Case Study Questions Class 11 Physics Chapter 1 Physical World
CBSE Class 11 Case Study Questions Physics Physical World. Important Case Study Questions for Class 11 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Physical World.
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CBSE Case Study Questions Class 11 Physics Physical World
1.) Fundamental forces in nature are enlisted below
Gravitational force:The gravitational force is the force of mutualattraction between any two objects by virtue oftheir masses. It is a universal force. Every objectexperiences this force due to every other objectin the universe. All objects on the earth for example, experience the force of gravity due to the earth.
Electromagnetic force:Electromagnetic force is the force between charged particles. In the simpler case whencharges are at rest, the force is given byCoulomb’s law : attractive for unlike charges andrepulsive for like charges. Charges in motionproduce magnetic effects and a magnetic fieldgives rise to a force on a moving charge. Electricand magnetic effects are, in general,inseparable – hence the name electromagneticforce. Like the gravitational force,
Electromagnetic force acts over large distancesand does not need any intervening medium. It
is enormously strong compared to gravity. Theelectric force between two protons, for example,
is 1036 times the gravitational force betweenthem, for any fixed distance.
Strong nuclear force:The strong nuclear force is the strongest of all fundamental forces, about 100 times the electromagnetic force instrength. It is charge-independent and actsequally between a proton and a proton, aneutron and a neutron, and a proton and aneutron. Its range is, however, extremely small,of about nuclear dimensions (10–15m). It isresponsible for the stability of nuclei. Theelectron, it must be noted, does not experiencethis force.
Weak nuclear forces:The weak nuclear force appears only in certainnuclear processes such as the b-decay of anucleus. In b-decay, the nucleus emits anelectron and an uncharged particle calledneutrino. The weak nuclear force is not as weakas the gravitational force, but much weakerthan the strong nuclear and electromagneticforces. The range of weak nuclear force is
Exceedingly small, of the order of 10-16 m. answer the following
1.) Weakest force in nature is
(a) Gravitational force
(b) Electromagnetic force
(c) Strong nuclear force
(d) None of these
2.) Strongest fundamental force in nature
(a) Gravitational force
(b) Electromagnetic force
(c) Strong nuclear force
(d) None of these
3.) Write short note on electromagnetic force in nature.
4.) Write short note on gravitational force in nature.
5.) Differentiate between gravitational force and electromagnetic force in nature.
Answer key-1
(1) a
(2) b
(3) Electromagnetic force: The force between charged particles is called electromagnetic force.Electricand magnetic effects are always occurs simultaneously as they are cause for production of each other hence the name electromagneticforce. Electromagnetic force acts over large distances and does not need anymedium. Itisstrong compared to gravitational forces but weak compared to strong Nuclear force.
(4) Gravitational force:The gravitational force is the attraction force between all the bodies having masses.It is a universal force hence called universal force. It plays a important role in phenomena like formation and evolution of stars, galaxies etc.
(5) Following is the difference
Sr No.
|
Gravitational force | Electromagnetic force |
it is the force that acts on an object due to gravity | It is the force that acts on charged particles | |
It acts on any object that has mass | It acts on either charged particles or iron containing particles | |
Weak force as compare to electromagnetic force | Strong force as compare to gravitational force |
Case 2
2.) Fundamental forces in nature are enlisted below
Gravitational force:The gravitational force is the force of mutualattraction between any two objects by virtue oftheir masses. It is a universal force. Every objectexperiences this force due to every other objectin the universe. All objects on the earth for example, experience the force of gravity due to the earth.
Electromagnetic force:Electromagnetic force is the force between charged particles. In the simpler case whencharges are at rest, the force is given byCoulomb’s law : attractive for unlike charges andrepulsive for like charges. Charges in motionproduce magnetic effects and a magnetic fieldgives rise to a force on a moving charge. Electricand magnetic effects are, in general,inseparable – hence the name electromagneticforce. Like the gravitational force,
Electromagnetic force acts over large distancesand does not need any intervening medium. It
is enormously strong compared to gravity. Theelectric force between two protons, for example,
is 1036 times the gravitational force betweenthem, for any fixed distance.
Strong nuclear force:The strong nuclear force is the strongest of all fundamental forces, about 100 times the electromagnetic force instrength. It is charge-independent and actsequally between a proton and a proton, aneutron and a neutron, and a proton and aneutron. Its range is, however, extremely small,of about nuclear dimensions (10–15m). It isresponsible for the stability of nuclei. Theelectron, it must be noted, does not experiencethis force.
Weak nuclear forces:The weak nuclear force appears only in certainnuclear processes such as the b-decay of anucleus. In β-decay, the nucleus emits anelectron and an uncharged particle calledneutrino. The weak nuclear force is not as weakas the gravitational force, but much weakerthan the strong nuclear and electromagneticforces. The range of weak nuclear force is
Exceedingly small, of the order of 10-16 m. answer the following.
1.) The force needed for stability of nuclei is
(a) Electromagnetic force
(b) Strong nuclear force
(c) Weak nuclear force
(d) None of these
2.) The force needed for radioactive decay is
(a) Electromagnetic force
(b) Strong nuclear force
(c) Weak nuclear force
(d) None of these
3.) Write short note on strong nuclear force in nature.
4.) Write short note on weak nuclear force in nature.
5.) Differentiate between strong nuclear force and weak nuclear force.
Answer key-2
(1) b
(2) c
(3) The strong nuclear force is the strongest force exist in nature.this force is same for proton proton and proton nuetron pair hence we can say that it does not depend on charges. even though it is strongest force but its range is very small of the order of (10-15m). in atom nuclei is stable as a result of this force.
