Home/ECAT/ECAT Physics Electronics MCQS Online Test

ECAT Physics Electronics MCQS Online Test

Maan AliLast Updated: April 19, 2025

Physics Electronics MCQS Online Test

ECAT Physics Electronics Chapter Online Test

Total Questions:	177
Time Allowed:	60 Minutes
Total Marks:	177
How to Attempt Test:	Please choose the right Option in MCQ-type question.
Test Helpful For:	ECAT Entry Test Physics Online Test Interview Questions about Physics All Universities Entrance Test Recruitments Tests

Please wait...

1. The part of a transistor which is most heavily doped to produce large number of majority carriers is

Emitter

Collector

Can be any of the above three

Base

2. When we apply reverse bias to a junction diode, it

Increase the majority carrier current

Raises the potential barrier

Increase the minority carrier current

Lowers the potential barrier

3. The materials in which valence band and conduction band overlap are called

Conductors

Semiconductors

Superconductors

Insulators

4. In forward bias, the width of potential barrier in a p-n junction diode

Remains constant

Decreases

First A and B

Increases

5. Conversion of low input a.c. into high output a.c. is called:

Rectification

Magnification

Amplification

All of these

6. In a P-type semiconductor

Major current carriers are mobile holes

Major current carriers are electrons

Major current carriers are mobile negative ions

The no. of mobile holes exceeds the no. of mobile acceptors

7. A transistor consists of

Four PN-junctions

Three PN-junctions

One PN-junction

Two PN-junctions

8. The forward resistance of the diode is

Few ohms

None of these

Many ohms

Ohms

9. Semi-conductors with donor atoms and free electrons belong to the type

mix

any of above

10. A signal applied at the non-inverting input, of an O.P that appears after amplification at the output terminal, with

90° Phase shift

120° Phase shift

No Phase shift

180° Phase shift

11. Electrons present in p-type material due to thermal pair generation are

Minority carriers

Dual carriers

Majority carriers

Blockers

12. The logic gate that will have HIGH or “1” at its output when any one of its input if HIGH is a(n):

OR gate

NOR gate

NOT gate

AND gate

13. Semi-conductor germanium and silicon are

Pentavalent

Trivalent

Divalent

Tetravalent

14. The part of a transistor which is heavily doped to produce large number of majority carriers is

Any of the above depending on nature of transistor

Base

Collector

Emitter

15. When a pentavalent material like As, is added to tetravalent material l.e. Ge, we get a

P-type material

Super conductor

N-type material

Semiconductor

16. A junction between p-type material and n-type material is called as

Transistor

Amplifier

Diode

Rectifier

17. Zener breakdown in a semiconductor diode occurs when

Potential barrier is reduced to zero

Forward current exceeds certain value

Forward bias exceeds certain value

Reverse bias exceeds certain value

18. If positive end of battery is connected to p-side and negative end of battery is connected to n-side of diode then

Diode is forward biased

Diode is neutralized

Diode is reverse biased

None of these

19. Arsenic, antimony or phosphorus are impurities of

p-type

None of these

may be p-type or n-type

n-type

20. The ratio of tensile stress to tensile strain is called

Young’s modulus

Bulk’s modulus

Modulus of electricity

None of these

21. Suitable impurities are added to a semiconductor depending on its use. This is due to:

Increase its life

Increase its electrical resistivity

Increases its electrical conductivity

Enable it to Telerate higher voltage

22. In insulators

Valence band is partially filled with electrons

Conduction band is empty and valence band is filled with electrons

Conduction band is filled with electrons and valence band is empty

Conduction band is partially filled with electrons

23. The energy gap between conduction band and valence band is order 0.07 eV. It is a

Conductor

Alloy

Insulator

Semiconductor

24. Which logic gate is represented by following diagram?

