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High School/JEE/NEET/IPhO Physics | 17-19 Yrs

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  1.  
    2. Plz upload this video
    4 months ago by

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  2.  
    3. Good
    1 years ago by

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  3.  
    4. It does not appear to be easy to find r not, the distance of closest approach !. V Rama Rao
    1 years ago by vrama rao

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  4.  
    5. three concentric spherical conductors 1,2,3 of radii a, 2a and 3a have charges -Q, 2Q, and -4Q respectively. if r is the distance of the point under consideration from the center of the spheres, if we connect the conductors 1 and 2, 2 and 3, 1 and 3, 1 and ground, 2 and ground, and 3 and ground, separately, find the charge flown in each case. please help me solve the above problem
    2 years ago by

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  5.  
    6. dhanyawaad _/\_
    2 years ago by

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  6.  
    7. Electric Potential is undefined when Electric Field is absent. Shouldn't the Electric Potential at the centre of the Ring be Zero as Electric Field is absent at the centre? Please help me with this
    2 years ago by

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  7.  
    8. sir I am not getting ,why 10sin30 degree?
    2 years ago by idul ahmed

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  8.  
    9. in couple net torque is zero or not as force are antiparalel?
    3 years ago by abdul
    Ans 1 ->
    in couple, net force is zero, net torque will never be zero
    3 years ago by Thejas

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  9.  
    10. sir,in the Expression of energy conservation why equal to sign is present? if the velocity of charge q at C would be zero then how would it be able to penetrate through the sphere?
    3 years ago by Aishwary Pratap Singh

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  10.  
    11. sir i feel quset question difficult is they are advance level can i found their solution
    4 years ago by basu jain

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  11.  
    12. why cannot cos theta =-1/v2?
    4 years ago by Swapnil Aggarwal

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  12.  
    13. very good teaching sir , Thank u But small question sir,the solved examples are for jee mains or jee advanced
    4 years ago by Mani Kiran

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  13.  
    14. Sir how net electric field just outside the metal body is sigma/eo ? I have watched all videos before this .....can u mention in which module number u have taught this ?
    4 years ago by Sridhar Usha Rani
    Ans 1 ->
    Ofcourse for a sphere it is valid sir !...but how for all metal bodies ? Just mention the module number in which u have taught that electric field just outside the metal body is sigma/eo
    4 years ago by Sridhar Usha Rani

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  14.  
    15. sir,since charges are also present on the metal surface, wont there be 2 pressures--one due to external EF and the other due to the charges on the surface ?????
    5 years ago by nihal anwar

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  15.  
    16. Sir what does -ve sign indicates for potential energy?
    5 years ago by Dharamjeet Singh

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  16.  
    17. Sir why we are not using F = - dU/dr, instead F = dU/dr ??
    5 years ago by Dharamjeet Singh

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  17.  
    18. Is all uniformly charged body produces uniform electric field if yes then why uniformly charged ring not produces uniform electric field. Or which type of body produces uniform electric field
    5 years ago by Ashish tripathi

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  18.  
    19. Is all uniformly charged body produces uniform electric field if yes then why uniformly charged ring not produces uniform electric field. Or which type of body produces uniform electric field
    5 years ago by Ashish tripathi

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  19.  
    20. Work done by field is V initial -V final or V final -V initial please elaborate
    5 years ago by Ashish tripathi

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  20.  
    21. sir kya me NEET ke liye apke video pe fully dependent ho sakta hu... plzz reply
    5 years ago by Avinash Kumar

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  21.  
    22. Sir we conserved energy in case 1.But will the charge not be considered an ext force?
    5 years ago by Spandan Misra

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  22.  
    23. sir how did you calculate d
    5 years ago by Md Zakie Akhtar Ansari

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  23.  
    24. Dear Sir, After further simplifications and checking with other sources I am getting the general formula as V = KpCos? / r^2 Regards
    5 years ago by Utsav Negi

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  24.  
    25. Sir at 5:30 why did the -ve sign came .
    5 years ago by Harshvardhan

