Rclipse - Education Point: PHYSICS

Showing posts with label PHYSICS. Show all posts
Showing posts with label PHYSICS. Show all posts

कृष्णिका विकिरण (Black Body Rediation) || Black Body Rediation In Hindi || Krishnika Vikiran In Hindi || Krashnika Vikiran

कृष्णिका विकिरण
(Black Body Rediation)

कृष्णिका ऐसे पिण्ड के रूप में परिभाषित की जा सकती है जो स्वयं पर आपतित सभी आवृतियों (तरंगदैध्र्यों) के विकिरणों को पूर्णतया अवशोषित कर लेती है। कृष्णिका के प्रतिरूप के लिये कोटर पर विचार करते है जिसकी दीवारें एक निश्चित ताप पर है तथा भीतरी दीवारें काली की हुई होती है। कोटर की दीवार के परमाणु विद्युत चुम्बकीय विकिरण उत्सर्जित करते है, जो कोटर के भीतर की दिवारों से परावर्तित एवं अवशोषित हो सकते है। कोटर के भीतर का सम्पूर्ण भाग विद्युत चुम्बकीय विकिरणों से भर जाता है तथा साम्यावस्था में होता है। अर्थात परमाणुओं द्वारा प्रति सैकण्ड उत्सर्जित उर्जा का मान, उनके द्वारा प्रति सैकण्ड अवशोषित उर्जा के मान के बराबर होता है। उष्मीय साम्यावस्था में कोटर के भीतर विकिरणों का उर्जा घनत्व नियत रहता है। कोटर की दीवार में बने एक छिद्र से विकिरण बाहर उत्सर्जित होता रहता है। कोटर के छिद्र से बाहर निकलने वाले विकिरण को कृष्णिका विकिरण (Black Body Radiation) कहते है।

कृष्णिका के लिये उत्सर्जन क्षमता (Eλ) तथा तरंगदैध्र्य (λके मध्य ग्राफ :

कृष्णिका विकिरणों का विश्लेषण सर्वप्रथम, लूमर (Lummer) तथा प्रिंगशाइम (Pringsheim) द्वारा 1899 में किया गया था। स्तर तथा प्रिंगशाइम ने विभिन्न तापों पर कृष्णिका की स्पेक्टमी उत्सर्जन क्षमता  (Eλ) तथा तरंगदैध्र्य (λ) का मापन किया। कृष्णिका के लिये उत्सर्जन क्षमता (Eλ) तथा तरंगदैध्र्य (λ) के मध्य ग्राफ को स्पेक्टमी उर्जा वितरण ग्राफ कहते है।

Coulomb's Law Physics || Law Of Coulomb's || Ncert Solution Of Physics || Physics Ncert Solution || Defense Exams Notes In Pdf

Coulomb’s law is a quantitative statement about the force between two point charges. When the linear size of charged bodies are much smaller than the distance separating them, the size may be ignored and the charged bodies are treated as point charges. Coulomb measured the force between two point charges and found that it varied inversely as the square of the distance between the charges and was directly proportional to the product of the magnitude of the two charges and acted along the line joining the two charges. Thus, if two point charges q1, q2 are separated by a distance r in vacuum, the magnitude of the force (F) between them is given by

F = k


r 2

How did Coulomb arrive at this law from his experiments? Coulomb used a torsion balance* for measuring the force between two charged metallic spheres. When the separation between two spheres is much larger than the radius of each sphere, the charged spheres may be regarded as point charges. However, the charges on the spheres were unknown, to begin with. How then could he discover a relation like Eq. (1.1)? Coulomb thought of the following simple way: Suppose the charge on a metallic sphere is q. If the sphere is put in contact with an identical uncharged sphere, the charge will spread over the two spheres. By symmetry, the charge on each sphere will be q/2*. Repeating this process, we can get charges q/2, q/4, etc. Coulomb varied the distance for a fixed pair of charges and measured the force for different separations. He then varied the charges in pairs, keeping the distance fixed for each pair. Comparing forces for Charles Augustin de different pairs of charges at different distances, Coulomb arrived at the relation, Eq. (1.1).

Coulomb’s law, a simple mathematical statement, was initially experimentally arrived at in the manner described above. While the original experiments established it at a macroscopic scale, it has also been established down to subatomic level

(r ~ 10–10 m).

