvantages of the transistor over a vacuum tube?
23. What are the essential components required for rectification ?
24. What do LED and LASER stand for?
25. What do photo diodes? Point out their use.
26. What do you mean by forward biasing ?
27. What do you mean by reverse biasing ?
28. What do you understand by output resistance and input resistance of an op- amp?
29. What do you understand by saturation in operational amplifier?
30. What do you understand the electronics as a branch of physics?
31. What is a logic gate ?
32. What is a n-p-n transistor ?
33. What is a p-n junction ?
34. What is a p-n-p transistor ?
35. What is a transistor ?
36. What is an amplifier ?
37. What is an operational amplifier?
38. What is AND gate ?
39. What is biasing ?
40. What is Boolean algebra ?
41. What is depletion region ?
42. What is difference between a half – wave rectification and full wave rectification?
43. What is electronics ?
44. What is exclusive OR gate (XOR) ?
45. What is input resistance ?
46. What is meant by amplitude modulation? Explain how information is carried by electromagnetic wave?
47. What is meant by rectification?
48. What is meant by the current gain of a transistor?
49. What is meant for forwarding and reverse biasing of a semi – conductor diode?
50. What is NAND gate ?
51. What is NOT gate ?
52. What is n-type substance ?
53. What is open loop gain of an operational amplifier ?
54. What is open loop gain of an operational amplifier?
55. What is OR gate ?
56. What is output resistance ?
57. What is P- n junction (or semiconductor diode)?
58. What is p- n junction?
59. What is photovoltaic cell ?
60. What is potential barrier ?
61. What is potential barrier of germanium and silicon?
62. What is p-type substance ?
63. What is rectification?
64. What is solar cell (or photovoltaic cell)? Give its uses.
65. What is temperature? Draw symbols of p – n and n – p –n transistor?
66. What is the biasing requirement of the junction of a transistor? For its normal operation? Explain how these requirements are met in a common emitter amplifier?
67. What is the current gain of a transistor ?
68. What is the effect of forward and reverse biasing of a diode on the width of depletion region?
69. What is the function of a sensor ?
70. What is the net charge on n - type or a p - type substance?
71. What is the principle of virtual ground? Apply it to find the gain of an inverting amplifier?
72. What is the use of a photo diode ?
73. What is the voltage gin of a transistor ?
74. What is voltage gain of a transistor?
75. When a p-n junction is formed ?
76. Why a photo diode is operated in a reverse biased state?
77. Why charge carries are not present in the depletion region?
78. Why is a photo – diode operated in reverse biased state?
79. Why is the base current in a transistor very low ?
80. Why ordinary silicon diode does not emit light?
81. Write down some special kinds of diodes ?
82. Write some important uses of OP- amp?
83. Write some important uses of operational amplifier ?
84. Write the equation of a gain of a non – inverting amplifier?
Long Questions
1. What is p-n junction? Also describe forward biased and reverse biased p-n
2. What is meant by rectification? Explain the action of semi-conductor diode as half wave rectifier.
3. What are the specially designed p-n junction? What are the application of p-n junction?
4. How is it used as an amplifier? Give its circuit diagram. Deduce the relation for its voltage gain.
5. What is transistor? Explain its working.
6. How a transistor is used as a switch?
7. Explain operational amplifier.
8. Draw the circuit diagram of inverting amplifier and label it. Evaluate a relation for its gain.
9. Draw the circuit diagram of non-inverting amplifier and label it. Evaluate a relation for its gain.
10. Write a note on op-amp as a comparator.
11. Explain comparator as a night switch.
12. What is digital system?
13. Describe the fundamental logic gates.
"14. Draw the symbols of logic gates for the following Boolean functions. Write their respective truth labels.
NOR Gate, NAND Gate, Exclusive OR Gate , Exclusive-NOR Gate (XNOR), "
15. The current flowing into the base of a transistor is 100 micro Ampere. Find its collector current Ic. its emitter current Te and the ratio Ic/Ie, if the value of current gain β is 100.