A proton is fired horizontally into a 1.0×10⁵ N/C vertical electric field. It rises 1.0 cm vertically after having traveled 5.0 cm horizontally. What was the proton's initial speed?

FIGURE EX23.25 shows a $1.5$ g ball hanging from a string inside a parallel-plate capacitor made with 12 cm × 12 cm electrodes. The electrodes are charged to±75 nC. What is the charge on the ball in nC?

Electrostatic cleaners remove small dust particles and pollen grains from air by first ionizing them, then flowing the air between the plates of a parallel-plate capacitor, parallel to the plates, where electric forces deposit charged particles on one of the electrodes. A typical pollen grain has a mass of $5.0\times {10}^{-10}$ g, the ionizer charges it with $750$ extra electrons, and a fan moves the air at $3.0$ m/s. Ignore air resistance and gravity. What minimum electric field strength is needed to deflect the grain by $3.0$ mm before it leaves the electrodes?

What are the strength and direction of the electric field at the position indicated by the dot in FIGURE P23.37? Give your answer (a) in component form and (b) as a magnitude and angle measured cw or ccw (specify which) from the positive x-axis.

Two 2.0-cm-diameter disks face each other, 1.0 mm apart. They are charged to ±10 nC. A proton is shot from the negative disk toward the positive disk. What launch speed must the proton have to just barely reach the positive disk?

INT The surface charge density on an infinite charged plane is −2.0×10⁻⁶ C/m². A proton is shot straight away from the plane at 2.0×10⁶ m/s. How far does the proton travel before reaching its turning point?

The permanent electric dipole moment of the water molecule (H₂O) is $6.2\times {10}^{-30}$ Cm. What is the maximum possible torque on a water molecule in a $5.0\times {10}^8$ N/C electric field?