Coulomb discovered his law without knowing the explicit magnitude of the charge. In fact, it is the other way round: Coulomb’s law can now be employed to furnish a definition for a unit of charge. In the relation, Eq. (1.1), k is so far arbitrary. We can choose any positive value of k. The choice of k determines the size of the unit of charge. In SI units, the value of k is about 9 × 109. The unit of charge that results from this choice is called a coulomb which we defined earlier in Section 1.4. Putting this value of k in Eq. (1.1), we see that for Coulomb discovered his law without knowing the explicit magnitude of the charge. In fact, it is the other way round: Coulomb’s law can now be employed to furnish a definition for a unit of charge. In the relation, Eq. (1.1), k is so far arbitrary.

We can choose any positive value of k. The choice of k determines the size of the unit of charge. In SI units, the value of k is about 9 × 109. The unit of charge that results from this choice is called a coulomb which we defined earlier in Section 1.4. Putting this value of k in Eq. (1.1), we see that for 

q1 = q2 = 1 C, r = 1 m F = 9 × 109 N

That is, 1 C is the charge that when placed at a distance of 1 m from another charge of the same magnitude in vacuum experiences an electrical force of repulsion of magnitude 9 × 109 N.

One coulomb is evidently too big a unit to be used. In practice, in electrostatics, one uses smaller units like 1 mC or 1 µC.

The constant k  in Eq. (1.1) is usually put as
k = 1/4πε0 for later convenience, so that Coulomb’s law is written as


q  q

F =


4 π ε0

r 2

ε0 is called the permittivity of free space . The value of ε0 in SI units is 

ε 0 = 8.854 × 10–12 C2 N–1m–2

Since force is a vector, it is better to write Coulomb’s law in the vector notation. Let the position vectors of charges q1 and q2 be r1 and r2 respectively [see Fig.1.6(a)]. We denote force on
q1  due to q2  by F12  and force on q2 due to q1 by
F21. The two point charges q1  and q2 have been

numbered 1 and 2 for convenience and the vector

leading from 1 to 2 is denoted by r21:r21 = r2 – r1

In the same way, the vector leading from 2 to 
1 is denoted by

r12 = r1 – r2 = – r21

The magnitude of the vectors r21  and r12  is 
denoted by r21 and r12 , respectively (r12 = r21). The 
direction of a vector is specified by a unit vector 
along the vector. To denote the direction from 1 
to 2 (or from 2 to 1), we define the unit vectors:



r 21  =

r 12  =

r 21  =
r 12

Coulomb’s force law between two point charges q1 and q2 located at r1 and r2 is then expressed as


4 π ε

r 2
r 21



Some remarks on Eq. (1.3) are relevant:

Equation (1.3) is valid for any sign of q1 and q2 whether positive or negative. If q1 and q2 are of the same sign (either both positive or both negative), F21 is along rˆ 21, which denotes repulsion, as it should be for like charges. If q1 and q2 are of opposite signs, F21 is along – r 21(= r 12), which denotes attraction, as expected for unlike charges. Thus, we do not have to write separate equations for the cases of like and unlike charges. Equation (1.3) takes care of both cases correctly [Fig. 1.6(b)].

The force F12 on charge q1 due to charge q2, is obtained from Eq. (1.3), by simply interchanging 1 and 2, i.e.,



4 π ε

r 2
= −F21


Thus, Coulomb’s law agrees with the Newton’s third law.

Coulomb’s law [Eq. (1.3)] gives the force between two charges q1 and q2 in vacuum. If the charges are placed in matter or the intervening space has matter, the situation gets complicated due to the presence of charged constituents of matter. We shall consider electrostatics in matter in the next chapter.

Basic Properties Of Electric Charge Physics || Physics Ncert Solution In Pdf || Ncert Solution Complete || Class 12Ncert Physics

Basic Properties Of Electric Charge :

We have seen that there are two types of charges, namely positive and negative and their effects tend to cancel each other. Here, we shall now describe some other properties of the electric charge.

If the sizes of charged bodies are very small as compared to the distances between them, we treat them as point charges. All the charge content of the body is assumed to be concentrated at one point in space.

