HC Verma sir taught me this use of symmetry in a reply of a mail... "Why does the charge not experience a force due to its own electric field? " Sir, asked me in reply... "In which direction should the charge experience the force? " And I got my answer. This is a beautiful use of symmetry to answer a question and I learned it rom our dear HCV sir❤❤❤😊
@@sachinrajpandey5242 In which direction the charge would experience a force due to it's own field? No direction is special... So, the charge will not experience any force due to it's own field
best physics teacher ever seen and the Book he 🙏 wrote, his name (H.C.V )is more famous than the name of the book(Concepts of physics). Namaste sir 🙏🙏🙏
ix) The variation of bending moment in a beam, where load is UDL, is (a) linear (b) parabolic (c) cubic (d) zero (x) The variation of bending stress on a transverse plane of a beam is (a) linear (c) linear and nonlinear (b) nonlinear (d) Parabolic
(h) In a thin cylindrical shell closed at endis and experiencing internal fluidi pressure, the ratio of hoop stress and longitudinal stress is (i) 4:1 2. 3:1 3. 2:1 (iv) 1:2
My question is " Does a charge undergoing acceleration within a gravitational field emit radiation? " I have been thinking about this situation for quite some time since my 11th grade and could not come up with any possible answer. I have also asked this to many physics teachers and professors but could not get a satisfactory response. According to classical electromagnetism, an accelerating charge emits electromagnetic radiation. However this scenario touches upon the intersection of two fundamental theories in physics-electromagnetism and general relativity.
Sir i have a question that in gauss law and ampere circuital law we consider only charge inside guassian surface and current inside the ampere's loop respectively but electric field and magnetic field is due all charges and current inside and outside . Why so ?
Namaskar, I am Jagdish Prajapati, a 12th Science student from Pune. My doubt is- When a substance is used as a dielectric material and the capacitor gets charged then the dielectric material arranges its atomic poles to create an electric field opposite to that of charged plates, and that change in the electric field of dielectric material is called "Displacement current". If air is used as dielectric we can say that it has atoms to align with the field but "Vaccum" can act as a dielectric material too, it should also arrange its atomic poles in the way discussed above but a vacuum doesn't have atoms as we define vaccum. So what vacuum exactly is according to Physics and according to Philosophy?
Sir can you please explain me: 1) resistor in series 2) resistor in parallel I am a big fan of your physic's books and also yours....... I am an Allenite so this the doubt from my module.
Then sir, question arises that what is special about redial direction of this long charge distribution ( which you taken as example in last ) so that electric field is in redial direction with respect to given charge distribution.
In the derivation of "*magnification. m =-v/u we get this result by sign convention then why do we use the sign convention in problems if we use this relation*."
Dr.H.C.Verma sir from centuries students learning in schools and colleges blindly beleive that magnetic field lines move from North pole to South pole with out getting the reason for it.When I tried to get the reason I didn't receive it. So,I think you would give the answer to this question . A request for your follower 🙂
From maxwells equation of electromagnetism aka the rules that govern electromagnetism , We know magnetic field lines will from a closed loop . Now when any object will make its magnetic field loops must pass through the object(bcoz the magnetic field has originated from electrons of the object , so the loops must pass through the object) . Therfore the loops will cut the object at two point . We name these points as poles , One pole from which magnetic field "appear" to move out is called north and other south . It is just convention you can also call them idli and dosa . Also inside the object , the field moves from south to north to complete the loop .
hava ke na hone par kam mass ka or jyada mass ka object same time pe niche girte he , jyada mass vale object ka inertia jyada he, kam mass vale ka inertia kam he to dono sathme kyo girte he ???
As we know, by charging any body by friction, electron get transferred from one body and go to other body. So, one body get positively charge and other is negatively charge. So, how does this electron return to first body from where it would come? Or the body will permanently charge. Please sir tell what is really happen to electron
Sir can you please explain the question no 46 of chapter centre of mass ,linear momentum and collision of understanding physics book part 1 , please sir . Sir answer is given 6.1 but answer is coming 4.2 by work energy principal and 9.1 by conservation of mechanical energy
Sir I'm Abaneesh Mohapatra from odisha Rourkela of class 9 , I have a doubt In a concept of fluid mechanics I.e. A beaker is filled with water and a ice cube is partially floating in it and a coin is placed over it , after the ice melt, the water level decreases (why?) Thank you
We can assume , the volume of coin is very less as compared to ice . When coin is kept on ice . Ice is occupying volume greater than its mass so when it melts it is not able to compensate hence the water level decreases
Sir I am kartikey I am in class 9. My question is Q. How can atmospheric pressure apply inside a room because we are under the roof so the roof would have taken all the weight of the atmosphere but why does it apply inside a room?
Sir , in your book the first and second focus of concave and convex lens is defined in the basis of image and object i.e. the focus of retracted rays is 2nd focus and that of incident ray is 1st focus , but sir in class 10 NCERT the 2 focii of convex and concave lens are actually defined on the basis of 1st and 2nd surface of the lens , so sir which one shall be considered at school level , cause sir this year is our boards so please give solution
If forces are not equal then there might exist some resultant, isn't it? Please explain Sir. Also please Sir start online courses as earlier. Thank you.
