ICS Part 2 Physics Chapter 18 Short Questions Preparation

12th Class Physics
Short Questions Preparation

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Chapter 12
Chapter 13
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Chapter 15
Chapter 16
Chapter 17
Chapter 18
Chapter 19
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Online Short Questions For Chapter 7 "ICS Part 2 Physics Chapter 18 Short Questions Preparation "

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Physics - ICS Part 2 Physics Chapter 18 Short Questions Preparation

Question # 1

Why is the photodiode operated in reverse biased state?

Ans 1: Photodiode is used for the detection of light.So it is used in reverse biased state.Reverse current increase with the intensity of incident light.When no light incidents,then reverse current will be negligible.

Question # 2

How is p-n junction formed?

Ans 1: A p-n junction is formed when a crystal of germanium or silicon is grown in such a way that is its one half is doped with a trivalent impurity and the other half with a pentavalent impurity.

Question # 3

How the normal operation of transistor is achieved?

Ans 1: For the normal operation the base emitter junction of transistor is forward biased and collector base junction is reverse.
In a common emitter amplifier ,input signal is applied between base and emitter and output signal is taken across collector and emitter,Similarly emitter base junction is forward biased and collector base junction is reverse biased.

Question # 4

What is the role of potential barrier in a diode?How it is formed in diode?

Ans 1: At the formation of pn-junction ,the free electrons in n-region because of their random motion diffuse into the p-region,.As a result of this diffusion a region is formed around the junction consisting of positive and negative ions,Due to charge on these ions a potential difference develops across the depletion region,This potential difference is called potential barrier,stops further diffusion of electron into the p-region.

Question # 5

Define logic system and logic gates.

Ans 1: A digital system deals with the quantities or variable which have only two discrete values or state.
The electronic circuits which implements the various logic operation are known as logic gates.

Question # 6

Why the biasing requirement of the junction of a transistor for its normal operation?

Ans 1: For the normal operation the base emitter junction of transistor is forward biased and collector base junction is reverse biased.

Question # 7

What is photodiode?Write down its two main applications.

Ans 1: Photodiode is used for the detection of light.It is used in reverse biased state.Reverse current increase with the intensity of incident light.When no light incidents then reverse current will be negligble.It is used as
1. Detection of both visible and and invisible radiations
2. Automatic switching

Question # 8

Write a note on LED.

Ans 1: Light emitting diode are made from the special semiconductor such as gallium arsenide and gallium arsenide phosphide in which the potential barrier between p and n side is such that when electrons combines with a hole during forward biased conduction,a photon of visible light is emitted.
LED are used in 7-segment display,small light sources etc.

Question # 9

Give two applications of gated in control system.

Ans 1: Gates are widely used in control system.They control the function of the system by monitoring some physical parameters such as temperature ,pressure or some other physical quantity of the system,Sensors are required to operate gates.

Question # 10

What is the potential barrier?What is the value of potential barrier of SI and Ge?

Ans 1: The potential difference across the depletion region which acts as a barrier to the flow of charge carriers is called potential barrier.The value of potential barrier for germanium is 0.3V and for silicon is 0.7 V.

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Prepare Complete Set Wise Questions For Chapter 7 "ICS Part 2 Physics Chapter 18 Short Questions Preparation "

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Set 2

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Set 3

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ICS Part 2 Physics Chapter 18 Short Questions Preparation - Set 1

Question # 1

Why is the photodiode operated in reverse biased state?

Ans 1: Photodiode is used for the detection of light.So it is used in reverse biased state.Reverse current increase with the intensity of incident light.When no light incidents,then reverse current will be negligible.

Question # 2

How is p-n junction formed?

Ans 1: A p-n junction is formed when a crystal of germanium or silicon is grown in such a way that is its one half is doped with a trivalent impurity and the other half with a pentavalent impurity.

Question # 3

How the normal operation of transistor is achieved?

Ans 1: For the normal operation the base emitter junction of transistor is forward biased and collector base junction is reverse.
In a common emitter amplifier ,input signal is applied between base and emitter and output signal is taken across collector and emitter,Similarly emitter base junction is forward biased and collector base junction is reverse biased.

Question # 4

What is the role of potential barrier in a diode?How it is formed in diode?

Ans 1: At the formation of pn-junction ,the free electrons in n-region because of their random motion diffuse into the p-region,.As a result of this diffusion a region is formed around the junction consisting of positive and negative ions,Due to charge on these ions a potential difference develops across the depletion region,This potential difference is called potential barrier,stops further diffusion of electron into the p-region.

Question # 5

Define logic system and logic gates.

Ans 1: A digital system deals with the quantities or variable which have only two discrete values or state.
The electronic circuits which implements the various logic operation are known as logic gates.

Question # 6

Why the biasing requirement of the junction of a transistor for its normal operation?

