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

Can x-rays be reflected,diffracted polarized just like any other eaves?Explain

Ans 1: Yes x rays can be reflected,refracted diffracted by crystal only and polarized just like any other waves.

Question # 3

What is meant by lasing action?

Ans 1: When a large percentage of atom or sample is in population inversion then large number of coherent photons along same direction of motion could be obtained to form laster light,The combination of spontaneous emission of first and then stimulated emission cause the laser to generate coherent beam of light at a single frequency which is called lasing action.

Question # 4

Write down use of laser in industry.

Ans 1: It can be used for telecommunication in fibre optics.
It is used to read bar codes,
It is used to generate 3D image of objects by holography.

Question # 5

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 # 6

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.

Question # 7

What is CAT scanner?

Ans 1: A vastly improved x-rays technique is computerized axial tomography: the corresponding instrument is called CAT scanner.In CAT scanning a number of different orientations.Computer is attached to construct picture,Density difference of the order of one percent can be detected,Tumors and other anomalies much too small to be seen with older techniques can be detected.

Question # 8

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

Ans 1: Bohr's first assumptions contradicts classical physics.Bohr said that electron do not radiate energy during revolving while according to classical physics,electron radiate energy during revolving and fall into the nucleus which is impossible.

Question # 9

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 # 10

What do you mean by inner shell transition?

Ans 1: A transition in which an electron from higher orbit,emits energy and accommodate a hole in the lower orbit.Such a transition is called inner shell transition.The photons emitted in such transition are called characteristic x-rays.

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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.

Can x-rays be reflected,diffracted polarized just like any other eaves?Explain

What is meant by lasing action?

Write down use of laser in industry.

What are the difference between laser light and ordinary light?

Define normal population and population inversion.

What is CAT scanner?

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

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

What do you mean by inner shell transition?

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.

Can x-rays be reflected,diffracted polarized just like any other eaves?Explain

What is meant by lasing action?

Write down use of laser in industry.

What are the difference between laser light and ordinary light?

Define normal population and population inversion.

What is CAT scanner?

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

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

What do you mean by inner shell transition?

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

Define normal population and population inversion.

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

How does a Kax-rays differ KbX-rays?

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

Differentiate between Line and Band spectrum.

Write down use of laser in industry.

What is CAT scanner?

What are the difference between laser light and ordinary light?

What is meant by lasing action?

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

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

Define continuous spectrum.

What is meant by lasing action?

Define normal population and population inversion.

What are the difference between laser light and ordinary light?

Write two properties of 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?

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

Distinguished between stimulated emission and spontaneous emission.

List of color of line spectra of an excited hydrogen atom.

What is fluorescence?

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?