(4) The weak nuclear force observed only in fewphenomenon such as the beta-decay of a nucleus. The weak nuclear force is stronger than gravitational force, but weaker than the strong nuclear and electromagnetic forces. The range of weak nuclear force isvery small, of the order of 10-16 m.
(5) differentiation between strong nuclear force and weak nuclear force is as follows
Sr No. | Strong nuclear force | weak nuclear force |
This force responsible for stability of nuclei. | The force responsible for radioactive decay | |
Range is 10-15m | Range is of the order of 10-16m | |
Played major role in holding nuclei together | Played major role in nuclear reactions and radioactive decay | |
Stronger force than weak nuclear force | Weaker than strong nuclear force |
Case 3
3.) The word Science originates from the Latin verb Scientia meaning ‘to know’. What is Science and what is the so-called Scientific Method? Science is a systematic attempt to understand natural phenomena in as much detail and depth as possible, and use the knowledge so gained to predict, modify andcontrol phenomena. Science is exploring, experimenting and predicting from what we see around us. The curiosity to learn about the world, unraveling the secrets of nature is the first step towards the discovery of science. The scientific method involves several interconnected steps: Systematic observations, controlled experiments, qualitative and quantitative reasoning, mathematical modeling, prediction and verification or falsification of theories. Speculation and conjecture also have a place in science; butultimately, a scientific theory, to be acceptable, must be verified by relevant observations orexperiments.The interplay of theory and observation (orexperiment) is basic to the progress of science.Science is ever dynamic. There is no ‘final’theory in science and no unquestioned authority among scientists. Physics is a basic discipline in the categoryof Natural Sciences, which also includes otherdisciplines like Chemistry and Biology.We can get some idea of the scope of physics bylooking at its various sub-disciplines. Basically,there are two domains of interest: macroscopicand microscopic. The macroscopic domainincludes phenomena at the laboratory, terrestrialand astronomical scales. The microscopic domainincludes atomic, molecular and nuclearphenomena. Classical Physics deals mainly with macroscopic phenomena and includes subjects like Mechanics, Electrodynamics,Optics and Thermodynamics.The microscopic domain of physics deals withthe constitution and structure of matter at theminute scales of atoms and nuclei (and evenlower scales of length) and their interaction withdifferent probes such as electrons, photons and other elementary particles.
(1) The meaning of Latin word Scientia
(a) To know
(b) To tackle
(c) To hear
(d) None of these
(2) Physics chemistry and biology are
(a) Natural sciences
(b) Applied sciences
(c) Both a and b
(d) None of these
(3) Which of the following represents discipline of natural sciences?
(a) Physics
(b) Chemistry
(c) Biology
(d) All of these
(4) What is science?
(5) Differentiate between microscopic and macroscopic domain
Answer key-3
(1) a
(2) a
(3) d
(4) Science is a systematic attempt to understand natural phenomena in such detail and depthand use the knowledge achieved to predict, modify andcontrol phenomena.
(5) Following are difference between microscopic and macroscopic domain
Sr No. | Microscopic domain | macroscopic domain |
It deals withthe constitution and structure of matter at the atomic level | It includes phenomena at the laboratory, terrestrialand astronomical scales | |
Analysis gives idea about behavior of constituent particle | Analysis gives idea about behavior of system | |
Quantum physics deals mainly with microscopic phenomena. | Classical Physics deals mainly with macroscopic phenomena. |
Case 4
4.) In any physical phenomenon governed bydifferent forces, several quantities may changewith time. A remarkable fact is that some specialphysical quantities, however, remain constantin time. They are the conserved quantities ofnature. Understanding these conservationprinciples is very important to describe theobserved phenomena quantitatively. For motion under an external conservativeforce, the total mechanical energy i.e. the sumof kinetic and potential energy of a body is aconstant. The familiar example is the free fall ofan object under gravity. Both the kinetic energyof the object and its potential energy changecontinuously with time, but the sum remains fixed.
According to Einstein’s theory, mass m isequivalent to energy E given by the relationE = mc2, where c is speed of light in vacuum.Energy is a scalar quantity. But all conservedquantities are not necessarily scalars. The totallinear momentum and the total angular momentum (both vectors) of an isolated systemare also conserved quantities. These laws can be derived from Newton’s laws of motion inmechanics. But their validity goes beyond mechanics. They are the basic conservationlaws of nature in all domains, even in thosewhere Newton’s laws may not be valid.Physics deals with the study of the basic laws of nature and their manifestation indifferent phenomena. The basic laws of physics are universal and apply in widely differentcontexts and conditions.The scope of physics is wide, covering a tremendous range of magnitude of physicalquantities. Physics and technology are related to each other. Sometimes technology gives rise tonew physics; at other times physics generates new technology. Both have direct impacton society.
(1) mass m is equivalent to energy E given by
(a) Newton’s law of gravitation
(b) Einstein’s theory.
(3) Galileo theory.
(4) None of these
(2) Energy is
(a) Scalar
(b) Vector
(c) Tensor
(d) None of these
(3) What is mass energy relation?
(4) What do you mean by conserved quantities of nature?
(5) What is physics?
Answer key-4
(1) b
(2) a
(3) According to Einstein’s theory, mass m is equivalent to energy E given by the relation
E = mc2, where c is speed of light in vacuum.
(4) quantities which are remain constant with respect to time are called as conserved or constant quantities of nature.
(5) Physics is the study of the basic laws of nature and their application indifferent phenomena. The basic laws of physics are universal and applicable to everywhere in nature