Jen is conducting an experiment involving a device known as a pith-ball electroscope, shown below. The plastic ball of the electroscope hangs in midair and is uncharged. Charges cannot move along the silk thread that holds the ball in the air.

Jen completes the following steps in her experiment:
She collects three identical, uncharged rubber tubes.
She holds a magnet to the first tube for 5 minutes.
She submerges the second tube in a tank of water for 5 minutes.
She rubs the third tube with animal fur for 5 minutes.
Jen's teacher tells her that she can use the pith-ball electroscope to see if any of the rubber tubes are surrounded by an electric field. What should Jen do to test for an electric field surrounding each tube?
A.
connect the three tubes to each other and see if they attract the plastic ball
B.
bring the magnet close to the plastic ball and note any motion of the ball toward the magnet
C.
hold the magnet in direct contact with the tube that was submerged in water
D.
bring each tube close to the plastic ball and note any movement of the ball

To create electromagnetic induction, which of the following has to move? a. a wire b. a magnet c. a transformer d. either a or b

Agas is contained in a vertical, frictionless piston–cylinder device. the piston has a mass of 3.2 kg and a cross-sectional area of 35 cm2. a compressed spring above the piston exerts a force of 190 n on the piston. if the atmospheric pressure is 95 kpa, determine the pressure inside the cylinder.

Dinate system, and a charge q = - 2.00 nc is placed s2 10 n> c. (a) what is the change in electric potential energy when the dipole moment of a molecule changes its orientation with respect to es from parallel to perpendicular? (b) at what absolute temperature t is the average translational kinetic energy 32 kt of a molecule equal to the change in potential energy calculated in part(: abovethistemperature, thermalagitationprevents the dipoles from aligning with the electric field.) placed in a uniform electric field e with magnitude 1.6 * 6 on the positive x-axis at x = 4.00 cm. (a) if a third charge q3 = +6.00 nc is now placed at the point x = 4.00 cm, y = 3.00 cm, find the x- and y-components of the total force exerted on this charge by the other two. (b) find the magnitude and direction of figure p21.62 ll uu 21.55 . torque on a dipole. an electric dipole with dipole moment ps is in a uniform external electric field es. (a) find the orientations of the dipole for which the torque on the dipole is zero. (b) which of the orientations in part (a) is stable, and which is unstable? (hint: consider a small rotation away from the equi- librium position and see what happens.) (c) show that for the stable orientation in part (b), the dipole’s own electric field tends to oppose the external field. 21.62 ..