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

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  1.  
    2. j
    2 years ago by Gautam Kapoor

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  2.  
    3. Sir I have not understood the direction of current and magnetic field?
    2 years ago by Nihaal Tapasi

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  3.  
    4. sir the value pf Bfg have give length from wire as "a" but it is actually "a/2^0.5".
    3 years ago by

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  4.  
    5. sir how do we remember all the formulas ?
    4 years ago by Srusti R

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  5.  
    6. sir how the direction of magnetic induction of (FG) wire is along i^ or + x axis
    4 years ago by Satish

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  6.  
    7. thanks for teaching sir
    4 years ago by Satish

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  7.  
    8. sir what is drift velocity
    4 years ago by Priya Khradia

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  8.  
    9. sir in this vdo how u write second step of dB vector = u° /4p{I dl sin theta / r². } sir plzz reply sir ????????
    4 years ago by Priya Khradia

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  9.  
    10. can u explain the enclosed current equation sir
    4 years ago by satya

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  10.  
    11. sin theta add hoke 2 sin theta kyu nahi ban raha
    4 years ago by

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  11.  
    12. sir in this y is equal to r /tan theta ….u have take theta at diff pt
    4 years ago by

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  12.  
    13. Audio is not working.
    4 years ago by Nihal H

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  13.  
    14. sir pls upload exercises soln
    4 years ago by

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  14.  
    15. SIR IN THIS LECTURE HOW YOU WRITE THE INTEGRATION OF DL AS 2PIR^2 PLEASE TELL ME FASTLY
    5 years ago by Avinash Pandey

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  15.  
    16. For JEE Main 2020 January, is it necessary to remember derivations from Ampere's Law if I already know the how to find Magnetic Induction by Biot Savarts Law?
    5 years ago by

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  16.  
    17. why we didn't used semi infinite formula
    5 years ago by Satyam kumar

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  17.  
    18. how to prove by biot savart law
    6 years ago by Sarju Panchal

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  18.  
    19. Sir, please please explain how the angle came out to be 30? I have been trying since the past4 hours
    6 years ago by S James

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  19.  
    20. how magnetic induction is 0 inside
    6 years ago by Harshit Singh

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  20.  
    21. how is magnetic induction circular in this it should be inside the plane of paper by RHTH?
    6 years ago by Harshit Singh

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  21.  
    22. how is magnetic induction circular in this it should be inside the plane of paper by RHTH?
    6 years ago by Harshit Singh

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  22.  
    23. how is magnetic induction circular in this it should be inside the plane of paper by RHTH?
    6 years ago by Harshit Singh

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  23.  
    24. how is magnetic induction circular in this it should be inside the plane of paper by RHTH?
    6 years ago by Harshit Singh

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  24.  
    25. how is magnetic induction circular in this it should be inside the plane of paper by RHTH?
    6 years ago by Harshit Singh

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  25.  
    26. how is magnetic induction circular in this it should be inside the plane of paper by RHTH?
    6 years ago by Harshit Singh

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  26.  
    27. sir why we have not used the formula of semi infinite wire
    6 years ago by undefined

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  27.  
    28. sir, we can extend the side CD of the loop to any place inside the crossection of solenoid and we will get the same value for induced magnetic field B, is this the reason why all the interior points inside the solenoid have uniform B?
    6 years ago by Abhishek Mania

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  28.  
    29. sir, while integrating the angles should we always integrate from a negative angle to a positive angle?
    6 years ago by Abhishek Mania

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  29.  
    30. sir how is the perpendicular distance r sin 30 degree.
    6 years ago by ranbir singh

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  30.  
    31. I am just curious to know about why ammeter deflection opposite to the flow of current?
    6 years ago by Hate Nation

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  31.  
    32. Sir, shouldn't r = y.tan ?? In the above video, you wrote y = r.tan ?
    6 years ago by Ivan Koshy

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  32.  
    33. Sir, how to calculate variation of magnetic field inside a solenoid with distance from central Axis.
    7 years ago by suneet kumar

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  33.  
    34. what is lenzs law iam not understanding it
    7 years ago by qamar hussain malik

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  34.  
    35. sir how cam you use right hand thumb rule to find direction of magnetic field in this case?
    7 years ago by Dharamjeet Singh

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  35.  
    36. can we take b1 and b2 either any one of the 2 ?
    7 years ago by Dharamjeet Singh
    Ans 1 ->
    wire which is closer will have higher B
    6 years ago by Hate Nation
    Ans 2 ->
    and yes u can take but subtract the b finite length wire with another since it is closer to O
    6 years ago by Hate Nation
    Ans 3 ->
    sir how is the perpendicular distance r sin 30 degree.
    6 years ago by ranbir singh

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  36.  
    37. As also asked by Manish Tiwari, why is x = R * tan(theta)? There is no angle called theta
    7 years ago by Best Bunny EU

