8 Figure 29-31 shows four arrangements in which long, parallel, equally spaced wires carry equal currents directly into or out of the page. Rank the arrangements according to the magnitude of the net force on the central wire due to the currents in the other wires, greatest first. (a) (b) (c) (d)

9. Two differential current elements, I₁AL₁= 3×10° ay Am at P₁(1,0, 0) and 1₂AL2= 3×10 (-3a +4ay+5a) A⋅m at P₂(2, 2, 2), are located in free space. Find the vector force exerted on 12AL2 by I₁AL₁.

(a) The figure below shows two parallel conducting rails 15.2 cm apart, connected by a resistor with resistance R₂ = 5.00 Q. Two metal rods with resistances R₁ = 11.40 and R₂ = 15.0 (2 slide along the rails with negligible friction. Rod R₁ slides to the left at constant speed v₁ = 4.00 m/s, while rod R₂ slides at speed v₂ = 2.00 m/s. The rods and rails are in the presence of a uniform magnetic field pointing into the page, perpendicular to the plane of the rails, with a magnitude of Bin = 0.0100 T. +5 x x x x x x x x x x x x x x x x x x x x x x x x x x upward x x x ---Select--- X * x x x x x x x x Rg x x x x x R₁ R₂ What are the magnitude (in μA) and direction of the current through resistor R₂? μA magnitude direction x x x x (b) What If? What are the magnitude (in μA) and direction of the current through resistor R. if the rods move inward, instead of outward, with the same speeds as in part (a)? μA magnitude direction

An accelerating voltage of 2.36 x 10³ V is applied to an electron gun, producing a beam of electrons originally traveling horizontally north in vacuum toward the center of a viewing screen 37.9 cm away. (a) What is the magnitude of the deflection on the screen caused by the Earth's gravitational field? (b) What is the direction of the deflection on the screen caused by the Earth's gravitational field? up down east west (c) What is the magnitude of the deflection on the screen caused by the vertical component of the Earth's magnetic field, taken as 20.0 μT down? east m (d) What is the direction of the deflection on the screen caused by the vertical component of the Earth's magnetic field, taken as 20.0 µT down? north south west mm (e) Does an electron in this vertical magnetic field move as a projectile, with constant vector acceleration perpendicular to a constant northward component of velocity? Yes No O No (f) Is it a good approximation to assume it has this projectile motion? Yes…