ICS Part 2 Physics Chapter 20 Short Questions Preparation

Question # 1

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 # 2

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 # 3

Explain why laser action could not occur without population inversion between atomic levels?

Ans 1: When a large percentage of atom or sample are in population inversion,then large number of coherent photons along same direction of motion could be obtained to form laser light,It is impossible withput population inversion.

Question # 4

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 # 5

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

Ans 1: The color of line spectrum of hydrogen atom are
- Red
- Blue
- Blue-Green
- Violet
- Ultraviolet

Question # 6

Define population inversion and metastable stable.

Ans 1: A condition of matter in which more electrons are in a high energy state than in a lower energy state is called population inversion.
A particular excited state of an atom that has longer lifetime than the ordinary excited states is called metastable state.

Question # 7

Can electron reside inside the nucleus?

Ans 1: No,electron cannot reside inside the nucleus .If electron resides inside nucleus then uncertainty in position.

Question # 8

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

Ans 1: Chararcterstics X-rays: The x-rays emitted from inner shell transitions are called characteristics x-rays and their energy depends on the type of target material.
Continuous X-rays:The x-rays emitted having continuous range of frequencies due to bremsstrahlung effect are called continuous x rays.

Question # 9

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 # 10

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.

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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

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.

Explain why laser action could not occur without population inversion between atomic levels?

What is meant by lasing action?

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

Define population inversion and metastable stable.

Can electron reside inside the nucleus?

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

Distinguished between stimulated emission and spontaneous emission.

What is CAT scanner?

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

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.

Explain why laser action could not occur without population inversion between atomic levels?

What is meant by lasing action?

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

Define population inversion and metastable stable.

Can electron reside inside the nucleus?

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

Distinguished between stimulated emission and spontaneous emission.

What is CAT scanner?

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

what is Spectroscopy?

Write use of x-rays.

Briefly describe 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?

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

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

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

Give two uses of laser in medicine and industry.

What is fluorescence?

What is CAT scanner?

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

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

Distinguished between stimulated emission and spontaneous emission.

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

Write use of x-rays.

What do you mean by inner shell transition?

Give two uses of laser in medicine and industry.

what is Spectroscopy?

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

What is CAT scanner?

Write two properties of x-rays.

ICS Part 2 Physics Chapter 20 Short Questions Preparation

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