ICS Part 2 Physics Chapter 18 Short Questions Preparation

Question # 1

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 # 2

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 # 3

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 # 4

What is semiconductor diode?

Ans 1: p-n junction is called semiconductor diode.

Question # 5

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 # 6

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 # 7

What is AND Gate?

Ans 1: It is a logic gate that implements the truth table of AND operations.It has two or more input and single output.

Question # 8

What is the net charge on a n-type or p-type substance?

Ans 1: Since they are electrically neutral substance,So the net charge on them is zero.

Question # 9

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 # 10

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.

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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

What is photodiode?Write down its two main applications.

Why the base current is transistor is very small?

Why charge carriers are not present in the depletion region?

What is semiconductor diode?

Differentiate between the forward biased and the reserve biase.

How is p-n junction formed?

What is AND Gate?

What is the net charge on a n-type or p-type substance?

Write a note on LED.

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

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

What is photodiode?Write down its two main applications.

Why the base current is transistor is very small?

Why charge carriers are not present in the depletion region?

What is semiconductor diode?

Differentiate between the forward biased and the reserve biase.

How is p-n junction formed?

What is AND Gate?

What is the net charge on a n-type or p-type substance?

Write a note on LED.

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

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

Differentiate between the forward biased and the reserve biase.

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

What is meant by rectification?

Give four application or uses of photodiode?

Explain why an ordinary Silicon diode does not emit light.

How is the XOR gate so called?

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

Write a note on LED.

Define Depletion region?

What is the net charge on a n-type or p-type substance?

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

What is semiconductor diode?

Define logic system and logic gates.

What is OP-GATE?

Why charge carriers are not present in the depletion region?

What is AND Gate?

Why is the photodiode operated in reverse biased state?

Give four application or uses of photodiode?

How the current flows in forward and reverse biased diode?

Define Depletion region?

What is meant by rectification?

ICS Part 2 Physics Chapter 18 Short Questions Preparation

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