Home/MDCAT/MDCAT Physics Electronics Test Online

MDCAT Physics Electronics Test Online

Malik TahirLast Updated: May 26, 2025

Physics Electronics MCQS Online Test

MDCAT 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:	MDCAT Entry Test Physics Online Test Interview Questions about Physics All Universities Entrance Test Recruitments Tests

Please wait...

1. With negative feedback, the returning signal:

Aids the input signal

Is proportional to output current

Is proportional to differential voltage gain

Opposes the input signal

2. Depletion layer consists of

Protons

Electrons

Immobile ions

Mobile ions

3. A n-p-n transistor conducts when

Both collector and emitter are positive with respect to the base

Both collector and emitter are negative with respect to the base

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

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

4. 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

5. In insulators

Conduction band is filled with electrons and valence band is empty

Valence band is partially filled with electrons

Conduction band is partially filled with electrons

Conduction band is empty and valence band is filled with electrons

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

Resistance of both decreases

Resistance of both increases

Resistance of copper decreases while that of germanium increases

Resistance of copper increases while that of germanium decreases

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

Electric field is zero

Potential is maximum

Potential is zero

Electric field is maximum

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

Detector

None of these

Oscillator

Rectifier

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

Increased by forward biasing

Is independent of voltage

Increased by reverse biasing

Decreased by reverse biasing

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

Reference voltage on the other

Virtual input

Output

Non-inverting voltage at output

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

OR gates only

Or gates and NOT gates

AND gates and NOT gates

AND gates, OR gates, and NOT gates

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

Ore

Unit cell

All of these

Crystal lattice

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

Zero

Infinity

None of these

Almost zero

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

XOR gate

AND gate

NOT gate

OR gate

15. N-type crystal is

None of these

Neutral

Negative charged

Positively charged

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

Protons

Extra electrons

Missing electrons

Neutrons

17. Reverse bias applied on a junction diode

Increases the majority carrier current

Raises the potential barrier

Lowers the potential barrier

Increase the minority carrier current

18. Depletion region of a junction is formed

During the manufacturing process

When temperature varies

Under reverse bias

Under forward bias

19. 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

20. The working of transistor as amplifier is similar to

Step up transformer

Three diodes in common

Step down transformer

Triode vacuum tube

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

Common emitter configuration

Common collector configuration

None of these

Common base configuration

22. Photodiode is used for

Emission of light

Detection of light

None of these

Light display

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

Electrons

Protons

Neutrons

Holes

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

Enable it to Telerate higher voltage

Increase its life

Increases its electrical conductivity

Increase its electrical resistivity

25. The thickness of the base is equal to

Thickness of collector

Very small as compared to the thickness of emitter and collector

Mean of thickness of emitter and collector

Thickness of emitter

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

Tensile stress

None of these

Compress ional stress

Shear stress

27. Arsenic, antimony or phosphorus are impurities of

p-type

may be p-type or n-type

None of these

n-type

28. Light emitting diode work when it is

None of these

Reverse biased

Forward biases

Both

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

Emitter

Base

Collector

Can be any of the above three

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

Minority carriers

Blockers

Dual carriers

Majority carriers

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

n-type

p-type

Extrinsic

Intrinsic

32. 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

33. The energy band gap is maximum in

Metals

Superconductors

Insulators

Semiconductors

34. 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

Diode is reverse biased

Diode is forward biased

None of these

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

Any of above

Collector

Base

Emitter

36. The ratio β shows the

Input resistance

Voltage gain

None of these

Current gain

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

AND gate

OR gate

NOT gate

NAND gate

38. In a PN junction

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

Undetermined

39. 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):