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  37.  
    38. How is the direction for B(AB) =-k?
    7 years ago by Yukti Khosla
    Ans 1 ->
    curl your fingers along the direction of the arrow that is the current with your right hand... the direction of you thumb will point inside the screen which is -k
    7 years ago by ABHISHEK SHANKAR

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  38.  
    39. Sir why we haven't used sin result
    7 years ago by Anshuman
    Ans 1 ->
    you can use the sine result also.... but you will have to use sin 60 which will the same answer
    7 years ago by ABHISHEK SHANKAR

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  39.  
    40. Sir why we haven't used sin result
    7 years ago by Anshuman

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  40.  
    41. Here , angle phi is in radian..?
    7 years ago by Amit Vikram Raj

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  41.  
    42. Sir, why you have taken here , dx × (r/cosx) = dl cosx
    7 years ago by Amit Vikram Raj
    Ans 1 ->
    because dl cosx is the arc length... according to the derivation the arc length is Ro cos x which is R/cosx dx
    7 years ago by ABHISHEK SHANKAR
    Ans 2 ->
    sorry Ro dx is the arc length which is R/cosx dx
    7 years ago by ABHISHEK SHANKAR

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  42.  
    43. Sir, if I take y=r cot(theta) , What is wrong in taking this?
    7 years ago by Amit Vikram Raj
    Ans 1 ->
    well then you will get UoI/4piR * integration of ln(cossecQ cot Q) limits from 0 to pi... probably going to yield the same answer in a more complicated way
    7 years ago by ABHISHEK SHANKAR

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  43.  
    44. Sir, can we define a magnetic moment for a current carrying circular ring and using that we can find magnetic induction B for any point on the space surrounding the ring?
    7 years ago by Srivatsan R

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  44.  
    45. sir can we find it by using previous method
    7 years ago by rameh hooyex

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  45.  
    46. sir how u come 2 knw that this particular substitution is required ???
    7 years ago by rameh hooyex
    Ans 1 ->
    well you can see the expressions differentiation lies in the numerator like of the form f '(x) / f(x) and plus it is in the form of 1/x^2 a^2... you might have studied in integration that in such cases you first substitute x as AtanQ and see the expression that to yields... it is like a hit and trial method which in most cases is successful
    7 years ago by ABHISHEK SHANKAR

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  46.  
    47. Sir what is velocity selector
    8 years ago by Chaitanya

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  47.  
    48. hlo sir.in this question two semi infinite wire has been used.but you have solve this problem by using finite length of wire.why?
    8 years ago by Nikunj kumar Shaunak

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  48.  
    49. hlo sir.in this question two semi infinite wire has been used.but you have solve this problem by using finite length of wire.why?
    8 years ago by Nikunj kumar Shaunak

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  49.  
    50. hlo sir.in this question two semi infinite wire has been used.but you have solve this problem by using finite length of wire.why?
    8 years ago by Nikunj kumar Shaunak
    Ans 1 ->
    watch it carefully we have used the result but used angles for semi infinite wire only...
    8 years ago by Physics Galaxy

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  50.  
    51. but then we integrate with respect to angle i get sinO1+SinO2
    8 years ago by Anmol Khurana
    Ans 1 ->
    You can watch the video again carefully... integration can be carried out wrt any reference and limits are also taken accordingly...
    8 years ago by Physics Galaxy

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  51.  
    52. Why is field outside solenoid 0
    8 years ago by Divya r
    Ans 1 ->
    Because all upper half and lower half parts of solenoid will nullify the magnetic field outside in all directions...
    8 years ago by Physics Galaxy

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  52.  
    53. Sir how is current n×e×a×dl
    8 years ago by Divya r
    Ans 1 ->
    Here current is nxexAxv not dl... watch again...
    8 years ago by Physics Galaxy

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  53.  
    54. And sir can we know what plane just by looking the figure?
    8 years ago by Avinav Sharma
    Ans 1 ->
    The planes are mentioned in the figure and you can orient your hand fingers and palm in front of the figure... with practice only you can gain command over it...
    8 years ago by Physics Galaxy
    Ans 2 ->
    Hold a pen or something and imagine current passing through you looking towards the wire while holding the pen imagine the coordinates surrounding you, since you are living in 3-D questions of 3-d will be easier to imagine
    6 years ago by Hate Nation

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  54.  
    55. Sir I could not get the directions ...
    8 years ago by Avinav Sharma
    Ans 1 ->
    As I mentioned in the answer to your reply above you need to do lot of practice on such questions for three dimensional orientations to understand the same...
    8 years ago by Physics Galaxy

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  55.  
    56. Sir in correction to my earlier question shouldn't the angle be 60 degrees?
    8 years ago by Avinav Sharma
    Ans 1 ->
    See the figure again carefully... the analysis done is correct...
    8 years ago by Physics Galaxy