Additivity of charges :

We have not as yet given a quantitative definition of a charge; we shall follow it up in the next section. We shall tentatively assume that this can be done and proceed. If a system contains two point charges q1 and q2, the total charge of the system is obtained simply by adding algebraically q1 and q2 , i.e., charges add up like real numbers or they are scalars like the mass of a body. If a system contains n charges q1, q2, q3, …, qn, then the total charge of the system is q1 + q2 + q3 + … + qn . Charge has magnitude but no direction, similar to the mass. However, there is one difference between mass and charge. Mass of a body is always positive whereas a charge can be either positive or negative. Proper signs have to be used while adding the charges in a system. For example, the total charge of a system containing five charges +1, +2, –3, +4 and –5, in some arbitrary unit, is (+1) + (+2) + (–3) + (+4) + (–5) = –1 in the same unit.

Charge is conserved :

We have already hinted to the fact that when bodies are charged by rubbing, there is transfer of electrons from one body to the other; no new charges are either created or destroyed. A picture of particles of electric charge enables us to understand the idea of conservation of charge. When we rub two bodies, what one body gains in charge the other body loses. Within an isolated system consisting of many charged bodies, due to interactions among the bodies, charges may get redistributed but it is found that the total charge of the isolated system is always conserved. Conservation of charge has been established experimentally.

It is not possible to create or destroy net charge carried by any isolated system although the charge carrying particles may be created or destroyed in a process. Sometimes nature creates charged particles: a neutron turns into a proton and an electron. The proton and electron thus created have equal and opposite charges and the total charge is zero before and after the creation.

Quantisation of charge :

Experimentally it is established that all free charges are integral multiples of a basic unit of charge denoted by e. Thus charge q on a body is always given by

q = ne

where n is any integer, positive or negative. This basic unit of charge is the charge that an electron or proton carries. By convention, the charge on an electron is taken to be negative; therefore charge on an electron is written as –e and that on a proton as +e.

The fact that electric charge is always an integral multiple of e is termed as quantisation of charge. There are a large number of situations in physics where certain physical quantities are quantised. The quantisation of charge was first suggested by the experimental laws of electrolysis discovered by English experimentalist Faraday. It was experimentally demonstrated by Millikan in 1912.

In the International System (SI) of Units, a unit of charge is called a coulomb and is denoted by the symbol C. A coulomb is defined in terms the unit of the electric current which you are going to learn in a subsequent chapter. In terms of this definition, one coulomb is the charge flowing through a wire in 1 s if the current is 1 A (ampere). In this system, the value of the basic unit of charge is

e = 1.602192 × 10–19 C

Thus, there are about 6 × 1018 electrons in a charge of  –1C. In

electrostatics, charges of this large magnitude are seldom encountered and hence we use smaller units 

1 C (micro coulomb) = 10–6 C or 1 mC

(milli coulomb) = 10–3 C.

If the protons and electrons are the only basic charges in the universe, all the observable charges have to be integral multiples of e. Thus, if a body contains n1 electrons and n 2 protons, the total amount of charge on the body is n 2 × e + n1 × (–e) = (n 2 – n1) e. Since n1 and n2 are integers, their difference is also an integer. Thus the charge on any body is always an integral multiple of e and can be increased or decreased also in steps of e.

The step size e is, however, very small because at the macroscopic level, we deal with charges of a few C. At this scale the fact that charge of a body can increase or decrease in units of e is not visible. The grainy nature of the charge is lost and it appears to be continuous.

This situation can be compared with the geometrical concepts of points and lines. A dotted line viewed from a distance appears continuous to us but is not continuous in reality. As many points very close to each other normally give an impression of a continuous line, many small charges taken together appear as a continuous charge distribution.

At the macroscopic level, one deals with charges that are enormous compared to the magnitude of charge e.

Since e = 1.6 × 10–19 C, a charge of magnitude, say 1 C, contains something like 1013 times the electronic charge. At this scale, the fact that charge can increase or decrease only in units of e is not very different from saying that charge can take continuous values.

Thus, at the macroscopic level, the quantisation of charge has no practical consequence and can be ignored. At the microscopic level, where the charges involved are of the order of a few tens or hundreds of e, i.e., they can be counted, they appear in discrete lumps and quantisation of charge cannot be ignored. It is the scale involved that is very important.