AND

EOR

NOR

25. In the middle of the depletion layer of a reverse-biased p-n junction, the

Electric field is maximum

Electric field is zero

Potential is maximum

Potential is zero

26. Radio waves of constant amplitude can be generated with

Filter

FET

Rectifier

Oscillator

27. Acceptor and donor impurities donate

n-carriers and p-carriers respectively

p-carriers only

n-carriers only

p-carriers and n-carriers respectively

28. Young’s modulus for copper is

91 x 10 Nm¯²

None of these

70 x 10 Nm¯²

110 Nm¯²

29. The basic logic gate whose output is the complement of the input is the:

INVERTER gate

Comparator

AND gate

OR gate

30. In the p-type semi-conductor the majority and minority charge carriers are respectively

Electrons and protons

Holes and electrons

Electrons and holes

Protons and electrons

31. Transistors with various combinations are widely used as switches in:

Electric generations

Transformers

Computers

Electric motors

32. n-type germanium is obtained on doping intrinsic germanium with

Aluminum

Phosphorus

Gold

Boron

33. The output will be a LOW for any case when one or more inputs are zero in a(n):

OR gate

NOT gate

AND gate

NAND gate

34. At absolute zero, Si acts as

None of these

Non-metal

Metal

Insulator

35. Output voltage in full wave rectification is not smooth. In order to have smooth output voltage

None of these

Capacitor is used

Solvent is used

Resistor is used

36. To obtain a p-type germanium semiconductor, it must be doped with

Indium

Phosphorus

Antimony

Arsenic

37. Photodiode is used for

Detection of light

Emission of light

Light display

None of these

38. The units of modulus of elasticity are same as that of

None of these

Stress

Strain

Force

39. The least doped region in a transistor is

Emitter

Base

Collector

Either emitter or collector

40. The part of a transistor which is most heavily doped to produce large number of majority carriers is

Collector

Emitter

Base

Can be any of the above three

41. Reverse bias applied on a junction diode

Increase the minority carrier current

Increases the majority carrier current

Lowers the potential barrier

Raises the potential barrier

42. In the transistor schematic symbol, the arrow

Is located on the emitter

Is locate on the collector

Point from north to south

Is located on the base

43. In Germanium crystal, impurity donor elements have valiancy

44. The p-n junction diode works as insulator, if connected

In forward bias

To A.C.

None of these

In reverse bias

45. The width of a depletion layer in a p-n junction is

Is independent of voltage

Increased by reverse biasing

Increased by forward biasing

Decreased by reverse biasing

46. The number of junctions in the PNP transistor are

47. n-type semiconductor if formed

From pure Si crystal

From pure Ge crystal

When a Ge crystal is doped with an impurity containing 5 valence electrons

When a Ge crystal is doped with an impurity containing 3 valence electrons

48. When a semiconductor is continuously heated, then value of its resistance

Decreases and then increases

Increases

Decreases

Remains unchanged

49. When a semiconductor is continuously heated, then value of its resistance

Decreases and then increases

Increases

Decreases

Remains unchanged

50. A non-inverting closed-loop op-amp circuit generally has a gain factor:

Less than one

Of zero

Greater than one

Equal to one

51. A piece of copper and another of germanium are cooled from room temperature to 77 K, the resistance of

Each of them increases

Copper decreases and germanium increases

Copper increases and germanium decreases

Each of them decreases

52. The ratio β represents

53. If p-type material of the PN-junction is connected with positive terminal of the battery and n-type material with negative terminal of the battery, it is said to be

Forward biased

None of these

Reversed biased

Zero biased

54. The semiconductor diode can be used as a rectifier because _

It has low resistance to the current flow when forward biased & high resistance when reverse biased

