7. A wire carries a steady current of 5A. A straight section of the wire is 30 cm long and lies along the x axis within a uniform magnetic field, B = 3 mT in negative x-direction. If the current is in the positive x direction, what is the magnitude of the magnetic force acting on this section of wire?
(A) 10 N
(B) 100 N
(C) 9.3×10⁻⁴ N
(D) 0 N
8. Determine the initial direction of the deflection of the negatively charged particle as it enters the magnetic fields as shown in figure.
(A) up
(B) out of the page.
(C) into the page.
(D) no deflection.
9. A wire carries current in the plane of this paper toward the bottom of the page. The wire experiences a magnetic force toward the right edge of the page. What is the direction of the magnetic field causing this force?
(A) In the plane of the page and toward the left edge.
(B) In the plane of the page and toward the right edge.
(C) Upward
(D) Downward