Rubber rods charged by rubbing with cat fur repel each other. ...

[itsmyluck]

Rubber rods charged by rubbing with cat fur repel each other. Glass rods charged by rubbing with silk repel each other. A rubber rod and a glass rod charged respectively as above attract each other. A possible explanation is that
 a. Any two rubber rods charged this way have opposite charges on them.
  b. Any two glass rods charged this way have opposite charges on them.
  c. A rubber rod and a glass rod charged this way have opposite charges on them.
  d. All rubber rods always have an excess of positive charge on them.
  e. All glass rods always have an excess of negative charge on them.

Question 2

One end of a copper rod is in thermal contact with a hot reservoir at T = 500 K and the other end is in thermal contact with a cooler reservoir at T = 300 K. Find the entropy change of each reservoir, and the total entropy change, when 8 000 J of heat energy are conducted from one end of the rod to the other with no change in the temperature distribution in the rod.

[FergA]

Answer to Question 1

C

Answer to Question 2

-16.0 J/K, +26.7 J/K, +10.7 J/K