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. A diode as a rectifier converts:

Low voltage to high voltage

High voltage to low voltage

A.C. into D.C.

D.C. into A.C.

2. Diode can work as

Oscillator

Rectifier

Multivibrator

Modulator

3. In semiconductors at a room temperature

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 and the conduction band is partially filled

The valence band is completely filled

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

Logic gates

Amplifier

Oscillator

Filter

5. The working of transistor as amplifier is similar to

Three diodes in common

Step down transformer

Triode vacuum tube

Step up transformer

6. Photovoltaic cell produces electrical energy from

Chemical energy

None of these

Heat energy

Light energy

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

Conductors

Insulators

Superconductors

Semiconductors

8. In insulators

Conduction band is partially filled with electrons

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

9. 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

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

Damaged

Works efficiently

Require more current

None of these

11. In a PN junction

High potential at N side and low potential at P side

High potential at P side and low potential at N side

P and N both are at same potential

Undetermined

12. 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

NOT gate

NOR gate

OR gate

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

Increased by reverse biasing

Is independent of voltage

Decreased by reverse biasing

Increased by forward biasing

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

None of these

Zero

High

Low

15. n-type semiconductor if formed

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

From pure Si crystal

16. Light emitting diode work when it is

None of these

Forward biases

Both

Reverse biased

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

Narrow

Infinity

Zero

Wide

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

Collector

Base

Emitter

Can be any of the above three

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

None of these

Free electrons

Valence electrons

Tightly bound electrons

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

Unit cell

Ore

All of these

Crystal lattice

21. Reverse bias applied on a junction diode

Increases the majority carrier current

Increase the minority carrier current

Raises the potential barrier

Lowers the potential barrier

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

Increase its electrical resistivity

Increase its electrical conductivity

Enable it to Telerate higher voltage

Increase its life

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

Magnification

Amplification

All of these

Rectification

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

None of these

Insulator

Semiconductor

Superconductor

25. 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

26. Reverse bias applied on a junction diode

Raises the potential barrier

Increases the majority carrier current

Lowers the potential barrier

Increase the minority carrier current

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

120° Phase shift

90° Phase shift

No Phase shift

180° Phase shift

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

Boron

All of these

Gallium

Aluminum

29. 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

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

Protons and electrons

Holes and electrons

Electrons and protons

Electrons and holes

31. In a P-type semiconductor

Major current carriers are mobile negative ions

Major current carriers are mobile holes

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

Major current carriers are electrons

32. In Germanium crystal, impurity donor elements have valiancy

33. When the output of OR gate is 1

If either input is zero

If both inputs are zero

Only if both inputs are 1

If either or both inputs are 1

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

Base

Collector

Any of the above depending on nature of transistor

Emitter

35. Symbol represents

NOT gate

XNOR gate

NAND gate

NOR gate

36. In a n-p-n transistor:

Negative charge moves from emitter to base

Holes move from emitter to base

Holes move from base to collector

Negative charge moves from collector to base

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

10¯¹² cm

1 mm

1 cm

10¯⁶ cm

38. 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

Non-inverting voltage at output

Virtual input

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

Almost zero

Zero

None of these

Infinity

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

NAND gate

AND gate

OR gate

NOT gate

41. 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

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

Zero amplitude

Unit amplitude

Constant amplitude

Variable amplitude

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

P-type semiconductor

N-type semiconductor

None of these

N-type conductor

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

Collector

Emitter

Can be any of the above three

Base

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

Extra electrons

Neutrons

Missing of electrons

Protons

46. In p-type semiconductor

Major current carrier is electrons

Major carrier is mobile holes

Major carrier is mobile negative ions

The number of mobile holes exceeds the number of acceptors

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

Force

Stress

Strain

None of these

48. Arsenic, antimony or phosphorus are impurities of

None of these

may be p-type or n-type

p-type

n-type

49. 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

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

p-type semiconductor

n-type conductor

p-type conductor

n-type semiconductor

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

4.9

9.8

52. At absolute zero, Si acts as

None of these

Non-metal

Metal

Insulator