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  56.  
    57. Sir shouldn't the angle be 3o degrees?
    8 years ago by Avinav Sharma
    Ans 1 ->
    See the figure again carefully... the analysis done is correct...
    8 years ago by Physics Galaxy

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  57.  
    58. why can't we apply ampere circuital law to this problem
    8 years ago by ariya
    Ans 1 ->
    It can be applied by considering elemental wire in strip and integrating the result... as a whole on strip it cannot be applied directly as there is no symmetrical amperes path can be selected in this situation...
    8 years ago by Physics Galaxy
    Ans 2 ->
    It can be applied by considering elemental wire in strip and integrating the result... as a whole on strip it cannot be applied directly as there is no symmetrical amperes path can be selected in this situation...
    8 years ago by Physics Galaxy

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  58.  
    59. sir i am confusing with the directions of m.field please clear .i am unable to apply right hand thumb rule correctly so sir plz help me so that i shall be thankful to you with regard likith.b
    8 years ago by b.likith sudhakar
    Ans 1 ->
    Try this - To find the direction of Magnetic Field put your right hand thumb along the direction of current and spread your right hand palm straight toward the point where you want to get the field direction... in this state your palm face give you the direction of magnetic field...
    8 years ago by Physics Galaxy
    Ans 2 ->
    To find magnetic field direction use a different method... place your right hand thumb along direction of current and stretch your right hand palm toward the point where you want to find the direction of magnetic field, in this state your right hand palm face will point toward the direction of magnetic field at that point...
    8 years ago by Physics Galaxy

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  59.  
    60. why is eddy current not formed in a straight conductor while ed factor is present in the caese of an inductor
    8 years ago by vishnuv
    Ans 1 ->
    If conductor has thickness then in its body volume eddy currents will be induced...
    8 years ago by Physics Galaxy

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  60.  
    61. sir why we taking dl(cross)r why not I(cross)r? i am waiting for your reply
    8 years ago by ariya
    Ans 1 ->
    current is scaler so its cross product cannot be taken...
    8 years ago by Physics Galaxy

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  61.  
    62. let y=rtan0 but sir i hope that it is y=r/tan0 by diagram shown
    8 years ago by Devendra singh
    Ans 1 ->
    Here I have taken y=r tanT as a trigonometric substitution not the relation from the figure... consider this separately...
    8 years ago by Physics Galaxy

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  62.  
    63. Sir how you determined the signs of current
    8 years ago by Kunal Mohapatra
    Ans 1 ->
    These have to be taken in opposite direction so result will remain same even if you change the directions...
    8 years ago by Physics Galaxy
    Ans 2 ->
    try to understandfrom yourself
    8 years ago by kshitiz

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  63.  
    64. Sir can you explain again how the direction of dB was determined
    8 years ago by Kunal Mohapatra
    Ans 1 ->
    This is by Right hand thumb rule... however on paper it is by consideration of current flow as per the diretion of current we have taken...
    8 years ago by Physics Galaxy

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  64.  
    65. How the direction of magnetic field induction is in negative Y axis it should be along negative Z axis
    8 years ago by Kunal Mohapatra
    Ans 1 ->
    Due to the third semi infinte wire... if you place your thumb along the direction of current then your fingers will point along -Y direction... watch it carefully again...
    8 years ago by Physics Galaxy

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  65.  
    66. Why aren't your books on these chapters available?
    8 years ago by Rahul Thorat
    Ans 1 ->
    Physics Galaxy on Electromagnetism will be available by end of December 2017...
    8 years ago by Physics Galaxy

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  66.  
    67. how to find the direction of dB
    8 years ago by sundeep
    Ans 1 ->
    Use right hand thumb rule for the element...
    8 years ago by Physics Galaxy

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  67.  
    68. sir , similar to electric field magnetic field too are perpendicular to the surface from which they originate ..... what is the reason for this???
    9 years ago by Varun V

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  68.  
    69. Why is ampere law not valid on finite wire?
    9 years ago by Rahul Misra
    Ans 1 ->
    It is valid on all type of wires but in Ampere's Law magnetic field in the line integral is the total magnetic field of all the wires in space and in finite wire we ignore the terminal connections so it cannot give the field only due to finite wire...
    9 years ago by Physics Galaxy

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  69.  
    70. Do I need to solve numericals from magnetism and matter for IITJEE?
    9 years ago by Bhaskar Gope

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  70.  
    71. Sir are all the question in the practice assignment have right answers?
    9 years ago by Kanwal Deep

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  71.  
    72. How does magnetic properties work in an atom according to quantum model? i mean, we are taught about the magnetic property by bohr's model which assumes that electron revolves around the nucleus in a circular path. But in reality it doesn't do so. So, how does magnetic properties work in an atom according to quantum model?
    9 years ago by Prateek Kumawat