Its conductivity increases with rise of temperature

It has low resistance to the current flow when forward biased

It has high resistance to the current flow when reverse biased

55. The impurity atoms with which a pure silicon should be doped to make a p-type semiconductor is

Antimony

Phosphorus

Aluminum

Arsenic

56. A device which converts an alternating current to direct current is called

Oscillator

P-type material

Amplifier

Rectifier

57. N-type crystal is

Neutral

Negative charged

None of these

Positively charged

58. A photodiode can turn its current ON and OFF in

Millisecond

Microsecond

Nanosecond

None of these

59. In a p-type semiconductor germanium is doped with:

All of above

Aluminum

Boron

Gallium

60. In a n-p-n transistor:

Negative charge moves from collector to base

Holes move from base to collector

Negative charge moves from emitter to base

Holes move from emitter to base

61. Non-inverting amplifier circuits have

A very low input impedance

None of these

A very high input impedance

A low output impedance

62. Copper and germanium are cooled to 70 K from room temperature, then

Resistance of both increases

Resistance of both decreases

Resistance of copper increases while that of germanium decreases

Resistance of copper decreases while that of germanium increases

63. Due to high loop gain of the amplifier, the inverting and non-inverting inputs are

Inverting terminal is at high potential

Both are at the high potential

Both are at the same potential

Non-inverting terminal is at high potential

64. The critical temperature for mercury is

3.72 K

7.2 K

4.2 K

1.18 K

65. A device for converting an alternating current into a pulsating from or direct current is known as

Oscillator

Rectifier

Detector

None of these

66. In a p-type semiconductor germanium is doped with:

All of these

Boron

Gallium

Aluminum

67. When aluminum is added as an impurity to silicon, then resulting material is

p-type semiconductor

p-type conductor

n-type semiconductor

n-type conductor

68. A n-p-n transistor conducts when

Collector is positive and emitter is negative with respect to the base

Collector is positive and emitter is at negative potential as the base

Both collector and emitter are negative with respect to the base

Both collector and emitter are positive with respect to the base

69. LDR means:

None of these

Low degree radiations

Low degree resistor

Light dependent resistance

70. When the output of OR gate is 1

If both inputs are zero

If either or both inputs are 1

If either input is zero

Only if both inputs are 1

71. With negative feedback, the returning signal:

Opposes the input signal

Is proportional to output current

Is proportional to differential voltage gain

Aids the input signal

72. When the conductivity of a semiconductor is only due, to breaking of covalent bonds, the semiconductor is called

p-type

Extrinsic

n-type

Intrinsic

73. The potential difference across the depletion region of silicon is

0.67 V

0.9 V

0.7 V

0.5 V

74. Reverse bias applied on a junction diode

Lowers the potential barrier

Raises the potential barrier

Increase the minority carrier current

Increases the majority carrier current

75. In n-type substances, the minority carriers are

Holes

Electrons

Neutrons

None of these

76. A diode as a rectifier converts:

D.C. into A.C.

A.C. into D.C.