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  25.  
    26. Sir, how the positive charge has higher potential, and how did you govern the direction of electric field
    5 years ago by Harshit Sangwan

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  26.  
    27. sir how did u take that angle as 60 can u explain me clearly please
    5 years ago by SIVA CHUNDI

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  27.  
    28. Sir simply potential of drop means its talken about the potential at which point.......thanks in advance
    6 years ago by Prakash Raj
    Ans 1 ->
    it means electric potential of each drop
    5 years ago by Md Zakie Akhtar Ansari

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  28.  
    29. sir...in the above video u told "the above is valid for hollow uniformly charged shell also......is it applicable to both hollow metal and hollow nonconducting??............Thanks in advance? REPLY
    6 years ago by Prakash Raj

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  29.  
    30. Respected sir as potential is defined for a point in an electric field so how here potential is nonzero even if electric field is zero at center
    6 years ago by Prakash Raj

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  30.  
    31. not understanding the last formua..... pls explain
    6 years ago by ashmik harinkhede

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  31.  
    32. Sir, are we assuming that x is relatively small such that the sheet is infinite? If x is sufficiently large such that the sheet does not act as infinite, will the field still be uniform?
    6 years ago by Kishore Sathia

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  32.  
    33. Q- A molecule of a substance has a permanent electric dipole moment of magnitude 10–29 C m. A mole of this substance is polarised (at low temperature) by applying a strong electrostatic field of magnitude 106 V m–1. The direction of the field is suddenly changed by an angle of 60º. Estimate the heat released by the substance in aligning its dipoles along the new direction of the field. For simplicity, assume 100% polarisation of the sample. Please post the answer to this. As per my calculation Change in PE= Uf-Ui=3J. Thus there is a net increase in potential energy of the dipoles. Hence we should supply 3 J of energy as heat, for the material to align its dipoles. I don't think that the substance will release any heat, I think it should absorb 3J of heat from the surroundings.
    7 years ago by Smith

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  33.  
    34. I am not getting one thing. Yes I Got it m1v1=m2v2 by conservation of momentum. But. Thinking logically as both were released at rest at same time. Force acting on both due to each other is same [[ independent on mass..(kq1q2/r^2) ]]. Means acceleration is same. Means change in velocity should be same. So V1 = V2 ! Where did I commit a mistake. Please HELP !?
    7 years ago by Nachiketa Dev Sharma
    Ans 1 ->
    Force is same but masses are not same so acclerations are not same so change in velocities are are not same.
    7 years ago by I.Ajay Kumar Reddy

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  34.  
    35. how to sumit the questions
    8 years ago by Anshul Verma

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  35.  
    36. when we bring a unit positive charge from infinity to a point in the electric field EF does work on the charge and external work is also done on the charge in same amount but in opposite sign . then how energy is gained by the charge at the point . I mean if both works done on charge are equal and opposite how energy is gained by the charge?
    8 years ago by Aditya Rai
    Ans 1 ->
    energy of the system is increased ...
    7 years ago by Rohit mishra

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  36.  
    37. why the direction of dipole moment is from negative to positive?
    8 years ago by Guru Charan
    Ans 1 ->
    It is just a matter of Convention :-)
    7 years ago by Smith

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  37.  
    38. sir since the metal body is not uniformly charged how can you assign a uniform charge density of sigma
    8 years ago by Nimesh Dash

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  38.  
    39. why electric field inside an uncharged metal body is zero.
    8 years ago by venkatesh p

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  39.  
    40. can we consider a cylinder as an equipotential surface for a point charge . if not explain why electric field is not normal to all the points on the surface ?
    8 years ago by venkatesh p
    Ans 1 ->
    no electric field lines of a point charge are radial and not perpendicular to surface of cylinder draw this in a paper you will understand
    8 years ago by Ajay Sabarish

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  40.  
    41. why we take the limits from -L/2 to +L/2
    8 years ago by venkatesh p

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  41.  
    42. Explane why in the direction if electric field potential decreases
    8 years ago by Nitesh Guleria
    Ans 1 ->
    because dv/dr = -E you can see that if E is positive potential decreases with r.
    8 years ago by Ajay Sabarish