AND

NOR

NAND

40. 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

41. To use a transistor as an amplifier

Both junctions are forward biased

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

No bias voltages are required

Both junctions are reverse biased

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

Phosphorus

Boron

Aluminum

Gold

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

Non-inverting terminal is at high potential

Both are at the high potential

Both are at the same potential

Inverting terminal is at high potential

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

Resistor is used

None of these

Capacitor is used

Solvent is used

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

n-type semiconductor

p-type semiconductor

p-type conductor

n-type conductor

46. Identify the correct statement about minority carriers

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

Free electrons in n-type and p-type

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

Both drift and diffusion of charges

Drift of charges

Depends upon the nature of material

Diffusion of charges

48. 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

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

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

0.67 V

0.9 V

0.5 V

0.7 V

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

p-type

Extrinsic

n-type

Intrinsic

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

N-type material

P-type material

Semiconductor

Super conductor

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

At least one input is LOW

All inputs are HIGH

All inputs are LOW

At least one input is HIGH

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

Infinity

Wide

Narrow

Zero

55. n-type semiconductor if formed

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

From pure Si crystal

From pure Ge crystal

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

56. The least doped region in a transistor is

Collector

Base

Emitter

57. Which one is reverse-biased?

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

Electrons move from base to collector

Holes move from emitter be base

Holes move from base to emitter

Holes move from emitter to base

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

OR gate

AND gate

Comparator

INVERTER gate

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

Variable amplitude

Zero amplitude

Unit amplitude

Constant amplitude

61. A diode as a rectifier converts:

D.C. into A.C.

High voltage to low voltage

A.C. into D.C.

Low voltage to high voltage

62. 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 conduction band is completely empty

The valence band is completely filled

63. Reverse bias applied on a junction diode

Lowers the potential barrier

Increases the majority carrier current

Increase the minority carrier current

Raises the potential barrier

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

Conductors

Semiconductors

Insulators

Superconductors

65. Symbol represents

NOR gate

NOT gate

XNOR gate

NAND gate

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

4.9

9.8

67. LDR means:

Light dependent resistance

Low degree radiations

Low degree resistor

None of these

68. In a semiconductor, the mobility of holes is

None

Less than electrons

Equal to electrons

Greater than electrons

69. 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 high inputs resistance to the input current

It offers a very low output resistance

70. In semiconductors at a room temperature

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

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

The conduction band is completely empty

The valence band is completely filled

71. The operation of a transistor requires

None of these

That the collector be heated

That the base be heated

That the emitter be heated

72. In half wave rectification

Only half cycle is used

None of these

Current flows in one directions

Current flows in pulses

73. 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

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

Increases

Decreases and then increases

Remains unchanged

Decreases

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

Indium

Phosphorus

Antimony

Arsenic

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

Protons

Missing of electrons

Extra electrons

Neutrons

77. In insulators

Conduction band is empty and valence band is filled with electrons

Valence band is partially filled with electrons

Conduction band is filled with electrons and valence bad is empty

Conduction band is partially filled with electrons

78. In Germanium crystal, impurity donor elements have valiancy

79. 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

Emitter

Base

Collector

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

Decreases and then increases

Increases

Decreases

Remains unchanged

81. 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

82. Radio waves of constant amplitude can be generated with

Filter

Rectifier

FET

Oscillator

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

1 cm

1 mm

10¯¹² cm

10¯⁶ cm

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

Transistor

Diode

Rectifier

Amplifier

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

Insulator

Alloy

Semiconductor

Conductor

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

High

None of these

Zero

Low

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

None of these

Valence electrons

Free electrons

Tightly bound electrons

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

Transverse Waves

Gamma Rays

Electromagnetic Waves

x-rays

89. A NAND gate has:

LOW inputs and a LOW output

HIGH inputs and a HIGH output

LOW inputs and a HIGH output

None of these

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

Enable it to Telerate higher voltage

Increase its electrical conductivity

Increase its life

Increase its electrical resistivity

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

In forward bias

None of these

In reverse bias

To A.C.