High voltage to low voltage

Low voltage to high voltage

77. The transistor provide good power amplification when they are used in

Common base configuration

Common collector configuration

None of these

Common emitter configuration

78. Symbol represents

XNOR gate

NAND gate

NOT gate

NOR gate

79. The especially designed semiconductor diodes used as indicator lamps in electronic circuits are

The photo diodes

The light emitting diode

Solar cells

The switch

80. When n-p-n transistor is used as an amplifier

Holes move from emitter to base

Holes move from emitter be base

Holes move from base to emitter

Electrons move from base to collector

81. The energy band gap is maximum in

Semiconductors

Insulators

Superconductors

Metals

82. When Ge crystal is doped with phosphorus atom, then it becomes

Superconductor

n-type

p-type

Insulator

83. In a good conductor, the energy gap between the conduction band and the valence band is

Infinity

Wide

Narrow

Zero

84. Which of the following is not characteristic of an op—amp

It offers a very high inputs resistance to the input current

None of these

It offers a very low open loop gain all of above

It offers a very low output resistance

85. Diode can work as

Multivibrator

Oscillator

Rectifier

Modulator

86. In a junction diode, the holes are due to

Protons

Extra electrons

Neutrons

Missing of electrons

87. p-n junction when reversed biased acts as a

Off switch

Capacitor

Inductor

On switch

88. In junction diode, the holes are because of:

Protons

Neutrons

Extra electrons

Missing electrons

89. In the middle of the depletion layer of a reverse-biased p-n junction, the

Electric field is maximum

Potential is maximum

Potential is zero

Electric field is zero

90. When the conductivity of a semiconductor is only due to breaking of covalent bonds, the semiconductor is called

Extrinsic

p-type

Intrinsic

n-type

91. Identify the correct statement about minority carriers

Free electrons in n-type and p-type

Holes in n-type and free electrons in p-type

Free electrons in n-type and holes in p-type

Holes in n-type and p-type

92. At room temperature, a p-type semi-conductor has

Large number of holes and electrons

Equal number of free electrons and holes

Large number of holes and few electrons

Large number of free electrons and few holes

93. NAND gate is

A universal gate

A basic gate

Not a universal gate

A basic universal gate

94. When a p-n junction diode is reverse biased, the flow of current across the junction is mainly due to

Depends upon the nature of material

Drift of charges

Diffusion of charges

Both drift and diffusion of charges

95. When arsenic is added as an impurity to silicon, the resulting material is

None of these

N-type conductor

P-type semiconductor

N-type semiconductor

96. Barrier potential of a p-n junction diode does not depend on:

Diode design

Forward bias

Doping density

Temperature

97. Depletion layer consists of

Immobile ions

Protons

Mobile ions

Electrons

98. When NPN transistor is used as an amplifier

Electrons move from collector to base

Electrons move from emitter to base

Holes move from base to emitter

Electrons move from base to emitter

99. In Germanium crystal, impurity donor elements have valiancy

100. When a strength changes the length of a body, it is called

Compress ional stress

None of these

Tensile stress

Shear stress

101. In common emitter amplifier (l₀/lE) = 0.98, then current gain is

9.8

4.9

102. The measure of deformation of a solid when stress is applied to it is called

Force

Strain

None of these

Stress

103. In comma emitter amplifier (l₀/lE) = 0.98, then current gain is

9.8

4.9

104. In p – n junction, after diffusion, a charge less region is formed around the junction is called

None of these

Charged region

Diffusion region

Depletion region

105. In n-p-n transistor, p works as

Any of above

Collector

Base

Emitter

106. In insulators

Conduction band is empty and valence band is filled with electrons

Conduction band is filled with electrons and valence bad is empty

Conduction band is partially filled with electrons

Valence band is partially filled with electrons

107. The electrical circuit used to bet smooth DC output from a rectifier circuit is called

Amplifier

Filter

Oscillator

Logic gates

108. In a PN junction

P and N both are at same potential

High potential at N side and low potential at P side

Undetermined

High potential at P side and low potential at N side

109. Suitable impurities are added to a semiconductor depending on its use. This is due to

Increase its electrical conductivity

Increase its life

Enable it to Telerate higher voltage

Increase its electrical resistivity

110. The gain A of the amplifier is of the order of

Hundreds

Thousands

None of these

Man hundred

111. On increasing the reverse bias to a large value in a p-n junction diode current

Remain fixed

Suddenly increases

Decreases slowly

Increases slowly

112. An OP-AMP comparator is a circuit that compares the signal voltage on one of its inputs with a _

Virtual input

Reference voltage on the other

Non-inverting voltage at output

Output

113. The ratio β shows the

Input resistance

None of these

Current gain

Voltage gain

114. Polythene, potystrene and nylon are examples of

Crystalline solids

Amorphous solids

Polymeric solids

Glassy solids

115. When aluminum is added as an impurity to silicon, then resulting material is

p-type conductor

n-type semiconductor

p-type semiconductor

n-type conductor

116. In semiconductors at a room temperature

The valence band is completely filled and the conduction band is partially filled

The conduction band is completely empty

The valence band is partially empty and the conduction band is partially filled

The valence band is completely filled

117. In p-type semi-conductor, the majority charge carriers are

Electrons

Neutrons

Protons

Holes

118. At room temperature, a p-type semi-conductor has

Large number of holes and electrons

Large number of free electrons and few holes

Equal number of free electrons and holes

Large number of holes and few electrons

119. What input values will cause an AND logic gate to produce a HIGH output?

At least one input is LOW

At least one input is HIGH

All inputs are HIGH

All inputs are LOW

120. If a signal passing through a gate is inhibited by sending a low into one of the inputs, and the output is HIGH, the gate is a(n):