(ii) Strain energy in torsion of a shaft/unit volume is given by: (a) q²/2G (b) q'/4G (c) q²/2E (d) q²/4E where Gmod of rigidity, E=mod of elasticity and q=she stress. (iii) A mild steel bar of uniform cross-section A and length L is su jected to an axial load W. The strain energy stored in the bar show be (a) WL/2AE (c) WL/4RE (b) W²L/4AE (d) W²L/2AE
As a 9th grader, I have some questions please : i) why doesn't the celestial objects orbiting around other celestial objects clash into each other according to the general theory ii) for instance, there is a book on the table if I push it to slide across the table meaning I exert force on it , shouldn't the book apply a reaction force and stay there according to Newton's third law of motion. If the third law of motion is true, how is unbalanced force a thing ??
sir i have a question we say that the internal reistance of a ideal ammeter is zero. so when we connect in the circuit to measure current flowing through it why doesnt it shows infinite according to V=IR
If a man is at rest and he saw that moving charge creates the magnetic field and women with same speed as the moving charge is travelling then for the man there is magnetic field and for women there is no magnetic field. As the moving charges create a magnetic field is a fundamental phenomenon of electromagnetism . So sir what will be your conclusion on it plz explain me
Sir I am Abhrajit Ghosh I have just passed 12th standard but I have really misconception (rather doubt) about frictions these are - When a man is walking friction is acted on him forward to make him walking and this force of friction is due to the push by the man on the ground in opposite direction but when the man exerts a force greater than the limiting value of static friction he slips but the ground should provide equal amount of force irrespective of friction according to thr 2nd law of Newton. So why the man slips? What about the action reaction pair? If ground exerts an equal and opposite force then why bothering of limiting value of static friction comes in to account? Sir I would be oblige if you please give an insight to this 🙏 Thankyou🙏🙏
The second law is talking about resultant force on the body. Friction is never a resultant force on a system under contact forces only. It's a horizontal component of net contact force by the floor. Normal reaction and friction are two mutually perpendicular force components of the net resultant force on a body when in relative motion. Being a horizontal component, you must understand that this component can increase or decrease. But the resultant contact force can't be all along horizontal direction as it is originated due to contact with the floor. Hence there will always a vertical component. Now this restrict the maximum value friction can have. Hence friction can vary but upto a limit only. After reaching that limit, it becomes constant what we know as kinetic friction. Third law of motion also talking about resultant force. The resultant force must be equal and opposite along the line of action. Your point is totally correct that force by floor on body and body on floor must be equal and opposite. But think of this, the body is at rest on the floor and so resultant contact force is only normal reaction. As you try to push or pull it horizontally, the net contact force inclines . A body when try to move or in constant motion but in contact with the floor, the net contact force is not vertical. There are actually 3 force on the body. One is normal reaction, one is you horizontal force, one is friction due to floor ( It can be just two force on the body if body is already in motion and you don't apply your force). Note here that your force can be of any value. And it has nothing to do with friction. The friction is not because you've applied a force horizontally, it is because bodies in motion don't have vertical contact force on them. Hence you foot is not only in contact with the floor. You are adding extra force in forward direction. That's why your forward force can be more than friction. At last i want to say that your statement "friction is due to push by foot" is not completely right. Ofcourse friction is due to contact but its value depend upon inclination of net contact force due to relative motion when in contact.
Sir I have just seen your advanced course in special theory of relativity. The lectures are very nice. But sir, I have a question. The drift velocity of electrons in a copper wire is about 0.02 cm/s (very small velocity). Then, how does the relativity come into play in describing the magnetic field?? Sir, please answer when possible. Thank you sir
We don't focus on drift velocity for magnetic field, bcoz that is the effective speed of electrons through a cross section , individual speed of electrons are very high and close to c , that's why
Hello sir I am Umair Naseer form Pakistan i often watch Indian teachers lecture from Physic Wallah and also some of your short video i come to know you answer the doubts of students sir i always have some doubts regarding physics.. sir i hooe you will clear it . Sir Q NO 1 .why centripetal force done no work( to whom i ask he just reply as angle between Force and displacement is 90 .... But I don't really understand logic behind this same is for magnetic force on a charge.. kindly explain it plz. And one last question whe know that magnetic force on a moving charge casue motional emf but what is phenomena behind mutual induction in other coil which is at reast plz sir answer these doubt i will bi highly thankful love from Pakistan ❤🇵🇰
Sir, I am a student of class 12 from West Bengal. I have a question. How is Displacement current generated from change in magnetic or electric flux? How does the phenomena rises? Means there must be a scientific explanation behind it? Before class 12, I thought that current can only flow through wire, but now I really want to know how this displacement current is getting aroused?