Ans 1: For the normal operation the base emitter junction of transistor is forward biased and collector base junction is reverse biased.

Question # 7

What is photodiode?Write down its two main applications.

Ans 1: Photodiode is used for the detection of light.It is used in reverse biased state.Reverse current increase with the intensity of incident light.When no light incidents then reverse current will be negligble.It is used as
1. Detection of both visible and and invisible radiations
2. Automatic switching

Question # 8

Write a note on LED.

Ans 1: Light emitting diode are made from the special semiconductor such as gallium arsenide and gallium arsenide phosphide in which the potential barrier between p and n side is such that when electrons combines with a hole during forward biased conduction,a photon of visible light is emitted.
LED are used in 7-segment display,small light sources etc.

Question # 9

Give two applications of gated in control system.

Ans 1: Gates are widely used in control system.They control the function of the system by monitoring some physical parameters such as temperature ,pressure or some other physical quantity of the system,Sensors are required to operate gates.

Question # 10

What is the potential barrier?What is the value of potential barrier of SI and Ge?

Ans 1: The potential difference across the depletion region which acts as a barrier to the flow of charge carriers is called potential barrier.The value of potential barrier for germanium is 0.3V and for silicon is 0.7 V.

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ICS Part 2 Physics Chapter 18 Short Questions Preparation - Set 2

Question # 1

Why the base current is transistor is very small?

Ans 1: Base is very thin so a number of electrons attracted by collector and very few enter into the base.And base current is very small.

Question # 2

Why charge carriers are not present in the depletion region?

Ans 1: This is due to the fact when an electron from an n region diffuses into the p-region,it leaves behind a positive ion.When this electron recombines with the hole in the p-region,a negative ion is formed,So no charge carrier are available in this region,though it contains immobile positive and negative ions.

Question # 3

What is photodiode?Write down its two main applications.

Ans 1: Photodiode is used for the detection of light.It is used in reverse biased state.Reverse current increase with the intensity of incident light.When no light incidents then reverse current will be negligble.It is used as
1. Detection of both visible and and invisible radiations
2. Automatic switching

Question # 4

Define current of gain of a transistor

Ans 1: The ratio of output current to input current is called current gain of a transistor.The ratio of collector current to base current is called current gain of a transistor.

Question # 5

What is the role of potential barrier in a diode?How it is formed in diode?

Ans 1: At the formation of pn-junction ,the free electrons in n-region because of their random motion diffuse into the p-region,.As a result of this diffusion a region is formed around the junction consisting of positive and negative ions,Due to charge on these ions a potential difference develops across the depletion region,This potential difference is called potential barrier,stops further diffusion of electron into the p-region.

Question # 6

How the normal operation of transistor is achieved?

Ans 1: For the normal operation the base emitter junction of transistor is forward biased and collector base junction is reverse.
In a common emitter amplifier ,input signal is applied between base and emitter and output signal is taken across collector and emitter,Similarly emitter base junction is forward biased and collector base junction is reverse biased.

Question # 7

Give four application or uses of photodiode?

Ans 1: It is used as
1. Detection of both visible and invisible radiations.
2. Logic circuits
3. Automatic switching
4. Optical communication equipment

Question # 8

Give any two characteristics of operational amplifier.

Ans 1: Input Resistance: It is the resistance between the + and - input of the amplifier,Whose value is of the order of several mega ohms.
Output resistance:It is the resistance between the output terminal and ground.Its value is only a few ohms.

Question # 9

How the current flows in forward and reverse biased diode?

Ans 1: In forward biasing,the external potential difference supplies energy to free electrons in n-region and holes in p-region to overcome the potential barrier,a current of the orderof a few milli-amperes begins to flow across the pn junction.
In reverse biasing ,no current flow due to the majority charge carrier,However a very small current of the order of of few micro amperes flow across the junction due to minority charge carriers.It is also known as reverse current or leakage current.

Question # 10

How is p-n junction formed?

Ans 1: A p-n junction is formed when a crystal of germanium or silicon is grown in such a way that is its one half is doped with a trivalent impurity and the other half with a pentavalent impurity.

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ICS Part 2 Physics Chapter 18 Short Questions Preparation - Set 3

Question # 1

What is meant by rectification?

Ans 1: The conversing of alternating current signal into pulsating direct current signal is called rectification.The current for this purpose is called rectifier circuit.

Question # 2

Differentiate between the forward biased and the reserve biase.

Ans 1: When p side is positive and n-side is negative,the diode is forward biased.The width of depletion region reduces to which more current is allowed to flow across the junction.The forward resistance is few ohms.
Ans 2: When p side is negative and n side is positive,the diode is reserved biased.The width of depletion region is increased and a very small current flows across the junction due to flow of minority charges carriers,The resistance offered by the diode is several mega ohms.

Question # 3

Give two applications of gated in control system.