Charging By Induction Physics || Class 12th Ncert || Complete Ncert Solution || Defence Recruitment || Defence Exams Update

Charging By Induction :

When we touch a pith ball with an electrified plastic rod, some of the negative charges on the rod are transferred to the pith ball and it also gets charged. Thus the pith ball is charged by contact. It is then repelled by the plastic rod but is attracted by a glass rod which is oppositely charged. However, why a electrified rod attracts light objects, is a question we have still left unanswered. Let us try to understand what could be happening by performing the following experiment.

(i) Bring two metal spheres, A and B, supported on insulating stands, in contact as shown in Fig. 1.4(a).

(ii) Bring a positively charged rod near one of the spheres, say A, taking care that it does not touch the sphere. The free electrons in the spheres are attracted towards the rod. This leaves an excess of positive charge on the rear surface of sphere B. Both kinds of charges are bound in the metal spheres and cannot escape. They, therefore, reside on the surfaces, as shown in Fig. 1.4(b). The left surface of sphere A, has an excess of negative charge and the right surface of sphere B, has an excess of positive charge. However, not all of the electrons in the spheres have accumulated on the left surface of A. As the negative charge starts building up at the left surface of A, other electrons are repelled by these. In a short time, equilibrium is reached under the action of force of attraction of the rod and the force of repulsion due to the accumulated charges. Fig. 1.4(b) shows the equilibrium situation. The process is called induction of charge and happens almost instantly. The accumulated charges remain on the surface, as shown, till the glass rod is held near the sphere. If the rod is removed, the charges are not acted by any outside force and they redistribute to their original neutral state.

(iii) Separate the spheres by a small distance while the glass rod is still held near sphere A, as shown in Fig. 1.4(c). The two spheres are found to be oppositely charged and attract each other.

(iv) Remove the rod. The charges on spheres rearrange themselves as shown in Fig. 1.4(d). Now, separate the spheres quite apart. The charges on them get uniformly distributed over them, as shown in Fig. 1.4(e).

In this process, the metal spheres will each be equal and oppositely charged. This is charging by induction. The positively charged glass rod does not lose any of its charge, contrary to the process of charging by contact.

When electrified rods are brought near light objects, a similar effect takes place. The rods induce opposite charges on the near surfaces of the objects and similar charges move to the farther side of the object.

[This happens even when the light object is not a conductor. The mechanism for how this happens is explained later in Sections 1.10 and 2.10.] The centres of the two types of charges are slightly separated. We know that opposite charges attract while similar charges repel. However, the magnitude of force depends on the distance between the charges and in this case the force of attraction overweighs the force of repulsion. As a result the particles like bits of paper or pith balls, being light, are pulled towards the rods.

Conductors And Insulators Physics || Class 12 Ncert || Class 12 Ncert Physics In Pdf || Notes For Defense Exams

Conductors And Insulators :

A metal rod held in hand and rubbed with wool will not show any sign of being charged. However, if a metal rod with a wooden or plastic handle is rubbed without touching its metal part, it shows signs of charging. Suppose we connect one end of a copper wire to a neutral pith ball and the other end to a negatively charged plastic rod. We will find that the pith ball acquires a negative charge. If a similar experiment is repeated with a nylon thread or a rubber band, no transfer of charge will take place from the plastic rod to the pith ball. Why does the transfer of charge not take place from the rod to the ball?

Some substances readily allow passage of electricity through them, others do not. Those which allow electricity to pass through them easily are called conductors. They have electric charges (electrons) that are comparatively free to move inside the material. Metals, human and animal bodies and earth are conductors. Most of the non-metals like glass, porcelain, plastic, nylon, wood offer high resistance to the passage of electricity through them. They are called insulators. Most substances fall into one of the two classes stated above*.

When some charge is transferred to a conductor, it readily gets distributed over the entire surface of the conductor. In contrast, if some charge is put on an insulator, it stays at the same place. You will learn why this happens in the next chapter.

This property of the materials tells you why a nylon or plastic comb gets electrified on combing dry hair or on rubbing, but a metal article like spoon does not. The charges on metal leak through our body to the ground as both are conductors of electricity.