Displacement current is not a charge flow. The name of it was just coined by Maxwell to form an analogy between conventional current due to flow of charges. Time dependent changing magnetic field creates a new field in space. This new field is not at all electric field because this new field are closed in nature. But we call it electric field because many of the properties of it resembles that of electrostatic field, like it acts on charges whether at rest or motion. Now it's just the property of this new field that its time rate of change produces magnetic field. This magnetic field between the capacitor plates was detected by magnetic compass. The reason for why changing magnetic field produces this new field and vice-versa, is atleast not known to me. Your question is just like other questions that why moving charges produces magnetic field, why charges create electrostatic fields? Note: the existence of magnetic force is proved theoretically by special relativity theory and turns out to be a relativistic phenomenon. Although we use a charge distribution in that derivation, I don't know how it explains the phenomenon for a single moving particle affecting another charge.
hello sir my name is agastu yadav , my question is related to factors of prism .i am unable to understand the deviation vs incidence graph as in text book given directly the graph and on searching the proof comes of inter class which i am unable to understand .sir can you plz give me a basic understanding for this graph
Yes and no depending upon whether you're applying force on it or the body is at inclined plane . If you're applying a force and it is still at rest that means there is a static friction acting on the body (assuming horizontal floor). If you're not applying any force and body is at rest (assuming horizontal floor), that means there is no friction force on it. But if the floor is inclined in this case, there is a static friction balancing tangential component of weight.
I have dought , when spring systeam is in equilibrium and blocks are string by spring then strin of above block is cut then the block A will fall ? and block B in not fall still the A is come to its compration ?
Sir I am Swapnadeep De. I am a student of class ten of icse board. I have a question that what does the word 'charge' means? When we say electron is negatively charged or proton is positively charged, what do we exactly mean? Please clarify sir please 🙏🙏🙏🙏
What is "length" ? What is "time" ? What is "mass"? these all are questions which cannot be answered in entirety . That is because they are defined by us humans . We define length as a "physical quantity" that "quantifies" the space taken by an object . Similarly , mass is a "physical quantity" that "quantifies" the "inertia" of an object . Now , you may get what I am saying . Similarly , Charge is a physical quantity that quantifies the amount of force experienced by it in an electromagnetic field . Depending on the direction of force experienced , there were 2 kinds of charges , and they were named as positive and negative , its just convention you can also call them hot or cold ,
Sir i have a question "what is the capacitance of a short circuited capacitor" i have asked many teachers but i am not satisfied with their answer so please please and please answer it 🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏
bro stay in your aukaat and first get to know whom you are asking this question to........ verma sir wont and will never make videos on jee instead he just focuses on concepts and knowledge that too not from jee but from the beautiful subject PHYSICS
The total area under the stress-strain curve of a mild steel speci- men test up to failure under tension is a measure of its (a) breaking strength (b) hardness (c) stiffness (d) toughness
A bar of copper and steel form a composite system. They are cooled to a temperature of 25°C. What type of stress is induced in the copper bar? (a) Tensile (b) Compressive (c) Tensile as well as compressive (d) Shear
Q.4.A shaft is to be designed on the basis of (a) maximum allowable shear stress (b) maximum allowable angle of twist (c) both (i) and (ii) (d) torsional rigidity
Respected sir, Does all forces exist in the universe are because of matter.......is there something else....... Sir can we found out the forces on the frame of reference , in which we are also a part of it....If it is then we can know the acceleration caused by the force of time..........i think ,time is also a force and it causes constant acceleration on every object at the rest but a different on the moving.... Can time force exist without space or it is impossible???????
1. No , most of the forces are due to "field" . Electric field , magnetic field , gravitational field . Bodies interact with field to transfer energy which causes the existence of force . 2. We can know the acceleration of the system in which we are also part of , by knowing your acceleration when you are on it . 3. Times causes no acceleration , over time the object remain in same place so time causes no accn . It can also be seen by law of inertia . 4. Thinking that time is force is itself wrong , bcoz force is defined as the rate of change of momentum w.r.t. to time . 5. Time force can never exist ,and analogy is wrong
Hello Sir I am class 10 student and have two doubts 1.) As we know light is made of photons which are particles and as per law of conservation of mass,mass can neither be created nor be destroyed then how does a laser light emit the light till infinity? 2.) Wires have really small cross section area which means really high resistance so why dont we use thick wires as this would decrease the resistance? Please sir help me out I am really confused Please sir I am really
The answers are 1) light is not a usual particle having mass. Another thing is that law of conservation of mass is not true. Matter can be created and destroyed. What remain conserved is energy. Mass is a form of energy just like kinetic energy is one form of energy. You need specific conditions to convert energy into mass and vice-versa. So light is a form of energy rather than a mass particle. 2) we use different kind of wires depending upon our needs. It's all upto you what kind of work you want to do with wires. Different appliances have a rating on which they can operate. Otherwise the appliance can be damaged.
Good morning respected sir. I am divyanshu of class 12 and i have a doubt regarding to special theory of relativity as we all know photon travel with the speed of light but sir we also know that if something has energy as well as momentum it also have mass.. Therefore photon also have mass then how photon travel with the speed of light. I have asked this question multiple times in the Institute they don't gave me the answer. I would very thankful to you if you reply
There's a relation between total energy of a free particle and its linear momentum in special theory of relativity. In classical physics, we say that any free point particle can only have kinetic energy as its total energy. This thing is not true in high speeds. E²=(pc)²+(MoC)² is the relation I'm talking about. You can easily derive it. Now since photon has no mass, E=pc. Why these terms are not zero? Because we know that Energy of a photon can't be zero. Therefore p=E/c. A photon can have momentum without having mass!! Definition of momentum changes as we go at higher speeds. The formula for momentum in classical physics was just an empirical result (by observing the impact of mass on collisions). But in special theory of relativity, conservation of momentum is not valid in classical expression. So we modified definition of momentum according to collected evidence and postulates of relativity. It's a fact came from relativity theory that mass is not independent of energy. Mass is just some form of energy like kinetic energy and potential energy. They have their own significance and results and so does mass.
