28. Advance Illustration | Magnetic Effects & EMI | A Suspended Rotating Ring | by Ashish Arora

The website, aimed at nurturing grasping power students, has classroom lectures on almost all the topics. It is an outcome of 23-year long toil of Physics expert who has made it a mission to simplify the complexities of Physics.

Ashish Arora, the brain behind this interactive unique website, has all his lectures available on web for free of cost. He has created a youtube channel in the name of Physics Galaxy. Today more than 6000 video lectures are being watched per day on this website which is highest among any other e-learning website in India. Till now more than 3.6 Million videos are watched on it. On each video subtitles are also available in 67 languages using google translator including English, Hindi, Chinese, French, Marathi, Bangla, Urdu and other regional and international languages.

Besides uploading transcripts of all his videos, he has created a software based synchronized European voice accent of all videos to benefit students in USA, Europe and other countries.

#AshishArora #JEEAdvanced #JEE2020

[ArthBachhuka]

Those who are confused, from M×B we get the -z axis as the axis of ratation and now if we pount the thumb towards the -z axis and curl the fingers it shows the direction of torque which is in clockwise sense, now its just net torqu of all forces =0

[radhamay]

for those who are wondering...how torque about c is taken this way....becoz magnetic torque is actually couple and that is independent of axis of rotation.

[devainpalbansal]

Sir, the ring is rotating anticlockwise (viewed from C) so M is towards C that means MxB is coming out plane, so string 1 should break acc. to the assumption we have taken.

[himanshuverma]

previous year great question thank you for the solution sir

[TargetIITBatch]

The People who are confused about the torq by ring should derive the torq by ring in this case by elemental method means just from the basics by taking the element dx on the ring and writing the torq by that dx element for the point c ....
will get the same answer i have done it its not a big deal to do that all u need is just confidence that u are doing it right while doing this mehtod ....dont memorise :)

[shashikantmaurya]

Couple torque is independent of position..

[lakshaybansal]

Respected sir initially angular momentum arrow of rotating disc was in -ve x direction (towards c) where a torque in direction of -ve z (into the plane) was applied due to which the new angular momentum vector should point in the direction of vectorial addition of initial angular momentum and torque giving wheel an acw spin so acc to me point c should go below the plane and d above the plane and the net tension should be same in both strings where am i going wrong??

[vishwasjajpura]

Sir, I did not get
how did you check direction of torque of B wrt to mg and tension

[ishaanagarwal]

When writing the equilibrium of the rod, why have we written the torque experienced by the ring. How does the torque experienced by the ring get transferred to the whole system?

[jagdishkumar]

as magnetic field is uniform and charged ring is initially at rest, it means uniform magnetic field can rotate ring, sir how it is possible because only time varying magnetic field can rotates

[ankitjaiswal]

sir why haven't we balanced the torque about centre of the ring instead of balancing at the edge of the rod, sir plz tell

[dilkhushalam]

Sir u have written same direction for magnetic and gravitational torque. How this happened. Please help me

[GOROSEIMAGREGOR]

I got same ans but with different sign as calculated about point D.

[amantripathi]

sir how you have find the direction of torque

[tanuchugh]

sir why the torque of ring about its center and about c is same ?

[tushargupta]

here if we put max tension as T(not) then aren't we maximising the omega as omega is directly proportional to tension

[ashutoshpati]

Sir here length of rod is not given in question how it be in the answer 😕🤔

[AmanMishra-dbde]

Sir ...as the torque on ring we have calculated is about COM of ring ....how is it same about point C ...as torque is always defined about a point ??? Sir plzzz help ..??

[_callmegupta]

I do challenging questions of physics whenever i feel low to lift my mood up!!!