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  72.  
    73. Sir We integrated 'dl'for whole path (2pi r) so magnetic field thus derived should be same for every point on that path ?
    9 years ago by Vaibhav Gupta

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  73.  
    74. Sir We integrated 'dl'for whole path (2pi r)
    9 years ago by Vaibhav Gupta

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  74.  
    75. WHY we have taken x= Rtan0 ???here where there is no 0.
    9 years ago by Manish Tiwari
    Ans 1 ->
    This we are doing for integration by substitution... hope you have covered integration by substitution...
    8 years ago by Physics Galaxy

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  75.  
    76. Is the I1/I2 part correct...if so you explain it better?
    9 years ago by Josh Pius

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  76.  
    77. in magnetic field due to straight current carrying conductor if the point is taken on the conductor itself R=0 then B should be infinity but y it is 0
    10 years ago by Karthikesh
    Ans 1 ->
    Analytically - If you use ampere's law the in a loop of zero radius no current is enclosed so B=0 and Qualitatively - at the center of wire magnetic induction due to outer symmetric current will all get cancelled so it is zero... The expression of magnetic induction inside a wire is given in Module-28 of the topic 'Magnetic Effect of current' under the section 'Magnetic Effects'... Pl watch this module video to understand that B is directly proportional to r inside the wire so at r=0, B=0...
    10 years ago by Physics Galaxy

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  77.  
    78. sir , please check the calculation once..(r=ytan(teta) )
    10 years ago by ab vishal
    Ans 1 ->
    All calculations in this video are correct... theta which I have used in first step of sin(theta) is the one which is shown in figure and the theta which I have used for integration is just a substitution... you can see that further I am using at y = inf, theta will become pi/2 and theta in figure will approach to zero... I think now you have got it...
    10 years ago by Physics Galaxy

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  78.  
    79. CAN WE APPLY AMPERE'S LAW ON A 1m LONG WIRE?WHY OR WHY NOT?
    10 years ago by VIJIT KANJILAL
    Ans 1 ->
    Ampere's law can be applied on any wire but the calculation of line integral may not be carried out so easily which we can do in case of an infinite wire... because in line integral B is the net magnetic induction due to all currents in surrounding and we don't have information about other conductors through which current is flowing in this 1m wire...
    10 years ago by Physics Galaxy

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  79.  
    80. CAN WE APPLY AMPERE'S LAW ON A 1m LONG WIRE?WHY OR WHY NOT?
    10 years ago by VIJIT KANJILAL
    Ans 1 ->
    Yes it can be applied as ampere's law is always applicable but in this case we will not be able to solve the equation as we are not provided the information about the connecting wires through which current is supplied in this 1m long wire and in AL we need to use the net B(vec) in equation.... I hope you have not got it...
    10 years ago by Physics Galaxy

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  80.  
    81. sir, when a charged particle is accelerated ... is it true that the field then created is only magnetic , or it also has a electric field around it or in any other direction
    10 years ago by yashwanth
    Ans 1 ->
    electric fields do exist
    10 years ago by Ch Vishal
    Ans 2 ->
    it has both electric and magnetic field
    10 years ago by Divyanshu Gupta
    Ans 3 ->
    It depends up on the observer
    10 years ago by Karthikesh
    Ans 4 ->
    as i read it somewhere .. magnetic field is electric field in another frame of reference .
    10 years ago by yashwanth

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  81.  
    82. Hello Sir, The formula should be Half of Bp. Then only it wil come 4pi r. Please check it again!!!
    10 years ago by Dr.Madhu Sharma
    Ans 1 ->
    Here Bp is the magnetic induction due to semi inf wire and B is that of complete wire so Bp will be half of B...
    10 years ago by Physics Galaxy

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  82.  
    83. Hello Sir, Please check the tan theta formula again because r/y = tan theta then how come y = r tan theta??? Please check it again sir.....
    10 years ago by Dr.Madhu Sharma
    Ans 1 ->
    In this analysis I am using y = r tan (theta) as trig substitution for integration it is not related to the diagram... pl check it carefully... its correct...
    10 years ago by Physics Galaxy

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  83.  
    84. sir, i have an objection. Shoudn't magnetic field in xy region be in anticlockwise dirn like in ab region.
    10 years ago by himanshu chhabra
    Ans 1 ->
    If you look at the figure from left side it will clokclockwise as I have drawn and if look at it from right side...it will be anticlockwise...
    10 years ago by Physics Galaxy

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  84.  
    85. two long parallel wires are at a distance 2d apart.they carry steady equal currents flowing out of the paper.the variation of magnetic field b along the line joining them is given by :
    11 years ago by kilari karthik
    Ans 1 ->
    approaching to inf close to wires and minimum at midway...
    10 years ago by Physics Galaxy

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