Sir I am from Kolkata. I am in class 12.can you make a video on this because I have searched in many websites and also TH-cam but I haven't got the answer yet . The question is:- does the focal length of the concave lens increase or decrease when it is immersed in water?
If the refractive index of concave lens material is same as of water focal length will become infinitely long. If fecal length of concave lens material is a bit more than that of water then the concave lens will still act as a concave lens but of larger focal length than it will show in air. If refractive index of concave lens material is less than water then it will acts as convex lens . So the less the difference between R.I . any lens material and the R.I. of medium in which it is used the more will be focal length.
Sir I have a doubt, why light intensity has a relation with amplitude, as we know amplitude is the maximum displacement of particles from it's mean position so why if amplitude of a light decreases then it's intensity also decreases and vice versa, because in my book there's a diagram which is showing refraction of ray,so in that there is partial reflection and refraction of light,so in that they have written " the refracted ray is not as brighter as incident ray because part of it get reflected" they have mentioned that amplitude is changed that's why Sir please solve my question, This is bothering me a lot, so please make a video on this and explain to me what is happening exactly.
When light stikes the boundary of two medium , it is reflected , refracted and transmitted . Frequency of all these are same . Now , lets talk about their amplitude , there amplitude will off course change . Bcoz the sum of energy has to remain same as initially , reflected and refracted ray will have some portion of it . Sometimes most portion is reflected(mirror} and sometimes less portion is reflected(refraction through glass slab) . Also , amplitude for light is not the displacement of "particles" , it is maximum value of "electric field" and these value of electric field will obviously depend on properties of material
Philosophical argument to approach a solution for a Numerical Problem always Fascinates students 👏
HC Verma sir taught me this use of symmetry in a reply of a mail...
"Why does the charge not experience a force due to its own electric field? "
Sir, asked me in reply... "In which direction should the charge experience the force? "
And I got my answer. This is a beautiful use of symmetry to answer a question and I learned it rom our dear HCV sir❤❤❤😊
Thanks for sharing.
Which email address can you pls tell it
What is the answer of charge not experiencing force due to its own electric field?
@@sachinrajpandey5242 In which direction the charge would experience a force due to it's own field?
No direction is special... So, the charge will not experience any force due to it's own field
@@ArnabNature thanks for your answer, will Sir starting any online courses like earlier.
Best physics teacher ever seen
For me it is prof. Walter lewin
Who asked? @ishaansharma2278
Duhhh
@@Padhai_Kar_Jakebut you answered 🤡
@@nowheretorun191 usse reply karna kehte hai
best physics teacher ever seen and the Book he 🙏 wrote, his name (H.C.V )is more famous than the name of the book(Concepts of physics). Namaste sir 🙏🙏🙏
Best Physics Teacher who can answer any question related to his topic❤
ix)
The variation of bending moment in a beam, where load is UDL,
is
(a) linear
(b) parabolic
(c) cubic
(d) zero
(x)
The variation of bending stress on a transverse plane of a beam
is
(a) linear
(c) linear and nonlinear
(b) nonlinear
(d) Parabolic
That is why one minutes of listening to a legend of philosophy of physics is of more worth than listening to MCQ microphone for hours. !
Sir I'm working on a project related to Symmetry and I'm really impressed from this kind of argument u made on Symmetry ( new fan sir 💪🏻😎 )
One of the Greatest teacher in world😊😊😊😊😊
He has amazing ability to teach such interesting thing from a really bad question ( which is actually a homework problem)
Hmmmm Interesting.... the way you tackled the question,And how you argued.
(h) In a thin cylindrical shell closed at endis and experiencing internal fluidi pressure, the ratio of hoop stress and longitudinal stress is
(i) 4:1
2. 3:1
3. 2:1
(iv) 1:2
ix) Castigliano's theorem is valid for
(a) any structure (c) linear structure (b) non-linear structure (d) Any of the above
Sir, I wish for your good health and long life. Physics is so beautiful because of you.
My question is " Does a charge undergoing acceleration within a gravitational field emit radiation? " I have been thinking about this situation for quite some time since my 11th grade and could not come up with any possible answer. I have also asked this to many physics teachers and professors but could not get a satisfactory response. According to classical electromagnetism, an accelerating charge emits electromagnetic radiation. However this scenario touches upon the intersection of two fundamental theories in physics-electromagnetism and general relativity.
Sir i have a question that in gauss law and ampere circuital law we consider only charge inside guassian surface and current inside the ampere's loop respectively but electric field and magnetic field is due all charges and current inside and outside . Why so ?
