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

NOT gate

NOR gate

OR gate

AND gate

2. Photodiode is used for

None of these

Light display

Detection of light

Emission of light

3. The energy band gap is maximum in

Metals

Superconductors

Insulators

Semiconductors

4. 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

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

None of these

Oscillator

Detector

Rectifier

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

Magnification

Rectification

All of these

Amplification

7. A n-p-n transistor conducts when

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

Both collector and emitter are negative with respect to the base

Both collector and emitter are positive with respect to the base

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

8. Depletion layer consists of

Electrons

Mobile ions

Immobile ions

Protons

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

Modulus of electricity

Young’s modulus

Bulk’s modulus

None of these

10. With negative feedback, the returning signal:

Opposes the input signal

Aids the input signal

Is proportional to differential voltage gain

Is proportional to output current

11. In a P-type semiconductor

Major current carriers are mobile holes

Major current carriers are electrons

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

Major current carriers are mobile negative ions

12. NAND gate is

A universal gate

A basic universal gate

Not a universal gate

A basic gate

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

Oscillator

Logic gates

Amplifier

Filter

14. A diode as a rectifier converts:

A.C. into D.C.

Low voltage to high voltage

High voltage to low voltage

D.C. into A.C.

15. Reverse bias applied on a junction diode

Increase the minority carrier current

Lowers the potential barrier

Increases the majority carrier current

Raises the potential barrier

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

None of these

Young’s modulus

Bulk modulus

Shear modulus

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

Is independent of voltage

Increased by forward biasing

Decreased by reverse biasing

Increased by reverse biasing

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

Can be any of the above three

Collector

Base

Emitter

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

Greater than emitter current

Equal to emitter current

Slightly less than emitter current

Any of above

20. Polythene, potystrene and nylon are examples of

Amorphous solids

Glassy solids

Polymeric solids

Crystalline solids

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

Large number of holes and electrons

Large number of holes and few electrons

Equal number of free electrons and holes

Large number of free electrons and few holes

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

Narrow

Infinity

Wide

Zero

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

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

Common emitter configuration

Common collector configuration

None of these

Common base configuration

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

At least one input is HIGH

At least one input is LOW

All inputs are HIGH

All inputs are LOW

26. Diode can work as

Multivibrator

Rectifier

Modulator

Oscillator

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

Decreases slowly

Suddenly increases

Increases slowly

Remain fixed

28. Acceptor and donor impurities donate

p-carriers and n-carriers respectively

n-carriers and p-carriers respectively

p-carriers only

n-carriers only

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

Strain

Force

None of these

Stress

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

AND gates

NAND gates

OR gates

NOT gates

31. In insulators

Conduction band is partially filled with electrons

Conduction band is filled with electrons and valence band is empty

Valence band is partially filled with electrons

Conduction band is empty and valence band is filled with electrons

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

Holes move from base to emitter

Holes move from emitter be base

Holes move from emitter to base

Electrons move from base to collector

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

Dual carriers

Blockers

Majority carriers

Minority carriers

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

Base

Collector

Emitter

Can be any of the above three

35. In a n-p-n transistor:

Negative charge moves from collector to base

Negative charge moves from emitter to base

Holes move from base to collector

Holes move from emitter to base

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

Transformers

Electric generations

Electric motors

Computers

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

Increase its electrical resistivity

Enable it to Telerate higher voltage

Increase its life

Increase its electrical conductivity

38. In a P-type semiconductor

Major current carriers are electrons

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

Major current carriers are mobile negative ions

Major current carriers are mobile holes

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

Filter

Logic gates

Oscillator

Amplifier

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

Phosphorus

Aluminum

Arsenic

Antimony

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

Emitter

None of these

Base

Collector

42. In a n-p-n transistor:

Holes move from emitter to base

Negative charge moves from collector to base

Negative charge moves from emitter to base

Holes move from base to collector

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

OR gate

AND gate

XOR gate

NOT gate

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

Zero amplitude

Variable amplitude

Constant amplitude

Unit amplitude

45. In a semiconductor, the mobility of holes is

Greater than electrons

None

Less than electrons

Equal to electrons

46. In p-type semiconductor

The number of mobile holes exceeds the number of acceptors

Major carrier is mobile negative ions

Major carrier is mobile holes

Major current carrier is electrons

47. In semiconductors at a room temperature

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

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

48. 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

Both drift and diffusion of charges

Drift of charges

Diffusion of charges

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

Reference voltage on the other

Output

Virtual input

Non-inverting voltage at output

50. The ratio β shows the

Input resistance

Current gain

None of these

Voltage gain

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

Missing electrons

