A current-carrying circular loop lies on a smooth horizontal plane. A) Can a uniform magnetic field be set up in such a manner that the loop turns around itself (i.e., turns about the vertical axis).

(b) A current-carrying circular loop is located in a uniform external magnetic field. If the loop is free to turn, what is its orientation of stable equilibrium? Show that in this orientation, the flux of the total field (external field + field produced by the loop) is maximum.

(c) A loop of irregular shape carrying current is located in an external magnetic field. If the wire is flexible, why does it change to a circular shape?      

Asked by manishjs222 | 5th May, 2020, 03:52: PM

Expert Answer:

The torque responsible for turning the loop is given by
M with rightwards arrow on top cross times B with rightwards arrow on top
T h e space D i r e c t i o n space o f space M with rightwards arrow on top space f o r space h o r i z o n t a l space l o o p space i s space p e r p e n d i c u l a r space t o space t h e space p l a n e space o f space t h e space l o o p
S O space i f space a n y space f i e d space B space i s space a a p p l i e d space i n space t h e space h o r i z o n t a l space d i r e c t i o n space i t space w i l l space n o t space g e n e r a t e space t h e space f o r c e space tan g e n t i a l l y space t h a t
c a n space m a k e space t h e space l o o p space r o t a t e space a b o u t space i t s space v e r t i c a l space a x i s
I f space t h e space f i e l d space B with rightwards arrow on top space i s space a p p l i e d space i n space t h e space v e r t i c a l space d i r e c t i o n space t h e n
i t space m a k e s space a n g l e space 0 to the power of 0 space w i t h space t h e space M with rightwards arrow on top space a n d space h e n c e space t h e space t o r q u e space i s space z e r o.
H e n c e space i t s space n o t space p o s s i b l e space t o space r o t a t e space t h e space l o o p space a l o n g space i t s space a x i s

Answered by Utkarsh Lokhande | 5th May, 2020, 11:54: PM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.