When we bring a charged body in contact with the earth, all the excess charge on the body disappears by causing a momentary current to pass to the ground through the connecting conductor (such as our body). This process of sharing the charges with the earth is called grounding or earthing. Earthing provides a safety measure for electrical circuits and appliances. A thick metal plate is buried deep into the earth and thick wires are drawn from this plate; these are used in buildings for the purpose of earthing near the mains supply. The electric wiring in our houses has three wires: live, neutral and earth. The first two carry electric current from the power station and the third is earthed by connecting it to the buried metal plate. Metallic bodies of the electric appliances such as electric iron, refrigerator, TV are connected to the earth wire. When any fault occurs or live wire touches the metallic body, the charge flows to the earth without damaging the appliance and without causing any injury to the humans; this would have otherwise been unavoidable since the human body is a conductor of electricity.

Unification Of Electricity And Magnetism Physics In English || Class 12 Ncert Physics In Pdf || Ncert Pdf || Pdf Ncert Class 12th

Unification Of Electricity And Magnetism :

In olden days, electricity and magnetism were treated as separate subjects. Electricity dealt with charges on glass rods, cat’s fur, batteries, lightning, etc., while magnetism described interactions of magnets, iron filings, compass needles, etc. In 1820 Danish scientist Oersted found that a compass needle is deflected by passing an electric current through a wire placed near the needle. Ampere and Faraday supported this observation by saying that electric charges in motion produce magnetic fields and moving magnets generate electricity. The unification was achieved when the Scottish physicist Maxwell and the Dutch physicist Lorentz put forward a theory where they showed the interdependence of these two subjects. This field is called electromagnetism. Most of the phenomena occurring around us can be described under electromagnetism. Virtually every force that we can think of like friction, chemical force between atoms holding the matter together, and even the forces describing processes occurring in cells of living organisms, have its origin in electromagnetic force. Electromagnetic force is one of the fundamental forces of nature.

Maxwell put forth four equations that play the same role in classical electromagnetism as Newton’s equations of motion and gravitation law play in mechanics. He also argued that light is electromagnetic in nature and its speed can be found by making purely electric and magnetic measurements. He claimed that the science of optics is intimately related to that of electricity and magnetism.

The science of electricity and magnetism is the foundation for the modern technological civilisation. Electric power, telecommunication, radio and television, and a wide variety of the practical appliances used in daily life are based on the principles of this science. Although charged particles in motion exert both electric and magnetic forces, in the frame of reference where all the charges are at rest, the forces are purely electrical. You know that gravitational force is a long-range force. Its effect is felt even when the distance between the interacting particles is very large because the force decreases inversely as the square of the distance between the interacting bodies. We will learn in this chapter that electric force is also as pervasive and is in fact stronger than the gravitational force by several orders of magnitude (refer to Chapter 1 of Class XI Physics Textbook).

Electric Charge Physics || Physics Class 12ncert || Class 12 In Hindi PDF || Reasoning Tricks In Hindi

Electric Charge :

Historically the credit of discovery of the fact that amber rubbed with wool or silk cloth attracts light objects goes to Thales of Miletus, Greece, around 600 BC. The name electricity is coined from the Greek word elektron meaning amber. Many such pairs of materials were known which on rubbing could attract light objects like straw, pith balls and bits of papers.

You can perform the following activity at home to experience such an effect. Cut out long thin strips of white paper and lightly iron them. Take them near a TV screen or computer monitor. You will see that the strips get attracted to the screen. In fact they remain stuck to the screen for a while.

It was observed that if two glass rods rubbed with wool or silk cloth are brought close to each other, they repel each other [Fig. 1.1(a)]. The two strands of wool or two pieces of silk cloth, with

which the rods were rubbed, also repel each other. However, the glass rod and wool attracted each other. Similarly, two plastic rods rubbed with cat’s fur repelled each other [Fig. 1.1(b)] but attracted the fur. On the other hand, the plastic rod attracts the glass rod [Fig. 1.1(c)] and repel the silk or wool with which the glass rod is rubbed. The glass rod repels the fur.

If a plastic rod rubbed with fur is made to touch two small pith balls (now-a-days we can use polystyrene balls) suspended by silk or nylon thread, then the balls repel each other [Fig. 1.1(d)] and are also repelled by the rod. A similar effect is found if the pith balls are touched with a glass rod rubbed with silk [Fig. 1.1(e)]. A dramatic observation is that a pith ball touched with glass rod attracts another pith ball touched with plastic rod [Fig. 1.1(f )].

