Chapter 14: Q64P (page 585)

The diagrams in Figure 14.98 show a sequence of events involving a small lightweight aluminum ball that is suspended from a cotton thread. In order to get enough information, you will need to read through the entire sequence of events described below before beginning to answer the questions. Before trying to select answers, you will need to draw your own diagrams showing the charge state of each object in each situation. (a) A small, lightweight aluminum ball hangs from a cotton thread. You touch the ball briefly with your fingers, then release it (Diagram 1 in Figure 14.98). Which of the diagrams in Figure 14.99 best shows the distribution of charge in and/or on the ball at this moment, using the diagrammatic conventions discussed in this chapter? (b) A block of metal that is known to be charged is now moved near the ball (Diagram 2 in Figure 14.98). The ball starts to swing toward the block of metal, as shown in Diagram 3 in Figure 14.98. Remember to read through the whole sequence before answering this question: Which of the diagrams in Figure 14.99 best shows the distribution of charge in and/or on the ball at this moment? (c) The ball briefly touches the charged metal block (Diagram 4 in Figure 14.98). Then the ball swings away from the block and hangs motionless at an angle, as shown in Diagram 5 in Figure 14.98. Which of the diagrams in Figure 14.99 best shows the distribution of charge in and/or on the ball at this moment? (d) Finally, the block is moved far away. A negatively charged rod is brought near the ball. The ball is repelled by the charged rod, as shown in Diagram 6 in Figure 14.98. Which of the diagrams in Figure 14.99 best shows the distribution of charge in and/or on the ball at this moment?

Short Answer

Expert verified

(a) Diagram K best shows the distribution of charge in and/or on the ball at this moment.

(b) Diagram C and D best show the distribution of charge in and/or on the ball at this moment.

(d) Diagram J best shows the distribution of charge in and/or on the ball at this moment.

Step by step solution

Significance of the electric field

The electric field is described as a region that helps an electrically charged particle to exert force on another particle.

(a) Determination of the diagram that best shows the distribution of charge in and/or on the ball at this moment

The first diagram shows that the aluminum ball hangs from the thread and is suddenly released. However, if the metal ball is being touched, then the ball gets neutralized. Hence, no net charge acts inside the ball only the negative charges act outside the ball and most of the negative charges are on the right side of the ball.

Thus, diagram K best shows the distribution of charge in and/or on the ball at this moment.

(b) Determination of the diagram that best shows the distribution of charge in and/or on the ball at this moment

Diagram 2 shows that the metal block moves near the ball. Diagram 3 shows that the ball swings towards the metal block. However, it can be identified that the block has induced a charge distribution on the spheres. Hence, the diagrams may have dipoles in the same or in the opposite direction and will have positive and negative charges on either side of the sphere.

Thus, diagrams C and D best show the distribution of charge in and/or on the ball at this moment.

(c) Determination of the diagram that best shows the distribution of charge in and/or on the ball at this moment

Diagram 4 shows that the ball touches the charged block of metal. In diagram 5, the ball swings away from the block and motionlessly hangs at a particular angle. Hence, the diagram can be dipoles having positive charges at the right or at the left and the same goes for the negative charges.

Thus, diagram A and B best shows the distribution of charge in and/or on the ball at this moment.

(d) Determination of the diagram that best shows the distribution of charge in and/or on the ball at this moment

A rod that is negatively charged has been brought near the ball in diagram 6. Moreover, the charged rod repels the ball. Hence, it shows that the ball has negative charges all over its surface and the greater number of negative charges is on the right side of the ball.

Thus, diagram J best shows the distribution of charge in and/or on the ball at this moment.