Sir Great ❤😊🙏 शिक्षक दिवस की शुभकामनाएँ सर ❤
What electron always (every time) revolves around Nucleus
Love from Bihar sir ❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤
HC Verma sir ap mere school me ane wale hai
Sir please answers the question ''why the direction of angular velocity, acceleration, momentum is perpendicular to plane? "
Sir please make us leactures on chapters of physics 11th and 12th for jee main/advanced and neet ❤❤
Namaskar, I am Jagdish Prajapati, a 12th Science student from Pune.
My doubt is-
When a substance is used as a dielectric material and the capacitor gets charged then the dielectric material arranges its atomic poles to create an electric field opposite to that of charged plates, and that change in the electric field of dielectric material is called "Displacement current". If air is used as dielectric we can say that it has atoms to align with the field but "Vaccum" can act as a dielectric material too, it should also arrange its atomic poles in the way discussed above but a vacuum doesn't have atoms as we define vaccum. So what vacuum exactly is according to Physics and according to Philosophy?
Sir I am studying in cls 10
I have a question that how potential difference creat current in a conducting wire
Sir aap physics ki coaching krrayenge aapke Jaise teacher khii nhi mil skte
How electron moves from where it gets the energy to move ?
Sir can you please explain me:
1) resistor in series
2) resistor in parallel
I am a big fan of your physic's books and also yours.......
I am an Allenite so this the doubt from my module.
Sale ye to basic h
9th-10th me hi bta dete h ye sb
Kya re bc
Bro it isn't a doubt, it's a topic😅
What is eletron cloud...how we can see electron
Then sir, question arises that what is special about redial direction of this long charge distribution ( which you taken as example in last ) so that electric field is in redial direction with respect to given charge distribution.
In the derivation of "*magnification. m =-v/u we get this result by sign convention then why do we use the sign convention in problems if we use this relation*."
Dr.H.C.Verma sir from centuries students learning in schools and colleges blindly beleive that magnetic field lines move from North pole to South pole with out getting the reason for it.When I tried to get the reason I didn't receive it. So,I think you would give the answer to this question . A request for your follower 🙂
From maxwells equation of electromagnetism aka the rules that govern electromagnetism , We know magnetic field lines will from a closed loop . Now when any object will make its magnetic field loops must pass through the object(bcoz the magnetic field has originated from electrons of the object , so the loops must pass through the object) . Therfore the loops will cut the object at two point . We name these points as poles , One pole from which magnetic field "appear" to move out is called north and other south . It is just convention you can also call them idli and dosa . Also inside the object , the field moves from south to north to complete the loop .
Please please make vidoes on Lagrange and Hamiltonian mechanics
hava ke na hone par kam mass ka or jyada mass ka object same time pe niche girte he , jyada mass vale object ka inertia jyada he, kam mass vale ka inertia kam he to dono sathme kyo girte he ???
As we know, by charging any body by friction, electron get transferred from one body and go to other body. So, one body get positively charge and other is negatively charge. So, how does this electron return to first body from where it would come? Or the body will permanently charge. Please sir tell what is really happen to electron
The body when comes in contact of any other object , it will aquire the electrons
So great Teacher!!
Sir I have a doubt. Please explain why voltage remains same in parallel connection and why isn't it same in series?
Sir can you please explain the question no 46 of chapter centre of mass ,linear momentum and collision of understanding physics book part 1 , please sir .
Sir answer is given 6.1 but answer is coming 4.2 by work energy principal and 9.1 by conservation of mechanical energy
Great one
Sir I'm Abaneesh Mohapatra from odisha Rourkela of class 9 , I have a doubt In a concept of fluid mechanics
I.e.
A beaker is filled with water and a ice cube is partially floating in it and a coin is placed over it , after the ice melt, the water level decreases (why?)
Thank you
We can assume , the volume of coin is very less as compared to ice . When coin is kept on ice . Ice is occupying volume greater than its mass so when it melts it is not able to compensate hence the water level decreases
@@iuoyo4707 thanks brother
Sir I am kartikey I am in class 9. My question is
Q. How can atmospheric pressure apply inside a room because we are under the roof so the roof would have taken all the weight of the atmosphere but why does it apply inside a room?
Sir please cover class 11 physics we need it...❤
Very well explained Sir.
Sir please explain moving wedge problem in chapter NLM
Sir , in your book the first and second focus of concave and convex lens is defined in the basis of image and object i.e. the focus of retracted rays is 2nd focus and that of incident ray is 1st focus , but sir in class 10 NCERT the 2 focii of convex and concave lens are actually defined on the basis of 1st and 2nd surface of the lens , so sir which one shall be considered at school level , cause sir this year is our boards so please give solution
Are you doing Xth HCV?
The defination in HCV is more accurate and correct and also universal . 1st surface and 2nd surface can change w.r.t. your point of view
If forces are not equal then there might exist some resultant, isn't it? Please explain Sir. Also please Sir start online courses as earlier. Thank you.
Yes
(ii)
Strain energy in torsion of a shaft/unit volume is given by:
(a) q²/2G
(b) q'/4G
(c) q²/2E
(d) q²/4E
where Gmod of rigidity, E=mod of elasticity and q=she
stress.