These seemingly simple facts were established from years of efforts and careful experiments and their analyses. It was concluded, after many careful studies by different scientists, that there were only two kinds of an entity which is called the electric charge. We say that the bodies like glass or plastic rods, silk, fur and pith balls are electrified. They acquire an electric charge on rubbing. The experiments on pith balls suggested that there are two kinds of electrification and we find that (i) like charges repel and (ii) unlike charges attract each other. The experiments also demonstrated that the charges are transferred from the rods to the pith balls on contact. It is said that the pith balls are electrified or are charged by contact. The property which differentiates the two kinds of charges is called the polarity of charge.

When a glass rod is rubbed with silk, the rod acquires one kind of charge and the silk acquires the second kind of charge. This is true for any pair of objects that are rubbed to be electrified. Now if the electrified glass rod is brought in contact with silk, with which it was rubbed, they no longer attract each other. They also do not attract or repel other light objects as they did on being electrified.

Thus, the charges acquired after rubbing are lost when the charged bodies are brought in contact. What can you conclude from these observations? It just tells us that unlike charges acquired by the objects neutralise or nullify each other’s effect. Therefore the charges were named as positive and negative by the American scientist Benjamin Franklin. We know that when we add a positive number to a negative number of the same magnitude, the sum is zero. This might have been the philosophy in naming the charges as positive and negative. By convention, the charge on glass rod or cat’s fur is called positive and that on plastic rod or silk is termed negative. If an object possesses an electric charge, it is said to be electrified or charged. When it has no charge it is said to be neutral.

अल्फा कण प्रकीर्णन का रदरफोर्ड सिद्धान्त (Rutherford's Principle Of Alpha 'α' Particles Scattering) Physics || Rutherford's Principle Of α - Particles Scattering Physics || Ratherford Ka Alpha Kan Prakirnan Ka Sidhant Physics || Alpha Kan Parkirnan Ka Rathrford Sidhant Physics || Physics Solution || Ncert Solution

अल्फा कण प्रकीर्णन का रदरफोर्ड सिद्धान्त
(Rutherford's Principle Of Alpha 'α' Particles Scattering)

अल्फा कण प्रकीर्णन का रदरफोर्ड सिद्धान्त :-

               अल्फा कण प्रकीर्णन का रदरफोर्ड सिद्धान्त:- धातु की पतली पर्णिकाओं के द्वारा α कणों के प्रकीर्णन के अध्ययन से रदरफोर्ड द्वारा परमाण्वीय नाभिक की खोज की गई।

                रदरफोर्ड के अनुसार α कणों का प्रकीर्णन α कणों के धन आवेश तथा अति मूल्य व्यास के नाभिक में केन्द्रित धन आवेश के बीच की अन्योन्य क्रियाओं के तुल्य होती है। धातु की पतली पर्णिकाओं के द्वारा α कणों से प्रकीर्णन की व्याख्या करने के लिये रदरफोर्ड ने परमाणु को निम्नलिखित अभिग्रहितों के साथ प्रस्तुत किया :-

1. परमाणु का सम्पूर्ण धन आवेश उसके केन्द पर केन्द्रित होता है, जिसे नाभिक कहते है।

2. नाभिक तथा α कण बिन्दु मात्र होते है या उनकी साईज नगण्य होती है।

3. α कणों की तुलना में नाभिक बहुत भारी होता है। अन्योन्य क्रिया के समय नाभिक गति नहीं करता है।

4. प्रकीर्णन केवल α कण एवं नाभिक के मध्य अन्योन्य क्रिया के कारण होता है। परमाणु में उपस्थित ऋण आवेशित इलेक्ट्रोनों का प्रभाव नगण्य होता है।

काॅम्पटन प्रभाव (Compton's Effect) Physics || Kompton Prabhav Physics || Compton Prabhav Physics || Compton Effect Physics || Physics Solution || Maths Guru || Ncert Solution

काॅम्पटन प्रभाव (Compton's Effect)

काॅम्पटन प्रभाव:- काॅम्पटन नामक वैज्ञानिक ने 1923 में अपने एक प्रयोग में ग्रेफाईट ब्लाॅक द्वारा प्रकीर्णित X किरणों की तरंगदैध्र्य दो प्रकार की प्राप्त होती है। एक तरंगदैध्र्य आपाती X किरणों के समान जबकि दूसरी तरंगदैध्र्य आपाती किरणों की तरंगदैध्र्य से अधिक होती है। प्रकीर्णित X किरणों की तरंगदैध्र्य के अन्तर को काॅम्पटन तरंगदैध्र्य या काॅम्पटन विस्थापन कहते है। उपर्युक्त प्रेक्षण को काॅम्पटन प्रभाव कहते है।

