Physics

Matter and Quantum Mechanics

1,427 Questions

This topic addresses core concepts in quantum mechanics, statistical thermodynamics, and states of matter. Questions cover quantum field theory, particle behavior, and statistical distributions. This material is essential for physics competitive exams.

Statistical ensemblesQuantum field theoryParticle physicsStates of matterWave particle duality

Matter and Quantum Mechanics Questions

Multiple choice physics dual nature of matter and radiation davisson and germer experiment and its conclusion matter waves wave nature of matter

Davisson and Germer studied the diffraction from crystal of beams of

  1. Alpha particles

  2. Protons

  3. Electrons

  4. Photons
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Davisson and Germer's actual objective was to study the surface of a piece of nickel by directing a beam of electrons at the surface and observing how many electrons bounced off at various angles. They expected that because of the small size of electrons, even the smoothest crystal surface would be too rough and thus the electron beam would experience diffuse reflection.

During the experiment an accident occurred and air entered the chamber, producing an oxide film on the nickel surface. To remove the oxide, Davisson and Germer heated the specimen in a high temperature oven, not knowing that this affected the formerly polycrystalline structure of the nickel to form large single crystal areas with crystal planes continuous over the width of the electron beam. 

When they started the experiment again and the electrons hit the surface, they were scattered by atoms which originated from crystal planes inside the nickel crystal.In 1925, they generated a diffraction pattern with unexpected peaks.

So, the answer is option (C).

Multiple choice relativistic mechanics option a: relativity physics

Statement saying that energy is radiated or absorbed in discrete packets is given by ____________.

  1. Planck

  2. Einstein

  3. Stephen

  4. Wien
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
According to Planck’s quantum theory, Different atoms and molecules can emit or absorb energy in discreet quantities only. 
Multiple choice relativistic mechanics option a: relativity physics

Quantum effects are important only when observing _____________.

  1. small objects

  2. very large objects

  3. atomic size objects

  4. all of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Quantum theory is the theoretical basis of modern physics that explains the nature and behaviour of matter and energy on the atomic and subatomic level. So quantum effect is important only when observing atomic size objects.
Multiple choice relativistic mechanics option a: relativity physics

Behavior of matter on atomic level cannot be explained with ____________.

  1. modern physics

  2. classical physics

  3. relativistic mechanics

  4. atomic spectra
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
As Classical physics is the study of motion, projectiles, pulleys, and the planets. It mainly deals with the movement of large objects through space at a relatively low slow speed. 
Multiple choice chemistry atoms, molecules and radicals history of atomic model atomic theory of dalton daltons atomic theory

Various theories were put forth to study the nature of atom. The main postulates of Dalton's atomic theory are :

  1. all matter are composed of atoms

  2. all matters are composed of molecules

  3. all atoms of an element are identical.

  4. the atoms of different elements vary in size and mass.
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Explanation

It was John Dalton who firstly developed a theory on the structure of matter, later on which is known as Dalton's atomic theory.


DALTON'S ATOMIC THEORY :

1. Matter is made up of very small undivisible particle called atoms.
2. All the atoms of a given element is identical in all respect i.e. mass, shape, size, etc.
3. Atoms cannot be created nor destroyed by any chemical process.
4. Atoms of different elements are different in nature.

Multiple choice chemistry atoms, molecules and radicals history of atomic model atomic theory of dalton daltons atomic theory

Which of the following is a merit of Dalton's atomic theory?

  1. Laws of chemical combination

  2. Distinction between the fundamental particle of an element (atom) and that of a compound (molecule)

  3. Both A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 Dalton's theory explains the laws of chemical combination.  Dalton was the first person to recognize a workable difference between the fundamental particle of an element (atom) and that of a compound (molecule).

Multiple choice chemistry atoms, molecules and radicals history of atomic model atomic theory of dalton daltons atomic theory

Which one proposes the basic postulates concerning elements and atoms?

  1. Avogadro's number
  2. $P _1V _1=P _2V _2$
  3. $V _1T _2=V _2T _1$

  4. Dalton's theory

  5. Gay-Lussac's Law
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Dalton's theory proposes the basic postulates concerning elements and atoms.


All matter is made of atoms. Atoms are indivisible and indestructible. 

All atoms of a given element are identical in mass and properties.  

  Hence, the correct option is D.

Multiple choice chemistry atoms, molecules and radicals history of atomic model atomic theory of dalton daltons atomic theory

An important postulate of Dalton's atomic theory is: 

  1. an atom contains electrons, protons and neutrons

  2. atom can neither be created nor destroyed nor divisible

  3. all the atoms of an element are not identical

  4. all the elements are available in nature in the form of atoms
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to Dalton's theory, atoms can neither be created nor be destroyed.

Multiple choice physics bharat and science scope and progress of physics recent advancement in medical technology contribution of physics in technology and society

Which of the following statements is not correct. ?

  1. Physics is the study of nature and natural phenomena.

  2. Physics and technology are not related to each other.

  3. Electrodynamics deals with electric and magnetic phenomena associated with charged and magnetic bodies.

  4. The physical quantities that remain unchanged in a process are called conserved quantities.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Complex technologies are making use of more rarefied physical concepts. Physics describes the things that are possible in the universe, and technology is eventually built to do work within that which has been discovered by physics. This interplay also works in reverse. Modern physicists are frequently making use of extremely high-tech machines and processes. For example, the Large Hadron Collider in Switzerland is the world's largest particle accelerator. It can be operated at higher energies than any previous one. It was built explicitly to perform experiments in particle physics.

Thus Physics and technology are very much related to each other. So statement B is not appropriate. Although the other three statements are very much correct and factful.

Thus option B is correct.

Multiple choice physics bharat and science scope and progress of physics recent advancement in medical technology contribution of physics in technology and society

What is the two principal thrust in Physics?

  1. Unification and Reduction

  2. Unification and Oxidation

  3. Magnification and Reduction

  4. Simplification and Reduction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The principal thrust in physics is to unity all the fundamental forces into a single framework and reduce the no.of different theories to minimal no. of models which can describe a great number of a phenomenon. (a)

where Unification is the act of unifying the different laws valid for different phenomena into a single theory that explains all the different phenomena.

The reduction is breaking down of a complex system into simple constituent systems to so that laws of physics can be applied to these systems and we can understand the working of the complex system.

Multiple choice physics bharat and science scope and progress of physics recent advancement in medical technology contribution of physics in technology and society

Which of the following phenomena does not come under macroscopic domain?

  1. Phenomena at laboratory scales

  2. Phenomena at terrestrial scales

  3. Molecular and nuclear phenomena

  4. Phenomena at astronomical scales
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Molecular and nuclear phenomenon come under microscopic domain.

Multiple choice physics bharat and science scope and progress of physics recent advancement in medical technology contribution of physics in technology and society

Physics is sometimes referred to as exact science. Because.

  1. Physics interacts with almost all the sciences

  2. Due important is given for the measurement of quantities

  3. It involves philosophy

  4. Physics is related more closely to mathematics than any other science
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

More importance is given to measurement of quantities, i.e., qualitative analysis. 

Multiple choice physics bharat and science scope and progress of physics recent advancement in medical technology contribution of physics in technology and society

Werner Heisenberg is known for his work on 

  1. Inelastic scattering of light by molecules

  2. Quantum mechanics: Uncertainty principle

  3. Theory of super conductivity

  4. Expanding universe
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B

In quantum mechanics, the uncertainty principle, also known as Heisenberg's uncertainty principle, is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables, such as position and momentum, cannot be known simultaneously.