Three identical coils 
and 
are closely placed such that they share a common axis. 
is exactly midway. 
carries current 
in anti-clockwise direction while 
carries current 
in clockwise direction. An induced current flows through 
will be in clockwise direction when
moves away from 
and 
moves towards 
and 
move with equal speeds away from 
moves towards 
and 
moves away from 
and 
move with equal speeds towards 
Text Solution
Verified by ExpertsC
Let the common axis be the z -axis.
is at 
is at 
, and 
is at 
.
Current in 
is anti-clockwise (ACW), producing a magnetic field 
in the 
direction at 
.
Current in 
is clockwise (CW), producing a magnetic field 
in the 
direction at 
.
The net magnetic field at 
is 
. Since 
and 
are equidistant and carry equal current, initially 
.
To induce a clockwise current in 
, Lenz's law states that the induced current must oppose the change in flux. A clockwise induced current produces a magnetic field in the 
direction.
This happens if there is an increasing flux in the 
direction or a decreasing flux in the 
direction.
Case 1: 
moves towards 
. The distance decreases, so 
(in 
direction) increases. This causes an increasing flux in the 
direction.
Case 2: 
moves away from 
. The distance increases, so 
(in 
direction) decreases. This causes a decreasing flux in the 
direction.
Both actions (moving 
towards 
and moving 
away from 
) result in a net change in flux that induces a clockwise current in 
to oppose the change.
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