(iii) A mild steel bar of uniform cross-section A and length L is su jected to an axial load W. The strain energy stored in the bar show
be
(a) WL/2AE
(c) WL/4RE
(b) W²L/4AE
(d) W²L/2AE
As a 9th grader, I have some questions please :
i) why doesn't the celestial objects orbiting around other celestial objects clash into each other according to the general theory
ii) for instance, there is a book on the table if I push it to slide across the table meaning I exert force on it , shouldn't the book apply a reaction force and stay there according to Newton's third law of motion. If the third law of motion is true, how is unbalanced force a thing ??
What video on law of motion
Sir i have a question from integration how to integrate (sinx)^x this function.
Sir, is there any point experiencing zero force or zero resultant force in the existence ?
Hoping to meet you at iit❤
Sir why current does not follows the law of vector addition ?
❤ from Balurghat sir
sir i have a question
we say that the internal reistance of a ideal ammeter is zero. so when we connect in the circuit to measure current flowing through it why doesnt it shows infinite according to V=IR
Sir pls can u make a video on E=mc²
I don't know what exactly it
confusing from so many explanation I heard in u tube
If a man is at rest and he saw that moving charge creates the magnetic field and women with same speed as the moving charge is travelling then for the man there is magnetic field and for women there is no magnetic field. As the moving charges create a magnetic field is a fundamental phenomenon of electromagnetism .
So sir what will be your conclusion on it plz explain me
sir I have a quastion koi vastu 20m/s se jati h aur 25m/s se aati h to evrage speed kay hogi
formula :- 2.v1.v2upon v1+v2
isse bnega sir ?
Thank you sir 🙏
Sir, does heating capacitors generates electric current?
Sir I am Abhrajit Ghosh I have just passed 12th standard but I have really misconception (rather doubt) about frictions these are -
When a man is walking friction is acted on him forward to make him walking and this force of friction is due to the push by the man on the ground in opposite direction but when the man exerts a force greater than the limiting value of static friction he slips but the ground should provide equal amount of force irrespective of friction according to thr 2nd law of Newton. So why the man slips? What about the action reaction pair? If ground exerts an equal and opposite force then why bothering of limiting value of static friction comes in to account?
Sir I would be oblige if you please give an insight to this 🙏 Thankyou🙏🙏
The second law is talking about resultant force on the body. Friction is never a resultant force on a system under contact forces only. It's a horizontal component of net contact force by the floor. Normal reaction and friction are two mutually perpendicular force components of the net resultant force on a body when in relative motion.
Being a horizontal component, you must understand that this component can increase or decrease. But the resultant contact force can't be all along horizontal direction as it is originated due to contact with the floor. Hence there will always a vertical component.
Now this restrict the maximum value friction can have. Hence friction can vary but upto a limit only. After reaching that limit, it becomes constant what we know as kinetic friction.
Third law of motion also talking about resultant force. The resultant force must be equal and opposite along the line of action. Your point is totally correct that force by floor on body and body on floor must be equal and opposite. But think of this, the body is at rest on the floor and so resultant contact force is only normal reaction. As you try to push or pull it horizontally, the net contact force inclines . A body when try to move or in constant motion but in contact with the floor, the net contact force is not vertical. There are actually 3 force on the body. One is normal reaction, one is you horizontal force, one is friction due to floor ( It can be just two force on the body if body is already in motion and you don't apply your force).
Note here that your force can be of any value. And it has nothing to do with friction. The friction is not because you've applied a force horizontally, it is because bodies in motion don't have vertical contact force on them.
Hence you foot is not only in contact with the floor. You are adding extra force in forward direction. That's why your forward force can be more than friction.
At last i want to say that your statement "friction is due to push by foot" is not completely right. Ofcourse friction is due to contact but its value depend upon inclination of net contact force due to relative motion when in contact.
Our legend is getting older day by day 😓🥲
Sir I have just seen your advanced course in special theory of relativity. The lectures are very nice. But sir, I have a question.
The drift velocity of electrons in a copper wire is about 0.02 cm/s (very small velocity). Then, how does the relativity come into play in describing the magnetic field??
Sir, please answer when possible.
Thank you sir
We don't focus on drift velocity for magnetic field, bcoz that is the effective speed of electrons through a cross section , individual speed of electrons are very high and close to c , that's why
Sir Mera ek question ❓ hai bata dijiye ga JEE ke hai
Sir do you know Nawsad Ansari sir he is my teacher in jee prep in this time
Thanks Sir
Hello sir I am Umair Naseer form Pakistan i often watch Indian teachers lecture from Physic Wallah and also some of your short video i come to know you answer the doubts of students sir i always have some doubts regarding physics.. sir i hooe you will clear it . Sir Q NO 1 .why centripetal force done no work( to whom i ask he just reply as angle between Force and displacement is 90 .... But I don't really understand logic behind this same is for magnetic force on a charge.. kindly explain it plz.