NAND

NOR

AND

121. In forward bias the width of potential barrier

Decreases

Increases

No effect

Remains same

122. The device or circuit used for conversion of A.C. into D.C. is called

Filtering circuit

A rectifier

Converter

An amplifier

123. When n-p-n transistor is used as an amplifier,

Electrons move from base to collector

Holes move from emitter to base

Holes move from base to emitter

Holes move from emitter to base

124. A NAND gate has:

HIGH inputs and a HIGH output

LOW inputs and a HIGH output

None of these

LOW inputs and a LOW output

125. A substance which have empty conduction band is called

None of these

Conductor

Insulator

Semiconductor

126. When no light is incident on photodiode, the reverse current is

Very low

Zero

Very high

Almost negligible

127. The positive sign of gain indicates that

Input and out signals are not in phase

None of these

May be in phase or not

Input and out signals are in phase

128. In p-type semiconductor

The number of mobile holes exceeds the number of acceptors

Major carrier is mobile holes

Major current carrier is electrons

Major carrier is mobile negative ions

129. The thickness of the base is equal to

Mean of thickness of emitter and collector

Thickness of collector

Thickness of emitter

Very small as compared to the thickness of emitter and collector

130. The least doped region in a transistor is

Collector

Base

Emitter

131. The working of transistor as amplifier is similar to

Three diodes in common

Triode vacuum tube

Step down transformer

Step up transformer

132. Transistor can be used as

Filter

Full wave rectifier

Half wave rectifier

Amplifier

133. Exclusive-OR (XOR) logic gates can be constructed from what other logic gates?

AND gates and NOT gates

Or gates and NOT gates

AND gates, OR gates, and NOT gates

OR gates only

134. The switch is open when the resistance between C and E becomes

Almost zero

Infinity

None of these

Zero

135. The width of a depletion layer in a p-n junction is

Is independent of voltage

Decreased by reverse biasing

Increased by reverse biasing

Increased by forward biasing

136. Which of the following when added as an impurity into the silicon produces n-type semi-conductor?

137. At absolute zero, Si acts as

Non-metal

Metal

None of these

Insulator

138. In a n-p-n transistor:

Negative charge moves from emitter to base

Holes move from base to collector

Negative charge moves from collector to base

Holes move from emitter to base

139. The whole structure obtained by the repetition of unit cell is known as

All of these

Crystal lattice

Unit cell

Ore

140. A diode as a rectifier converts:

High voltage to low voltage

Low voltage to high voltage

A.C. into D.C.

D.C. into A.C.

141. A pieced of copper and another of germanium are cooled from room temperature to 77 K, the resistance of

Copper decreases and germanium increases

Each of them increases

Copper increases and germanium decreases

Each of them decreases

142. A p-n junction has a thickness of the order of:

1 mm

10¯⁶ cm

1 cm

10¯¹² cm

143. The energy band gap is maximum in

Semiconductors

Superconductors

Metals

Insulators

144. The part of a transistor, which is heavily doped to produce a large number of majority carriers, is

Emitter

None of these

Collector

Base

145. Application of photodiode is/are

Automatic switching

None of these

Detection of visible and invisible radiations

Logic gates

146. In reverse biasing of p-n junction, the resistance offered by the diode is of the order of

Mega ohms

Ohms

Several mega ohms

Kilo ohms

147. In junction diode, the holes are because of:

Extra electrons

Protons

Missing electrons

Neutrons

148. A single transistor can be used to build which of the following digital logic gates?

NOT gates

OR gates

NAND gates

AND gates

149. In a semiconductor, the mobility of holes is

Equal to electrons

Less than electrons

None

Greater than electrons

150. The electrical circuit used to have smooth DC output from a rectifier circuit is called

Logic gates

Oscillator

Amplifier

Filter

151. An OP-AMPs can amplify

D.C.

None of these

A.C.

Both A.C. & D.C.

152. The ratio of applied stress to volumetric strain is called

Shear modulus

None of these

Bulk modulus

Young’s modulus

153. The simplest type of rectification known as half wave rectification is obtained by

Using a Coolidge tube

Using a transistor

Suppressing half wave of A.C supply by using diode

Suppressing the harmonics in A.C voltage

154. In half wave rectification

Only half cycle is used

Current flows in pulses

None of these

Current flows in one directions

155. In semiconductors at a room temperature

The valence band is partially empty and the conduction band is partially filled

The valence band is completely filled and the conduction band is partially filled