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  42.  
    43. Work ia a path function so it should depend upon path
    8 years ago by Nitesh Guleria
    Ans 1 ->
    but work done by conservative forces are path independent and electrostatic force is a conservative force
    8 years ago by Ajay Sabarish
    Ans 2 ->
    Work is a path function in case of first law of thermodynamics... here we are dealing with conservative electric field where it only depend upon initial and final positions...
    8 years ago by Physics Galaxy

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  43.  
    44. how CAN WE TAKE THE DISTANCE BETWEEN X AND Y COORDINATES AS 4. PLEASE EXPLAIN SIR.
    8 years ago by sagar choudhury

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  44.  
    45. why can't theta be 135
    8 years ago by Krishna Ramesh

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  45.  
    46. why charging cant be done by air friction as we say carge in indepenpent of velocity
    8 years ago by Aman Tiwari

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  46.  
    47. if suppose the bullet was at a very far distance from the sphere then u will become zero at certain point because due to repulsion its kinetic energy will keep on decreasing..is it not?
    8 years ago by payal singhal
    Ans 1 ->
    yes
    7 years ago by Vignesh Venkataraman

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  47.  
    48. it is said that at every point in the electric field..but we have to exclude the point at which the charge is placed..is it not?
    8 years ago by payal singhal

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  48.  
    49. can you please clearly explain why they will have same energy?
    8 years ago by payal singhal
    Ans 1 ->
    i mean to say same speed..sorry for wrong interpretation.
    8 years ago by payal singhal
    Ans 2 ->
    The three balls are initially placed at rest. Then all of them are under the effect of same amount of force ( KQ^2/R^2) We know that F=MA ! Since mass is also same. Accelereation effect is indeed same as well. Now you can't do momentum conservation because (Velocity being a vector) and we need to resolve it in directions and all. Thus energy conservation is used. Had masses been different so would be velocity.
    7 years ago by Nachiketa Dev Sharma

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  49.  
    50. in what case will they move with same velocity?
    8 years ago by payal singhal

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  50.  
    51. sir HOW WILL WE SOLVE IF POSITIVE CHARGES ARE NOT FIXED?
    8 years ago by UMANG GARG
    Ans 1 ->
    electrostatics means we are considering charges to be at rest..n moving charges produce current..so that will be completely a different frame..
    8 years ago by payal singhal

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  51.  
    52. A conducting liquid bubble of radius a and thickness t(t less less than a)is charged to potential V. If the bubble collapses to a droplet find the potential of the droplet.
    8 years ago by Parth Arora
    Ans 1 ->
    Assuming you are asking potential at the surface of drop....let charge provided to bubble be q....therefore k*q/(a+t) =V....here you may neglect t...from this find value of charge.. then use volume conservation. Since t is small volume of bubble = internal surface area *t.....4pi a^2 = 4/3pi*r^3...find r and input the value of r and q in the formula of potential due to solid sphere kq/2r^3 (3r^2-x^2)
    8 years ago by Mohak Sharma
    Ans 2 ->
    4pi a^2* t=4/3 pi r cube
    8 years ago by Mohak Sharma

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  52.  
    53. sir in Quset 1 Q.no 3 I think the option are incorrect
    8 years ago by Nishant Gaurav

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  53.  
    54. How To find the force between 2 dipoles when the are arranged in a random manner?? Please help me with this concept.
    8 years ago by Venkat S Raghavan

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  54.  
    55. how to find electric potential at a point when we are provided that electric potential at another point is zero
    8 years ago by kunal sevkani

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  55.  
    56. What if there is not any e-field then will there be any e-potential ?
    9 years ago by Vaibha Gupta
    Ans 1 ->
    If E=0 in a region then in that region V=constant and it may or may not be zero.. thats how we define equipotential region...
    9 years ago by Physics Galaxy
    Ans 2 ->
    If we consider a Hollow charged sphere,then Electric field inside the sphere=0, but potential is constant i.e. V=kQ/R
    8 years ago by Shivam Agarwal

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  56.  
    57. 9 years ago by Manik