And one last question whe know that magnetic force on a moving charge casue motional emf but what is phenomena behind mutual induction in other coil which is at reast plz sir answer these doubt i will bi highly thankful love from Pakistan ❤🇵🇰
Bcuz dot product is being used in work so
w=FORCE*DISPLACEMENT*COStheta
as theta=90 degree cos90=0
hence w=0
Sir I have a doubt
60-30=30 why it is equal to 30
Please tell sir
A man who tought physics to many indians 🤓
Sir, I am a student of class 12 from West Bengal. I have a question. How is Displacement current generated from change in magnetic or electric flux? How does the phenomena rises? Means there must be a scientific explanation behind it? Before class 12, I thought that current can only flow through wire, but now I really want to know how this displacement current is getting aroused?
Displacement current is not a charge flow. The name of it was just coined by Maxwell to form an analogy between conventional current due to flow of charges.
Time dependent changing magnetic field creates a new field in space. This new field is not at all electric field because this new field are closed in nature. But we call it electric field because many of the properties of it resembles that of electrostatic field, like it acts on charges whether at rest or motion. Now it's just the property of this new field that its time rate of change produces magnetic field. This magnetic field between the capacitor plates was detected by magnetic compass.
The reason for why changing magnetic field produces this new field and vice-versa, is atleast not known to me.
Your question is just like other questions that why moving charges produces magnetic field, why charges create electrostatic fields?
Note: the existence of magnetic force is proved theoretically by special relativity theory and turns out to be a relativistic phenomenon. Although we use a charge distribution in that derivation, I don't know how it explains the phenomenon for a single moving particle affecting another charge.
hello sir my name is agastu yadav , my question is related to factors of prism .i am unable to understand the deviation vs incidence graph as in text book given directly the graph and on searching the proof comes of inter class which i am unable to understand .sir can you plz give me a basic understanding for this graph
Hlo sir i sujal student of jee i have critical doubt in physics in chapter center of mass
0ne ball in air it came backe whith how many force of enervy
Sir l am unable to understand physics of class 11 also
sir please explain that when temperature increase why the length decreases
Bhai temperature aur length dono directly proportional hai na dono badega na
Sir my question is that an object at rest,is it having any force of frictuon.Please answer my question.
Yes and no depending upon whether you're applying force on it or the body is at inclined plane .
If you're applying a force and it is still at rest that means there is a static friction acting on the body (assuming horizontal floor).
If you're not applying any force and body is at rest (assuming horizontal floor), that means there is no friction force on it.
But if the floor is inclined in this case, there is a static friction balancing tangential component of weight.
I have dought , when spring systeam is in equilibrium and blocks are string by spring then strin of above block is cut then the block A will fall ? and block B in not fall still the A is come to its compration ?
I an omkar more
Sir I am Swapnadeep De. I am a student of class ten of icse board. I have a question that what does the word 'charge' means? When we say electron is negatively charged or proton is positively charged, what do we exactly mean? Please clarify sir please 🙏🙏🙏🙏
What is "length" ? What is "time" ? What is "mass"? these all are questions which cannot be answered in entirety . That is because they are defined by us humans . We define length as a "physical quantity" that "quantifies" the space taken by an object . Similarly , mass is a "physical quantity" that "quantifies" the "inertia" of an object . Now , you may get what I am saying . Similarly , Charge is a physical quantity that quantifies the amount of force experienced by it in an electromagnetic field . Depending on the direction of force experienced , there were 2 kinds of charges , and they were named as positive and negative , its just convention you can also call them hot or cold ,
Sir my question is
Can we apply newtons 3rd low to the gravitational force ? How
yes , obviously
Sir i have a question
"what is the capacitance of a short circuited capacitor"
i have asked many teachers but i am not satisfied with their answer so please please and please answer it 🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏
How to send questiins to sir?
Sir please start JEE Advanced crash course series. You will completely rock in such series.❤
bro stay in your aukaat and first get to know whom you are asking this question to........ verma sir wont and will never make videos on jee instead he just focuses on concepts and knowledge that too not from jee but from the beautiful subject PHYSICS
SIR WHAT IS THE DIFFERENCE BETWEEN TOTAL INTERNAL REFRACTION AND INTERNAL REFRACTION?
I really didn't got why you wrote total internal refraction .
I don't know about it does it even exist as total internal reflection.
Refraction occurs when light moves from one medium to another. So how *total internal refraction* ever exist?
Sir किरचॉफ ke niyam or video bna do
Law of motion
Sir Doubts question solving...
Q.1.
The total area under the stress-strain curve of a mild steel speci- men test up to failure under tension is a measure of its
(a) breaking strength
(b) hardness
(c) stiffness
(d) toughness
Q.2.
A bar of copper and steel form a composite system. They are cooled to a temperature of 25°C. What type of stress is induced in the copper bar?
(a) Tensile
(b) Compressive
(c) Tensile as well as compressive (d) Shear
Q.3.The planes of maximum normal stresses are inclined at an angle
of degree to the plane of pure shear
Q.4.A shaft is to be designed on the basis of
(a) maximum allowable shear stress
(b) maximum allowable angle of twist
(c) both (i) and (ii)
(d) torsional rigidity
Respected sir,
Does all forces exist in the universe are because of matter.......is there something else.......
Sir can we found out the forces on the frame of reference , in which we are also a part of it....If it is then we can know the acceleration caused by the force of time..........i think ,time is also a force and it causes constant acceleration on every object at the rest but a different on the moving....