The valence band is completely filled

The conduction band is completely empty

156. Which one is forward bias?

157. The impurity atoms with which a pure silicon should be doped to make a p-type semiconductor is

Antimony

Arsenic

Phosphorus

Aluminum

158. The operation of a transistor requires

That the emitter be heated

That the base be heated

That the collector be heated

None of these

159. Using OP-Amp as an inverting amplifier, the non-inverting terminal has potential

High

Zero

Low

None of these

160. Due to the break down the p-n junction suffers

Require more current

Works efficiently

Damaged

None of these

161. When n-type of semiconductor is heated,

Number of holes increases while that of holes decreases

Number of electrons and holes remains same

Number of electrons and holes increases equally

Number of electrons increases while that of holes decreases

162. When an alternating accelerating field is applied to a charge it produces

x-rays

Electromagnetic Waves

Gamma Rays

Transverse Waves

163. Two inputs of NAND gates are shorted. This gate is equivalent to

OR gate

XOR gate

AND gate

NOT gate

164. Which is normal used of transistor?

Switching device

Rectifier

P-type material

Diode

165. In between two consecutive permissible energy bands, there is a range of energy states which cannot be occupied by electrons. These are called

Forbidden energy states

Band levels

None of these

Hidden energy states

166. Which one is reverse-biased?

167. p-type crystal of a p-n junction diode is connected to a positive terminal of battery and n-type crystal connected to negative terminal of battery

Potential barrier in depletion layer increases

Potential barrier in depletion layer remains unchanged

Diode is forward based

Diode is reverse biased

168. In a P-type semiconductor

Major current carriers are electrons

Major current carriers are mobile holes

The no. of mobile holes exceeds the no. of mobile acceptors

Major current carriers are mobile negative ions

169. Depletion region of a junction is formed

Under forward bias

When temperature varies

During the manufacturing process

Under reverse bias

170. When boron is added as an impurity to silicon, the resulting material is:

n-type conductor

p-type conductor

p-type semiconductor

n-type semiconductor

171. The electromagnetic waves emitted by the LC circuit of areal to a transmitting station are of

Variable amplitude

Zero amplitude

Unit amplitude

Constant amplitude

172. The electrons in the outermost shell of an atom are called

Valence electrons

Free electrons

None of these

Tightly bound electrons

173. To use a transistor as an amplifier

No bias voltages are required

Both junctions are forward biased

The emitter base junction is forward biased and the base collector junction is reverse biased

Both junctions are reverse biased

174. If on increasing temperature the resistance decreases, then it is

Insulator

None of these

Superconductor

Semiconductor

175. Light emitting diode work when it is

Forward biases

None of these

Both

Reverse biased

176. In p-n-p transistor the collector current is

Equal to emitter current

Slightly less than emitter current

Any of above

Greater than emitter current

177. Photovoltaic cell produces electrical energy from

None of these

Heat energy

Chemical energy

Light energy

You Can Learn and Gain more Knowledge through our Online Quiz and Testing system Just Search your desired Preparation subject at Gotest.

UET Peshawar Entry Test 2025 Registration Online ETEA Test D...
ECAT Statistics Test Set 17
ECAT Statistics Test Set 16
ECAT Statistics Test Set 15
ECAT Statistics Test Set 14
ECAT Statistics Test Set 13
ECAT Statistics Test Set 12
ECAT Statistics Test Set 11
ECAT Statistics Test Set 10
ECAT Statistics Test Set 9

Maan AliLast Updated: April 19, 2025

Facebook Twitter Reddit WhatsApp Share via Email Print

3 Comments

khansa noreen says:

September 11, 2020 at 10:12 pm

i want to know that how I prepare my entry test?

Name (required) says:

June 30, 2017 at 10:25 pm

assalam o alaikum mot of the answers are wrong…kindly check it

1. Humza arain says:
  
  January 7, 2021 at 4:27 pm
  
  Humza arain

ECAT Physics Electronics MCQS Online Test

Physics Electronics MCQS Online Test

ECAT Physics Electronics Chapter Online Test

You Might Also Like

Maan Ali

3 Comments

Leave a Reply Cancel reply

Physics Electronics MCQS Online Test

ECAT Physics Electronics Chapter Online Test

You Might Also Like

Maan Ali

Your Related

ECAT Chemistry Solutions Online Test

ECAT English Antonyms Online Test

ECAT Chemistry Alcohols Phenols And Ethers Test Online

ECAT Computer Science Data Basics Test Online

ECAT Computer Getting Started with “C” Test Online

ECAT English Analogy 2 Online Test

3 Comments

Leave a Reply Cancel reply