Ans 1: Gates are widely used in control system.They control the function of the system by monitoring some physical parameters such as temperature ,pressure or some other physical quantity of the system,Sensors are required to operate gates.

Question # 4

How the normal operation of transistor is achieved?

Ans 1: For the normal operation the base emitter junction of transistor is forward biased and collector base junction is reverse.
In a common emitter amplifier ,input signal is applied between base and emitter and output signal is taken across collector and emitter,Similarly emitter base junction is forward biased and collector base junction is reverse biased.

Question # 5

Give any two characteristics of operational amplifier.

Ans 1: Input Resistance: It is the resistance between the + and - input of the amplifier,Whose value is of the order of several mega ohms.
Output resistance:It is the resistance between the output terminal and ground.Its value is only a few ohms.

Question # 6

How does the motion of an electron in n type substance differ from the motion of holes in a p type substance?

Ans 1: more mobile and rapid than holes in p-type substance because electrons do not require holes for their motions but p-type substance because electrons do not require holes for their motion but hole depend upon electrons for their motion,Both move in opposite direction.

Question # 7

What is OP-GATE?

Ans 1: OR-GATE implements the logic of OR operation.It has two or more inputs and a single output.Its output will be zero only when all the inputs are zero.

Question # 8

How the current flows in forward and reverse biased diode?

Ans 1: In forward biasing,the external potential difference supplies energy to free electrons in n-region and holes in p-region to overcome the potential barrier,a current of the orderof a few milli-amperes begins to flow across the pn junction.
In reverse biasing ,no current flow due to the majority charge carrier,However a very small current of the order of of few micro amperes flow across the junction due to minority charge carriers.It is also known as reverse current or leakage current.

Question # 9

Define Depletion region?

Ans 1: A region in a semiconductor device,usually at the junction of p-type and n-type materials ,in which there is neither an excess of electrons nor of holes is called depletion region,It charge less region.

Question # 10

The anode of a diode is 0.2V positive with respect to the cathode,It it forward biased?

Ans 1: Yes when anode is 0.2V positive with respect to cathode,it is forward biased.But the value of potential barrier for germanium is 0.3 V and for silicon is 0.7 V.Therefore there will be no conduction of current.

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ICS Part 2 Physics Chapter 18 Short Questions Preparation

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ICS Part 2 Physics Chapter 18 Short Questions Preparation

12th Class PhysicsShort Questions Preparation

12th Class Physics Chapter Wise Preparation

Online Short Questions For Chapter 7 "ICS Part 2 Physics Chapter 18 Short Questions Preparation "

Physics - ICS Part 2 Physics Chapter 18 Short Questions Preparation

Why is the photodiode operated in reverse biased state?

How is p-n junction formed?

How the normal operation of transistor is achieved?

What is the role of potential barrier in a diode?How it is formed in diode?

Define logic system and logic gates.

Why the biasing requirement of the junction of a transistor for its normal operation?

What is photodiode?Write down its two main applications.

Write a note on LED.

Give two applications of gated in control system.

What is the potential barrier?What is the value of potential barrier of SI and Ge?

Prepare Complete Set Wise Questions For Chapter 7 "ICS Part 2 Physics Chapter 18 Short Questions Preparation "

Set 1

Set 2

Set 3

ICS Part 2 Physics Chapter 18 Short Questions Preparation - Set 1

Why is the photodiode operated in reverse biased state?

How is p-n junction formed?

How the normal operation of transistor is achieved?

What is the role of potential barrier in a diode?How it is formed in diode?

Define logic system and logic gates.

Why the biasing requirement of the junction of a transistor for its normal operation?

What is photodiode?Write down its two main applications.

Write a note on LED.

Give two applications of gated in control system.

What is the potential barrier?What is the value of potential barrier of SI and Ge?

ICS Part 2 Physics Chapter 18 Short Questions Preparation - Set 2

Why the base current is transistor is very small?

Why charge carriers are not present in the depletion region?

What is photodiode?Write down its two main applications.

Define current of gain of a transistor

What is the role of potential barrier in a diode?How it is formed in diode?

How the normal operation of transistor is achieved?

Give four application or uses of photodiode?

Give any two characteristics of operational amplifier.

How the current flows in forward and reverse biased diode?

How is p-n junction formed?

ICS Part 2 Physics Chapter 18 Short Questions Preparation - Set 3

What is meant by rectification?

Differentiate between the forward biased and the reserve biase.

Give two applications of gated in control system.

How the normal operation of transistor is achieved?

Give any two characteristics of operational amplifier.

How does the motion of an electron in n type substance differ from the motion of holes in a p type substance?

What is OP-GATE?

How the current flows in forward and reverse biased diode?

Define Depletion region?

The anode of a diode is 0.2V positive with respect to the cathode,It it forward biased?

ICS Part 2 Physics Chapter 18 Short Questions Preparation

12th Class Physics
Short Questions Preparation