Can time force exist without space or it is impossible???????
1. No , most of the forces are due to "field" . Electric field , magnetic field , gravitational field . Bodies interact with field to transfer energy which causes the existence of force .
2. We can know the acceleration of the system in which we are also part of , by knowing your acceleration when you are on it .
3. Times causes no acceleration , over time the object remain in same place so time causes no accn . It can also be seen by law of inertia .
4. Thinking that time is force is itself wrong , bcoz force is defined as the rate of change of momentum w.r.t. to time .
5. Time force can never exist ,and analogy is wrong
I am studing in 8th and i have a doubt that 5-5+5×5÷0 =-infinity sir aisa google calculator mai kyu ata hai what is the reason ?
@harsh_will_iit but why it is shown -infinity instead of infinity?
th-cam.com/users/shortsoXi5MkeUOCQ?si=WpX_K0Qfcne12pe4
This short will answer your question
Hello Sir I am class 10 student and have two doubts
1.) As we know light is made of photons which are particles and as per law of conservation of mass,mass can neither be created nor be destroyed then how does a laser light emit the light till infinity?
2.) Wires have really small cross section area which means really high resistance so why dont we use thick wires as this would decrease the resistance?
Please sir help me out I am really confused
Please sir I am really
The answers are
1) light is not a usual particle having mass. Another thing is that law of conservation of mass is not true. Matter can be created and destroyed. What remain conserved is energy. Mass is a form of energy just like kinetic energy is one form of energy. You need specific conditions to convert energy into mass and vice-versa. So light is a form of energy rather than a mass particle.
2) we use different kind of wires depending upon our needs. It's all upto you what kind of work you want to do with wires. Different appliances have a rating on which they can operate. Otherwise the appliance can be damaged.
I have doubt of your book hc verma class 11 can I tell doubt??
debaswa daimary , STUDENT
from ASSAM
Sir where to ask questions
Good morning respected sir.
I am divyanshu of class 12 and i have a doubt regarding to special theory of relativity as we all know photon travel with the speed of light but sir we also know that if something has energy as well as momentum it also have mass..
Therefore photon also have mass then how photon travel with the speed of light.
I have asked this question multiple times in the Institute they don't gave me the answer.
I would very thankful to you if you reply
There's a relation between total energy of a free particle and its linear momentum in special theory of relativity.
In classical physics, we say that any free point particle can only have kinetic energy as its total energy. This thing is not true in high speeds.
E²=(pc)²+(MoC)² is the relation I'm talking about. You can easily derive it.
Now since photon has no mass, E=pc. Why these terms are not zero? Because we know that Energy of a photon can't be zero. Therefore p=E/c. A photon can have momentum without having mass!!
Definition of momentum changes as we go at higher speeds. The formula for momentum in classical physics was just an empirical result (by observing the impact of mass on collisions).
But in special theory of relativity, conservation of momentum is not valid in classical expression. So we modified definition of momentum according to collected evidence and postulates of relativity.
It's a fact came from relativity theory that mass is not independent of energy. Mass is just some form of energy like kinetic energy and potential energy. They have their own significance and results and so does mass.
Sir mujhe apse milne ke liye kha ana hoga pls Sir 🙏
What the gmail ID of Sir HC Verma can anyone tell
Hello sir I am Shah faisal from class10th have question that how sun is burned without oxygen thank you sir ❤❤
Sir sir please help me
Mujhe numerical karne me bahot dikat aati he
Help me in hindi
Please sir answer
Sir class 12 ka one shot har chapter ka lecture upload karo na please 😢
Sir I am from Kolkata. I am in class 12.can you make a video on this because I have searched in many websites and also TH-cam but I haven't got the answer yet .
The question is:-
does the focal length of the concave lens increase or decrease when it is immersed in water?
If the refractive index of concave lens material is same as of water focal length will become infinitely long.
If fecal length of concave lens material is a bit more than that of water then the concave lens will still act as a concave lens but of larger focal length than it will show in air.
If refractive index of concave lens material is less than water then it will acts as convex lens .
So the less the difference between R.I . any lens material and the R.I. of medium in which it is used the more will be focal length.
Sir I have a doubt, why light intensity has a relation with amplitude, as we know amplitude is the maximum displacement of particles from it's mean position so why if amplitude of a light decreases then it's intensity also decreases and vice versa, because in my book there's a diagram which is showing refraction of ray,so in that there is partial reflection and refraction of light,so in that they have written " the refracted ray is not as brighter as incident ray because part of it get reflected" they have mentioned that amplitude is changed that's why
Sir please solve my question, This is bothering me a lot, so please make a video on this and explain to me what is happening exactly.
When light stikes the boundary of two medium , it is reflected , refracted and transmitted . Frequency of all these are same . Now , lets talk about their amplitude , there amplitude will off course change . Bcoz the sum of energy has to remain same as initially , reflected and refracted ray will have some portion of it . Sometimes most portion is reflected(mirror} and sometimes less portion is reflected(refraction through glass slab) . Also , amplitude for light is not the displacement of "particles" , it is maximum value of "electric field" and these value of electric field will obviously depend on properties of material
@@iuoyo4707 thank you so much