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

Thousands

None of these

Hundreds

Man hundred

54. At absolute zero, Si acts as

Metal

Insulator

Non-metal

None of these

55. When n-type of semiconductor is heated,

Number of holes increases while that of holes decreases

Number of electrons increases while that of holes decreases

Number of electrons and holes remains same

Number of electrons and holes increases equally

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

Extrinsic

Intrinsic

n-type

p-type

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

Phosphorus

Aluminum

Boron

Gold

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

Emitter

Collector

None of these

Base

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

Amplifier

Rectifier

P-type material

Oscillator

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

Slightly less than emitter current

Greater than emitter current

Equal to emitter current

Any of above

61. Radio waves of constant amplitude can be generated with

Rectifier

Filter

FET

Oscillator

62. Which one is reverse-biased?

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

Minority carriers

Blockers

Dual carriers

Majority carriers

64. The number of junctions in the PNP transistor are

65. The energy band gap is maximum in

Insulators

Superconductors

Metals

Semiconductors

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

Lowers the potential barrier

Raises the potential barrier

Increase the majority carrier current

Increase the minority carrier current

67. Acceptor and donor impurities donate

p-carriers and n-carriers respectively

p-carriers only

n-carriers only

n-carriers and p-carriers respectively

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

Potential is maximum

Electric field is maximum

Electric field is zero

Potential is zero

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

n-type conductor

p-type conductor

p-type semiconductor

n-type semiconductor

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

Aluminum

Arsenic

Antimony

Phosphorus

71. Which one is forward bias?

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

Holes

None of these

Neutrons

Electrons

73. The forward resistance of the diode is

Many ohms

Ohms

Few ohms

None of these

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

None of these

Millisecond

Nanosecond

Microsecond

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

Conductor

Semiconductor

Alloy

Insulator

76. The thickness of the base is equal to

Mean of thickness of emitter and collector

Thickness of emitter

Very small as compared to the thickness of emitter and collector

Thickness of collector

77. LDR means:

None of these

Light dependent resistance

Low degree resistor

Low degree radiations

78. With negative feedback, the returning signal:

Is proportional to output current

Aids the input signal

Is proportional to differential voltage gain

Opposes the input signal

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

Phosphorus

Antimony

Arsenic

Aluminum

80. When NPN transistor is used as an amplifier

Electrons move from collector to base

Electrons move from base to emitter

Electrons move from emitter to base

Holes move from base to emitter

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

Extra electrons

Missing electrons

Protons

Neutrons

82. The critical temperature for mercury is

7.2 K

4.2 K

3.72 K

1.18 K

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

An amplifier

Filtering circuit

A rectifier

Converter

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

Remain fixed

Increases slowly

Decreases slowly

Suddenly increases

85. NAND gate is

Not a universal gate

A universal gate

A basic gate

A basic universal gate

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

Compress ional stress

Tensile stress

Shear stress

None of these

87. 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

Band levels

None of these

Forbidden energy states

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

AND gate

NOT gate

OR gate

XOR gate

89. Polythene, potystrene and nylon are examples of

Crystalline solids

Glassy solids

Polymeric solids

Amorphous solids

90. The positive sign of gain indicates that

Input and out signals are not in phase

Input and out signals are in phase

May be in phase or not

None of these

91. 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

None of these

Diode is neutralized

Diode is reverse biased

92. N-type crystal is

None of these

Positively charged

Negative charged

Neutral

93. To use a transistor as an amplifier

Both junctions are reverse biased

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

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

NAND gates

OR gates

NOT gates

AND gates

95. 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

It has low resistance to the current flow when forward biased

Its conductivity increases with rise of temperature

It has high resistance to the current flow when reverse biased

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

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

Electromagnetic Waves

Transverse Waves

Gamma Rays

x-rays

98. Young’s modulus for copper is

None of these

110 Nm¯²

91 x 10 Nm¯²

70 x 10 Nm¯²

99. 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

100. Photodiode is used for

Detection of light

None of these

Emission of light

Light display

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

Filter

Logic gates

Oscillator

Amplifier

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

Detector

Rectifier

Oscillator

None of these

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

Solar cells

The light emitting diode

The switch

The photo diodes

104. The operation of a transistor requires

That the collector be heated

That the emitter be heated

That the base be heated

None of these

105. A n-p-n transistor conducts when

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 negative with respect to the base

