1. Please write clearly, thank you..
35. Two long, straight wires carry equal currents as shown, in the plane of the page. What is the
direction of magnetic field at point P? a) +x b) -x c) +y d) +z e) -z
36. Two long, straight, parallel current-carrying wires lie in the plane of the page. Current flows
in the direction indicated. What is the direction of magnetic force on wire 2, from wire 1? a) +x
b) -x c) +y d) +z e) -z
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28. Two long, straight wires in the plane of the page carry equal currents as shown. What is the
direction of magnetic field at point P? a) +x b) +y c) +z d) -x e) -y
29. Two long, straight, parallel wires carry currents in opposite directions as shown. What is the
direction of magnetic force acting on the left wire? a) +y b) -y c) +x d) -x e) more info is needed
to determine
35. Two long, straight wires carry equal currents as shown, in the plane of the page. What is the
direction of magnetic field at point P? a) +x b)-? ty +z e) -Z 36. Two long, straight, parallel
current-carrying wires lie in the plane of the page. Current flows in the direction dicated. What is
the direction of magnetic force on wire 2, from wire 1? -X c) ty d) +z e) -z
Solution
35)
Using right hand thumb rule, direction of magnetic field due to wire 1 (carrying current up) is
into the page.
Due to wire 2 (carrying current towards right) is out of the page.
Now, wire 2 is close to the point P, so its field will dominate over 1. Hence, net direction would
be out of the page, or +z.
36)

2. Opposite currents repel each other. So, force on wire 2 would be towards right (repelling force
on it).
Hence, the direction is towards +x.
28)
As in first solution, the wire carrying carrying downward current is close to the point, so its field
will dominate. By right hand thumb rule, the direction would be outward, or +z.
29)
Opposite currents repel each other.
So, magnetic force on left wire would be towards left (repelled direction). Or, -x.