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

OR gates

AND gates

NOT gates

NAND gates

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

Boron

Gallium

Aluminum

All of these

94. 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

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

None of these

Semiconductor

Superconductor

Insulator

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

Depletion region

Charged region

Diffusion region

None of these

97. In p-type semiconductor

Major carrier is mobile negative ions

Major current carrier is electrons

Major carrier is mobile holes

The number of mobile holes exceeds the number of acceptors

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

Oscillator

P-type material

Rectifier

Amplifier

99. Transistor can be used as

Amplifier

Filter

Full wave rectifier

Half wave rectifier

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

It has high resistance to the current flow when reverse biased

Its conductivity increases with rise of temperature

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

It has low resistance to the current flow when forward biased

101. Which is normal used of transistor?

Diode

P-type material

Switching device

Rectifier

102. A transistor consists of

Three PN-junctions

Four PN-junctions

Two PN-junctions

One PN-junction

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

Forward bias

Doping density

Temperature

Diode design

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

None of these

Stress

Force

Strain

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

Arsenic

Antimony

Phosphorus

Aluminum

106. Zener breakdown in a semiconductor diode occurs when

Forward bias exceeds certain value

Potential barrier is reduced to zero

Forward current exceeds certain value

Reverse bias exceeds certain value

107. Application of photodiode is/are

None of these

Logic gates

Automatic switching

Detection of visible and invisible radiations

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

Filter

Oscillator

Amplifier

Logic gates

109. The forward resistance of the diode is

None of these

Few ohms

Many ohms

Ohms

110. In a n-p-n transistor:

Holes move from base to collector

Holes move from emitter to base

Negative charge moves from emitter to base

Negative charge moves from collector to base

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

Require more current

Damaged

None of these

Works efficiently

112. In Germanium crystal, impurity donor elements have valiancy

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

Large number of free electrons and few holes

Large number of holes and electrons

Large number of holes and few electrons

Equal number of free electrons and holes

114. 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 decreases

Each of them increases

Copper increases and germanium decreases

115. The critical temperature for mercury is

1.18 K

4.2 K

3.72 K

7.2 K

116. Which one is forward bias?

117. Young’s modulus for copper is

110 Nm¯²

91 x 10 Nm¯²

None of these

70 x 10 Nm¯²

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

Zero

Almost negligible

Very high

Very low

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

None of these

Band levels

Hidden energy states

Forbidden energy states

120. The positive sign of gain indicates that

Input and out signals are not in phase

May be in phase or not

Input and out signals are in phase

None of these

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

Shear modulus

Bulk modulus

None of these

Young’s modulus

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

Magnification

Amplification

Rectification

All of these

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

Increased by forward biasing

Decreased by reverse biasing

Is independent of voltage

Increased by reverse biasing

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

Extra electrons

Protons

Neutrons

Missing electrons

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

Suddenly increases

Increases slowly

Decreases slowly

Remain fixed

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

180° Phase shift

90° Phase shift

No Phase shift

120° Phase shift

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

All of above

Aluminum

Gallium

Boron

128. NAND gate is

A universal gate

A basic gate

A basic universal gate

Not a universal gate

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

A rectifier

Converter

An amplifier

Filtering circuit

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

Each of them decreases

Copper decreases and germanium increases

Each of them increases

Copper increases and germanium decreases

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

4.9

9.8

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

N-type semiconductor

P-type semiconductor

N-type conductor

None of these

133. The number of junctions in the PNP transistor are

134. The energy band gap is maximum in

Semiconductors

Insulators

Superconductors

Metals

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

Nanosecond

Millisecond

None of these

Microsecond

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

p-type

n-type

Insulator

Superconductor

137. An OP-AMPs can amplify

Both A.C. & D.C.

D.C.

None of these

A.C.