अन्य सम्बन्धित प्रभाव
प्रकाश वैद्युत प्रभाव (Photo Electric Effect)

प्रकाश वैद्युत प्रभाव (Photo Electric Effect) Physics || Prakash Vidhut Prabhav Physics || Light Electric Effect Physics || Prakash Vidhut Physics || Physics Solution || Maths Guru || Ncert Solution

प्रकाश वैद्युत प्रभाव (Photo Electric Effect)

प्रकाश वैद्युत प्रभाव:-
                              जब किसी धातु प्रष्ठ पर विशिष्ट आवृति का प्रकाश आपतित होता है तब प्रष्ठ से इलेक्ट्रोन उत्सर्जित होते है। यह प्रकाश वैद्युत प्रभाव कहलाता है।

           इस प्रकार उत्सर्जित इलेक्ट्रोनों को फोटो इलेक्ट्रोन तथा इन इलेक्ट्रोनों के कारण प्रवाहित विद्युत धारा को प्रकाश विद्युत धारा कहते है।
               इस प्रभाव में प्रयुक्त धातु जिससे इलेक्ट्रोन उत्सर्जित होते है, को फोटो इलेक्ट्रोन उत्सर्जक कहते है।

बरनौली प्रमेय के अनुप्रयोग (Bernoulli theorem application) || Barnoli Ki Prmey Physics || Bernoli Ki Permy Physics || Physics Solution || Ncert Solution

बरनौली प्रमेय के अनुप्रयोग
(Bernoulli theorem application)

बरनौली प्रमेय के अनुप्रयोग :-
(Bernoulli theorem application) :-

1. समान दिशा में अत्यन्त समीप गतिशील नावों अथवा बसों में आकर्षण (Very close to the same direction in dynamic boat or buses) :- 
                   जब दो नांव या बसें समान दिशा में अत्यन्त समीप तेजी से गतिशील होती है तो उनके मध्य जल या वायु की परतें तेजी से गतिशील हो जाती है जबकि दूर स्थित जल या वायु की परतें धीमी गति से चलती है। अतः बरनौली की प्रमेय से, उनके मध्य दाब कम हो जाता है। इस दाबान्तर के कारण ही वे एक - दूसरे की ओर खिंचती है।

2. वायुयान के पंखो की आकृति (Airplane wings) :-
                 बरनौली की प्रमेय के अनुसार किसी बहते हुए तरल में जहां वेग अधिक होता है वहां दाब कम होता है जहां वेग कम होता है वहां दाब अधिक होता है। इसका उपयोग वायुयान के पंखे बनाने में किया जाता है। पंखे की आकृति के कारण पंखे के उपरी तल की वायु का वेग नीचे के तल की वायु के वेग से अधिक होता है। फलस्वरूप उतरी तल पर वायु का दाब निचले तल की अपेक्षा कम हो जाता है। इसी दाबान्तर के कारण वायुयान को आवश्यक उत्थापक बल मिल जाता है।

3. कणित्र (Atomizer)(Knitra):-
                  कारबुरेटर, पेंटगन या सेंट स्प्रे की क्रियाविधी बरनौली प्रमेय पर आधारित है।

             इसमें एक पिचकारी होती है जिसके एक सिरे पर रबर का खोखला गोला तथा दूसरे सिरे पर बारीक छिद्र होता है। पिचकारी की नली के संकीर्णित भाग से एक केशनली लगा दी जाती है। जिसका निचला सिरा बर्तन में भरे द्रव में डूबा रहता है।

          जब पिचकारी की गेंद को दबाते है तो वायु क्षैतिज नली से होकर बाहर निकलती है। नली के संकीर्णित भाग में वायु का वेग अधिक होता है। जिसके कारण वहां दाब घट जाता है। दाब घटने से द्रव केशनली में उपर तक आकर वायु के साथ फुहार के रूप में बाहर निकलता है।

4. तेज आंधी में टिन की छतों का उड़ जाना।

5. मैग्नस प्रभाग (Magnus Division) (Megnas Prbhav) :-
            गेंद को चक्रण कराना।