ICS Part 2 Physics Chapter 20 Short Questions Preparation

Question # 1

Distinguished between stimulated emission and spontaneous emission.

Ans 1: Stimulated emission: If a atom is excited for a longer lifetime of about 10^-3sec than an incident photon of energy equal to the difference of two energy levels induces the atom to decay by emitting a photon that travel in the direction of incident photon.This process is called stimulated or induced emission.
Ans 2: Spontaneous Emission: As excited is highly unstable with life time of
10^-8sec,so electron will de excite itself with emission of a photon in any arbitrarydirection is called spontaneous emission.

Question # 2

How does a K_ax-rays differ K_bX-rays?

Ans 1: When an electron from L -shell jumps to occupy the hole in K- shell K_ax-rays is emitted .
And
When an electron from M -shells jumps to occupy the hole in K-Shell K_bX-rays is emited.

Question # 3

Write two postulate of Bohr's model of H-atom.

Ans 1:
- An electron ,bound to the nucleus in an atom,can moved around the nucleus in certain circular orbits without radiating,These orbits are called the discrete stationary orbits.
- Only those stationary orbits are allowed for which orbital angular momentum is equal to an integral multiple mvr=nh/2π.

Question # 4

In which region of electromagnetic spectrum does the following series fall (a)Lyman series (b)Balmer series?

Ans 1: Balmer series falls in the visible region.
Lyman series falls in the ultraviolet region.

Question # 5

What is meant by line spectrum? How line spectrum can be used for the identification of elements?

Ans 1: When an electron jumps from higher energy state to lower energy state than emits energy and make a spectral line.
E₂- E₁_=hf
_{This is called line spectrum.And different elements emit line spectrum of different wavelengths,So they can be identifiedeasily.}

Question # 6

What are the advantages of laser over ordinary light?

Ans 1: Laser light has many advantages over ordinary light such as laser light is
1. Coherent
2. Intense
3. Monochromatic
4. Unidirectional

Question # 7

Is energy conserved when an atom emits a photon of light?

Ans 1: Yes energy is conserved when an excited atom emits a photon of light.When atom is excited ,energy is supplied .The same energy is emitted in the form of photon when it return back to its ground state.

Question # 8

Give two uses of laser in medicine and industry.

Ans 1: Laser is used
1. For welding detached retinas
2. To destroy cancerous and precancerous cells.

Question # 9

What are the difference between laser light and ordinary light?

Ans 1: The laser light is intense ,unidirectional and phase coherent ,so it does bit spread as compared to ordinary light.
The energy of laser can be focused at a point to get enough heat for welding which is not possible with ordinary light.
A laser beam is used as a surgical tool for welding detached retina which ordinary light can not do.

Question # 10

Define normal population and population inversion.

Ans 1: In normal population ,the lower energy state has a greater population than the higher energy state.
Population inversion occurs when no more electron are in a higher energy state than in lower energy state.

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ICS Part 2 Physics Chapter 20 Short Questions Preparation

12th Class PhysicsShort Questions Preparation

12th Class Physics Chapter Wise Preparation

Online Short Questions For Chapter 9 "ICS Part 2 Physics Chapter 20 Short Questions Preparation "

Physics - ICS Part 2 Physics Chapter 20 Short Questions Preparation

Distinguished between stimulated emission and spontaneous emission.

How does a Kax-rays differ KbX-rays?

Write two postulate of Bohr's model of H-atom.

In which region of electromagnetic spectrum does the following series fall (a)Lyman series (b)Balmer series?

What is meant by line spectrum? How line spectrum can be used for the identification of elements?

What are the advantages of laser over ordinary light?

Is energy conserved when an atom emits a photon of light?

Give two uses of laser in medicine and industry.

What are the difference between laser light and ordinary light?

Define normal population and population inversion.

Prepare Complete Set Wise Questions For Chapter 9 "ICS Part 2 Physics Chapter 20 Short Questions Preparation "

Set 1

Set 2

Set 3

ICS Part 2 Physics Chapter 20 Short Questions Preparation - Set 1

Distinguished between stimulated emission and spontaneous emission.

How does a Kax-rays differ KbX-rays?

Write two postulate of Bohr's model of H-atom.

In which region of electromagnetic spectrum does the following series fall (a)Lyman series (b)Balmer series?

What is meant by line spectrum? How line spectrum can be used for the identification of elements?

What are the advantages of laser over ordinary light?

Is energy conserved when an atom emits a photon of light?

Give two uses of laser in medicine and industry.

What are the difference between laser light and ordinary light?

Define normal population and population inversion.

ICS Part 2 Physics Chapter 20 Short Questions Preparation - Set 2

Distinguished between stimulated emission and spontaneous emission.

What do we mean when we say that the atom is excited?

How can spectrum of hydrogen contain so many lines,whereas hydrogen atom contain one electron?

What are the advantages of laser over ordinary light?

Define population inversion and metastable stable.

What is meant by line spectrum? How line spectrum can be used for the identification of elements?

What is fluorescence?

Bohr's theory of hydrogen atom is based upon several assumptions.Do any of these assumptions contradict classical physics?

Define characteristics of X-rays and continuous x-rays.

Can the electron in the ground state of hydrogen atom absorb a photon of energy 13.6 eV greater than 13.6 eV?

ICS Part 2 Physics Chapter 20 Short Questions Preparation - Set 3

What is meant by lasing action?

Can the electron in the ground state of hydrogen atom absorb a photon of energy 13.6 eV greater than 13.6 eV?

What do you mean by inner shell transition?

Is energy conserved when an atom emits a photon of light?

Write two postulate of Bohr's model of H-atom.

Write two properties of x-rays.

In which region of electromagnetic spectrum does the following series fall (a)Lyman series (b)Balmer series?

How can spectrum of hydrogen contain so many lines,whereas hydrogen atom contain one electron?

What is CAT scanner?

Write use of x-rays.

ICS Part 2 Physics Chapter 20 Short Questions Preparation

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12th Class Physics
Short Questions Preparation

How does a K_ax-rays differ K_bX-rays?

How does a K_ax-rays differ K_bX-rays?