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

Potential is maximum

Electric field is zero

Potential is zero

Electric field is maximum

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

Greater than emitter current

Slightly less than emitter current

Equal to emitter current

Any of above

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

Using a transistor

Suppressing the harmonics in A.C voltage

Suppressing half wave of A.C supply by using diode

Using a Coolidge tube

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

Electrons

None of these

Neutrons

Holes

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

Raises the potential barrier

Increase the majority carrier current

Lowers the potential barrier

Increase the minority carrier current

143. Photovoltaic cell produces electrical energy from

Light energy

Heat energy

None of these

Chemical energy

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

Modulus of electricity

Young’s modulus

Bulk’s modulus

None of these

145. Which logic gate is represented by following diagram?

EOR

NOR

AND

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

Aluminum

Antimony

Arsenic

Phosphorus

147. When the output of OR gate is 1

If either or both inputs are 1

If both inputs are zero

If either input is zero

Only if both inputs are 1

148. Non-inverting amplifier circuits have

None of these

A very low input impedance

A very high input impedance

A low output impedance

149. At absolute zero, Si acts as

Non-metal

None of these

Metal

Insulator

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

None of these

Man hundred

Thousands

Hundreds

151. When n-type of semiconductor is heated,

Number of electrons and holes remains same

Number of electrons and holes increases equally

Number of holes increases while that of holes decreases

Number of electrons increases while that of holes decreases

152. 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

None of these

Zero biased

Forward biased

Reversed biased

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

Emitter

Base

None of these

Collector

154. In forward bias the width of potential barrier

No effect

Remains same

Increases

Decreases

155. 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

Diode is forward based

Potential barrier in depletion layer increases

Diode is reverse biased

Potential barrier in depletion layer remains unchanged

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

Electric generations

Computers

Electric motors

Transformers

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

Oscillator

Amplifier

Logic gates

Filter

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

mix

any of above

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

Of zero

Less than one

Greater than one

Equal to one

160. In a n-p-n transistor:

Holes move from emitter to base

Holes move from base to collector

Negative charge moves from emitter to base

Negative charge moves from collector to base

161. The ratio β represents

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

Capacitor

On switch

Inductor

Off switch

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

Ohms

Mega ohms

Several mega ohms

Kilo ohms

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

AND gate

OR gate

NOR gate

NOT gate

165. Semi-conductor germanium and silicon are

Pentavalent

Tetravalent

Divalent

Trivalent

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

Stress

None of these

Strain

Force

167. Polythene, potystrene and nylon are examples of

Glassy solids

Crystalline solids

Amorphous solids

Polymeric solids

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

Solar cells

The switch

The photo diodes

The light emitting diode

169. The least doped region in a transistor is

Base

Emitter

Either emitter or collector

Collector

170. At absolute zero, Si acts as

Non-metal

Insulator

Metal

None of these

171. Acceptor and donor impurities donate

n-carriers only

p-carriers only

n-carriers and p-carriers respectively

p-carriers and n-carriers respectively

172. A substance which have empty conduction band is called

None of these

Semiconductor

Insulator

Conductor

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

Increases

Remains constant

Decreases

First A and B

174. 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

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

Protons and electrons

Electrons and protons

Electrons and holes

Holes and electrons

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

n-type semiconductor

p-type conductor

p-type semiconductor

n-type conductor

177. Diode can work as

Modulator

Multivibrator

Rectifier

Oscillator

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

MDCAT Physics Vactors And Equilibrium Online Test
MDCAT Fundamental Concepts of Chemistry Test Online MCQs
MDCAT Biology Inheritance Test Online MCQs
MDCAT Biology Acellular life Test Online
MDCAT Biology Variety of Life Test Online MCQs
MDCAT Biology Fields of Specialization Online Test MCQS
MDCAT Biology Kingdom of Protista Online Test MCQS
MDCAT Biology Fungi Online Test MCQS
MDCAT Biology Kingdom Plantae Test Online MCQS
MDCAT Biology Gaseous Exchange Online Test MCQS

Malik TahirLast Updated: May 26, 2025

Facebook Twitter Reddit WhatsApp Share via Email Print

MDCAT Physics Electronics Test Online

Physics Electronics MCQS Online Test

MDCAT Physics Electronics Chapter Online Test

You Might Also Like

Malik Tahir

Leave a Reply Cancel reply

Physics Electronics MCQS Online Test

MDCAT Physics Electronics Chapter Online Test

You Might Also Like

Malik Tahir

Your Related

FMDC Islamabad Entry Test 2025 Dates Time Schedule Registration Form

MDCAT Biology Biodiversity Test Online MCQs

Sindh Medical Universities MDCAT Test Result 2025 Answer Keys

MDCAT English Vocabulary Online Test 1

Sharif Medical College Lahore Admission 2025 Registration Online Last Date

MDCAT Chemistry Alkyl Halides Test Online

Leave a Reply Cancel reply