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  57.  
    58. 9 years ago by Manik

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  58.  
    59. Sir why the expression for gravitational potential energy between the charged masses not written while conserving energy
    9 years ago by Mohak Sharma
    Ans 1 ->
    it is negligible compared to electrostatic potential energy
    8 years ago by Dhanush K

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  59.  
    60. if a hollow sphere with radius r1 and r2 is taken where r2 is greater than r1 the a +q charge is kept at centre the a pt c locate at a distance r from centre (r1 is smaller than r and r2 is greater than r) then potential at that pt c will be
    9 years ago by ameyayerpude
    Ans 1 ->
    You can find the electric field outside the sphere as q/(4*pi*eo*r^2) and inside the shell material as q/(4*pi*eo*er*r^2) and use integration (E.dr) from inf to r2 then from r2 to r to get the potential at point c.
    9 years ago by Physics Galaxy

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  60.  
    61. sir in this question have we neglected gravity ?
    9 years ago by vishal
    Ans 1 ->
    Yes as the acceleration due to electric field qE/m is much higher than g...
    9 years ago by Physics Galaxy
    Ans 2 ->
    how do we justify that qE/m is much higher than g?
    8 years ago by payal singhal
    Ans 3 ->
    just put the values of q ,E and m for any charged particle, you'll get it much more than 9.8 ms^2 take the values of m and q of an electron for example, and take E = 100 Vm^-1 or any other practical value
    8 years ago by ANURAG KAUSHIK
    Ans 4 ->
    WHy d/2 = 1/2 at^2 and not d/2 = ut + i/2 at^2
    8 years ago by venkatesh p
    Ans 5 ->
    d/2is not equal to ut 1/2at^2 because u is in the horizontal direction and not in the vertical direction
    5 years ago by Nipurn

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  61.  
    62. electric potential of uniformly charged hollow sphere
    9 years ago by Sara-Lynn Pelegrin
    Ans 1 ->
    For this please watch videos of section 'Electrostatics' under the topic 'Electric Potential' module - 31 to 33 in the tab 'PG Video Lectures'
    9 years ago by Physics Galaxy

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  62.  
    63. why cannot two equipotential surfaces cut each other..???
    9 years ago by rajat gupta
    Ans 1 ->
    because then there will be two directions of electric field at a single point which is not possible
    9 years ago by Aalind Sharma

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  63.  
    64. in one line had two points with zero potential on x axis
    9 years ago by devendra sain
    Ans 1 ->
    Yes if an equipotential surface cuts x axis at two or more points...
    9 years ago by Physics Galaxy

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  64.  
    65. What is The potential of earth?
    9 years ago by sambit kumar sahoo
    Ans 1 ->
    considered nearly zero and invariant for minor charge changes due to large size...
    9 years ago by Physics Galaxy

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  65.  
    66. according to defination of electric flux - it is just the number of electric line of forces through the given area . but electric flux has unit(Nm^2/C) why it is not unitless as flux is just number of lines ?
    9 years ago by Mohit Kuri
    Ans 1 ->
    Its a qualitative term when we talk in numbers... quantitatively its representing electric field by its density (per m^2) through a surface... Like power of a bulb represents more number of light rays but these cannot be counted and we can say as bulb power increases no of light rays of density of light rays emitted by bulb increase...
    9 years ago by Physics Galaxy

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  66.  
    67. if we mova a charged particle under electrostatic force . but initial potential is as the finsl potential. so the work done will be 0 or not.?
    9 years ago by abhinav singh
    Ans 1 ->
    zero...total work by elec forces...
    9 years ago by Physics Galaxy

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  67.  
    68. why dont we do root((x2-x1)^2 + (y2-y1)^2+(z2-z1)^2)=d.
    10 years ago by himanshu chhabra
    Ans 1 ->
    As potential difference is developed only due to electric field of which gradient gives the direction of E vector...
    9 years ago by Physics Galaxy

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  68.  
    69. why dx is taken negative?
    10 years ago by yogeshwaran
    Ans 1 ->
    As we are decreasing x from inf to r...
    9 years ago by Physics Galaxy

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