Share Questions which are "not Hard but require Deep Thinking"

[Satyendra_Srivastva]

Is my figure correct?

[pratyaksh_tyagi]

Yes , now place the smaller loop inside it

[Satyendra_Srivastva]

OK uske baad bro I stuck here @pratyaksh_tyagi

[pratyaksh_tyagi]

This is what I thought:
First find torque as a function of theta , for both then use Tau= Ialpha , and find theta as function of time , and then we can find the relation between their respective angle of rotation for same time t, and then find potential energy using M•B as a function of theta ( for smaller loop )which is being used as Rotational ke, and maximise it
Very tough and tiring
@Viraj don't tell the answer until I tell

[Satyendra_Srivastva]

At least @Viraj plz tell is this approach(pratyaksh tyagi's) is correct.
Also why @pratyaksh_tyagi You think that question is about maximum rotational kinetic energy

[pratyaksh_tyagi]

I said maximise potential energy of the magnetic dipole ( loop) which is -M•B

[Satyendra_Srivastva]

-\vec M_1•\vec B_2= - i_1(\vec A_1•\vec B_2)
Bro initially their area vectors and Magnetic field vector is perpendicular so at that time they have 0 potential energy Na.

[pratyaksh_tyagi]

Yes

[Satyendra_Srivastva]

According to my method if one is rotate clockwise then other is rotate anticlockwise.
Also r<<R so at the common centre B_2>>B_1

[pratyaksh_tyagi]

That depends on direction of current

[Satyendra_Srivastva]

OK Now we have to find a way to connect these to get Max KE
PE+KE= constant na

[pratyaksh_tyagi]

No , the forces are not conservative

[Viraj]

Ok, not telling the answer @pratyaksh_tyagi

@Satyendra_Srivastva We need to make 2 equations (one conserving energy and one conserving angular momentum)

@Sourav_Madanpuri r<<<R is given so that while writing energy equation we can neglect PE of larger disc in comparison to smaller one and also we can write P.E of smllaer disc directly using B at centre of larger disc..

[pratyaksh_tyagi]

But how angular momentum is conserved ?
Net external torque is not 0

[Viraj]

acc. to u from where is net extrnal torque coming??

There is No net external torque

[Viraj]

Perfect. @Satyendra_Srivastva Kudos.

[Satyendra_Srivastva]

I should delete it so that others enjoy it more thanks for verify

[Viraj]

Ur wish...Wc.

U did by the same method or anything else? @Satyendra_Srivastva

Ohok. Fine. @Satyendra_Srivastva

[pratyaksh_tyagi]

The torque M*B , anyways I'm not doing this anymore

[Satyendra_Srivastva]

Bro where you didn't understand tell me I would help you