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

106. A NAND gate has:

None of these

LOW inputs and a HIGH output

HIGH inputs and a HIGH output

LOW inputs and a LOW output

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

Increase its life

Enable it to Telerate higher voltage

Increase its electrical resistivity

Increases its electrical conductivity

108. Which is normal used of transistor?

Rectifier

P-type material

Switching device

Diode

109. The least doped region in a transistor is

Base

Either emitter or collector

Collector

Emitter

110. The ratio β shows the

None of these

Input resistance

Voltage gain

Current gain

111. The ratio β represents

112. Which logic gate is represented by following diagram?

EOR

AND

NOR

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

Decreases

First A and B

Remains constant

Increases

114. The energy band gap is maximum in

Insulators

Semiconductors

Superconductors

Metals

115. Transistor can be used as

Full wave rectifier

Amplifier

Filter

Half wave rectifier

116. 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

117. In the transistor schematic symbol, the arrow

Is locate on the collector

Is located on the emitter

Is located on the base

Point from north to south

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

p-type

n-type

Intrinsic

Extrinsic

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

Computers

Transformers

Electric motors

Electric generations

120. Non-inverting amplifier circuits have

A low output impedance

A very high input impedance

None of these

A very low input impedance

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

Electrons move from base to collector

Holes move from base to emitter

Holes move from emitter to base

Holes move from emitter be base

122. Depletion region of a junction is formed

Under forward bias

Under reverse bias

When temperature varies

During the manufacturing process

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

Each of them decreases

Copper increases and germanium decreases

Copper decreases and germanium increases

Each of them increases

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

p-type

Superconductor

Insulator

n-type

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

Charged region

None of these

Depletion region

Diffusion region

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

Transistor

Diode

Amplifier

Rectifier

127. In Germanium crystal, impurity donor elements have valiancy

128. A substance which have empty conduction band is called

Insulator

None of these

Semiconductor

Conductor

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

Force

Stress

None of these

Strain

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

Or gates and NOT gates

OR gates only

AND gates and NOT gates

AND gates, OR gates, and NOT gates

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

OR gate

AND gate

Comparator

INVERTER gate

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

Very low

Very high

Almost negligible

Zero

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

Using a Coolidge tube

Using a transistor

Suppressing the harmonics in A.C voltage

Suppressing half wave of A.C supply by using diode

134. In a semiconductor, the mobility of holes is

Less than electrons

None

Greater than electrons

Equal to electrons

135. 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

Each of them decreases

Copper increases and germanium decreases

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

mix

any of above

137. 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

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

Resistance of copper decreases while that of germanium increases

Resistance of both increases

Resistance of copper increases while that of germanium decreases

Resistance of both decreases

139. Application of photodiode is/are

Automatic switching

Logic gates

None of these

Detection of visible and invisible radiations

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

None of these

Shear modulus

Young’s modulus

Bulk modulus

141. In insulators

Conduction band is filled with electrons and valence bad 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

142. 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

143. 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

Potential barrier in depletion layer remains unchanged

Diode is reverse biased

144. An OP-AMPs can amplify

Both A.C. & D.C.

A.C.

D.C.

None of these

145. Zener breakdown in a semiconductor diode occurs when

Potential barrier is reduced to zero

Reverse bias exceeds certain value

Forward current exceeds certain value

Forward bias exceeds certain value

146. In half wave rectification

Current flows in one directions

Current flows in pulses

None of these

Only half cycle is used

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

It offers a very low open loop gain all of above

It offers a very high inputs resistance to the input current

It offers a very low output resistance

None of these

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

Kilo ohms

Mega ohms

Several mega ohms

Ohms

149. Depletion layer consists of

Electrons

Immobile ions

Protons

Mobile ions

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

Inductor

Off switch

On switch

Capacitor

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

P-type material

N-type material

Super conductor

Semiconductor

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

4.9

9.8

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

Common emitter configuration

None of these

Common collector configuration

Common base configuration

154. In a P-type semiconductor

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

Major current carriers are mobile holes

Major current carriers are mobile negative ions

Major current carriers are electrons

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

Greater than one

Of zero

Less than one

Equal to one

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

To A.C.

In reverse bias

In forward bias

None of these

157. A transistor consists of

Three PN-junctions

One PN-junction

Four PN-junctions

Two PN-junctions

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

Missing electrons

Neutrons

Protons

Extra electrons

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

None of these

Modulus of electricity

Bulk’s modulus

Young’s modulus

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

Phosphorus

Indium

Antimony

Arsenic

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

Neutrons

Holes

Protons

Electrons

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

Large number of free electrons and few holes

Equal number of free electrons and holes

Large number of holes and electrons

Large number of holes and few electrons

163. Semi-conductor germanium and silicon are

Tetravalent

Trivalent

Divalent

Pentavalent

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

Base

Collector

Emitter

Any of above

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

Decreased by reverse biasing

Is independent of voltage

Increased by forward biasing

Increased by reverse biasing

166. The least doped region in a transistor is

Collector

Base

Emitter

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

All inputs are LOW

At least one input is LOW

At least one input is HIGH

All inputs are HIGH

168. In forward bias the width of potential barrier

No effect

Decreases

Increases

Remains same

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

Decreases

Remains unchanged

Increases

Decreases and then increases

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

p-type conductor

n-type semiconductor

n-type conductor

p-type semiconductor

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

Both are at the high potential

Inverting terminal is at high potential

Non-inverting terminal is at high potential

Both are at the same potential

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

Forward bias

Diode design

Doping density

Temperature

173. 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

Reversed biased

Zero biased

None of these

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

0.5 V

0.7 V

0.67 V

0.9 V

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

Gallium

Aluminum

All of above

Boron

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

Remains unchanged

Decreases

Decreases and then increases

Increases

177. Identify the correct statement about minority carriers

Free electrons in n-type and p-type

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

Holes in n-type and p-type

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

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

PMDC MDCAT Registration Online 2025 Last Date
MDCAT Test Schedule 2025 Dates Announced
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

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

MDCAT Biology Fields of Specialization Online Test MCQS

Prime Peshawar Entry Test Answer Key 2025 Result Merit Lists 1st, 2nd, 3rd

MDCAT English Vocabulary Online Test 1

LCMD Karachi Entry Test 2025 Preparations Online Mcqs

MDCAT Biology Reproduction Test Online

MDCAT Physics Alternating Current Test Online

Leave a Reply Cancel reply