Neutrons

Extra electrons

Protons

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

Valence electrons

None of these

Tightly bound electrons

Free electrons

53. Semi-conductor germanium and silicon are

Pentavalent

Tetravalent

Divalent

Trivalent

54. 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 remains unchanged

Diode is forward based

Diode is reverse biased

Potential barrier in depletion layer increases

55. LDR means:

Low degree radiations

None of these

Low degree resistor

Light dependent resistance

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

Kilo ohms

Ohms

Mega ohms

Several mega ohms

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

Boron

Gold

Aluminum

Phosphorus

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

Insulator

Semiconductor

None of these

Superconductor

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

Semiconductor

Insulator

Alloy

Conductor

60. When n-type of semiconductor is heated,

Number of electrons increases while that of holes decreases

Number of electrons and holes increases equally

Number of holes increases while that of holes decreases

Number of electrons and holes remains same

61. Which logic gate is represented by following diagram?

EOR

NOR

AND

62. In insulators

Conduction band is empty and valence band is filled with electrons

Conduction band is partially filled with electrons

Conduction band is filled with electrons and valence bad is empty

Valence band is partially filled with electrons

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

N-type conductor

None of these

N-type semiconductor

P-type semiconductor

64. 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

65. The ratio β represents

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

Collector

Base

Emitter

Any of the above depending on nature of transistor

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

p-type semiconductor

n-type semiconductor

p-type conductor

n-type conductor

68. At absolute zero, Si acts as

None of these

Non-metal

Metal

Insulator

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

n-type

Extrinsic

Intrinsic

p-type

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

Crystal lattice

Unit cell

All of these

Ore

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

Comparator

INVERTER gate

AND gate

OR gate

72. Non-inverting amplifier circuits have

A very low input impedance

A low output impedance

A very high input impedance

None of these

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

Almost zero

Zero

Infinity

None of these

74. Which one is reverse-biased?

75. Transistor can be used as

Amplifier

Filter

Full wave rectifier

Half wave rectifier

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

First A and B

Remains constant

Decreases

Increases

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

Increase the minority carrier current

Raises the potential barrier

Lowers the potential barrier

Increase the majority carrier current

78. A transistor consists of

Two PN-junctions

Four PN-junctions

Three PN-junctions

One PN-junction

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

Forward bias

Temperature

Diode design

Doping density

80. n-type semiconductor if formed

From pure Si 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

From pure Ge crystal

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

Greater than one

Of zero

Less than one

Equal to one

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

Thousands

None of these

Man hundred

Hundreds

83. A piece 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 decreases

Each of them increases

Copper increases and germanium decreases

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

p-type conductor

n-type conductor

n-type semiconductor

p-type semiconductor

85. The thickness of the base is equal to

Mean of thickness of emitter and collector

Thickness of collector

Very small as compared to the thickness of emitter and collector

Thickness of emitter

86. Which is normal used of transistor?

Rectifier

P-type material

Switching device

Diode

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

0.67 V

0.5 V

0.7 V

0.9 V

88. The operation of a transistor requires

That the emitter be heated

None of these

That the base be heated

That the collector be heated

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

1 cm

10¯¹² cm

10¯⁶ cm

1 mm

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

Antimony

Aluminum

Arsenic

Phosphorus

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

Superconductors

Insulators

Conductors

Semiconductors

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

Stress

Force

None of these

Strain

93. The number of junctions in the PNP transistor are

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

OR gates only

AND gates, OR gates, and NOT gates

Or gates and NOT gates

AND gates and NOT gates

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

It has high resistance to the current flow when reverse biased

It has low resistance to the current flow when forward biased

Its conductivity increases with rise of temperature

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

96. At absolute zero, Si acts as

Metal

None of these

Insulator

Non-metal

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

Electric field is zero

Electric field is maximum

Potential is zero

Potential is maximum

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

Copper increases and germanium decreases

Copper decreases and germanium increases

Each of them increases

Each of them decreases

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

Capacitor is used

Solvent is used

Resistor is used

None of these

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

Electrons

Neutrons

Protons

Holes

101. In Germanium crystal, impurity donor elements have valiancy

102. The least doped region in a transistor is

Either emitter or collector

Emitter

Base

Collector

103. Zener breakdown in a semiconductor diode occurs when

Forward bias exceeds certain value

Reverse bias exceeds certain value

Forward current exceeds certain value

Potential barrier is reduced to zero

104. A NAND gate has:

LOW inputs and a HIGH output

HIGH inputs and a HIGH output

None of these

LOW inputs and a LOW output

105. N-type crystal is

Neutral

None of these

Negative charged

Positively charged

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

Resistance of both decreases

Resistance of copper increases while that of germanium decreases

Resistance of both increases

Resistance of copper decreases while that of germanium increases

107. A diode as a rectifier converts:

A.C. into D.C.

D.C. into A.C.

Low voltage to high voltage

High voltage to low voltage

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

All of these

Aluminum

Boron

Gallium

109. Young’s modulus for copper is

91 x 10 Nm¯²

None of these

70 x 10 Nm¯²

110 Nm¯²

110. Which one is forward bias?

111. 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

112. The positive sign of gain indicates that

None of these

May be in phase or not

Input and out signals are in phase

Input and out signals are not in phase

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

Compress ional stress

Shear stress

Tensile stress

None of these

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

No Phase shift

120° Phase shift

180° Phase shift

90° Phase shift

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

Gamma Rays

Transverse Waves

x-rays

Electromagnetic Waves

116. In forward bias the width of potential barrier

Increases

No effect

Remains same

Decreases

117. Symbol represents

XNOR gate

NAND gate

NOR gate

NOT gate

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

It offers a very low open loop gain all of above

None of these

It offers a very low output resistance

It offers a very high inputs resistance to the input current

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

Charged region

Diffusion region

None of these

Depletion region

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

p-type semiconductor

n-type semiconductor

p-type conductor

n-type conductor

121. Light emitting diode work when it is

Forward biases

Reverse biased

Both

None of these

122. In a PN junction

Undetermined

High potential at N side and low potential at P side

P and N both are at same potential

High potential at P side and low potential at N side

123. 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

Holes in n-type and p-type

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

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

The switch

The photo diodes

Solar cells

The light emitting diode

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

Neutrons

Extra electrons

Missing electrons

Protons

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

Decreases and then increases

Decreases

Increases

Remains unchanged

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

Increased by reverse biasing

Increased by forward biasing

Decreased by reverse biasing

Is independent of voltage

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

None of these

Electrons

Holes

Neutrons

129. To use a transistor as an amplifier

No bias voltages are required

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

Both junctions are forward biased

Both junctions are reverse biased

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

Increases

Decreases and then increases

Remains unchanged

Decreases

131. A substance which have empty conduction band is called

None of these

Insulator

Conductor

Semiconductor

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

9.8

4.9

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

Diode

Rectifier

Amplifier

Transistor

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

mix

any of above

135. The least doped region in a transistor is

Emitter

Base

Collector

136. The critical temperature for mercury is

7.2 K

3.72 K

4.2 K

1.18 K

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

Large number of holes and few electrons

Large number of holes and electrons

Equal number of free electrons and holes

Large number of free electrons and few holes

138. Photovoltaic cell produces electrical energy from

Chemical energy

Heat energy

Light energy

None of these

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

Both are at the same potential

Inverting terminal is at high potential

Both are at the high potential

Non-inverting terminal is at high potential

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

Phosphorus

Arsenic

Antimony

Indium

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

Any of above

Emitter

Collector

Base

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

Using a Coolidge tube

Suppressing half wave of A.C supply by using diode

Using a transistor

Suppressing the harmonics in A.C voltage

143. An OP-AMPs can amplify

None of these

A.C.

Both A.C. & D.C.

D.C.

144. The working of transistor as amplifier is similar to

Three diodes in common

Step down transformer

Triode vacuum tube

Step up transformer

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

Filtering circuit

A rectifier

An amplifier

Converter

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

Protons

Extra electrons

Neutrons

Missing of electrons

147. The energy band gap is maximum in

Superconductors

Metals

Semiconductors

Insulators

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

Electrons and holes

Electrons and protons

Holes and electrons

Protons and electrons

149. In semiconductors at a room temperature

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 and the conduction band is partially filled

The valence band is completely filled

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

N-type material

Super conductor

P-type material

Semiconductor

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

Amplifier

Oscillator

Rectifier

P-type material

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

Millisecond

None of these

Microsecond

Nanosecond

153. Application of photodiode is/are

None of these

Automatic switching

Logic gates

Detection of visible and invisible radiations

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

Holes move from emitter to base

Electrons move from base to collector

Holes move from base to emitter

Holes move from emitter to base

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

Almost negligible

Very low

Zero

Very high

156. Arsenic, antimony or phosphorus are impurities of

None of these

may be p-type or n-type

n-type

p-type

157. When the output of OR gate is 1

If both inputs are zero

If either input is zero

If either or both inputs are 1

Only if both inputs are 1

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

9.8

4.9

159. In the transistor schematic symbol, the arrow

Is located on the base

Is locate on the collector

Is located on the emitter

Point from north to south

160. Depletion region of a junction is formed

Under forward bias

During the manufacturing process

When temperature varies

Under reverse bias

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

Capacitor

Off switch

Inductor

On switch

162. When NPN transistor is used as an amplifier

Electrons move from base to emitter

Electrons move from collector to base

Electrons move from emitter to base

Holes move from base to emitter

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

p-type

Intrinsic

Extrinsic

n-type

164. 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

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

Require more current

Damaged

None of these

Works efficiently

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

Zero

High

None of these

Low

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

In reverse bias

In forward bias

To A.C.

None of these

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

Hidden energy states

None of these

Band levels

Forbidden energy states

169. In Germanium crystal, impurity donor elements have valiancy

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

NOT gate

OR gate

AND gate

NAND gate

171. Reverse bias applied on a junction diode

Increase the minority carrier current

Raises the potential barrier

Increases the majority carrier current

Lowers the potential barrier

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

p-type

Insulator

n-type

Superconductor

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

Boron

All of above

Gallium

Aluminum

174. The forward resistance of the diode is

None of these

Few ohms

Many ohms

Ohms

175. 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 neutralized

None of these

Diode is reverse biased

Diode is forward biased

176. Radio waves of constant amplitude can be generated with

Oscillator

Rectifier

Filter

FET

177. In half wave rectification

Current flows in one directions

Only half cycle is used

Current flows in pulses

None of these

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 Digital Computer Fundamentals Online Test

Quaid-e-Azam University QAU Nawab Shah ECAT Chemistry Preparation Entry Test Online

ECAT English Correction Test Online

ECAT English Spotting Errors Test 11 Online

ECAT Mathematics Differentiation Online Test

ECAT Physics Circular Motion Online Test

3 Comments

Leave a Reply Cancel reply