164 ADVANCED ELECTRICITY AND MAGNETISM. 



between when an electromotive force of 10,000 volts is connected 

 to the plates. Ans. 0.00796 joule per centimeter or 79,600 dynes. 



6. What would the force of attraction of the plates of problem 

 5 be with an electromotive force of 100 volts? Ans. 7.96 dynes. 



7. The space between the plates in problem 5 is filled with oil 

 of which the inductivity is 2.5. What is the attraction of the 

 plates? Ans. 199,000 dynes. 



8. The electric field intensity at a point 200 centimeters from 

 the center of a uniformly charged sphere, say, 50 centimeters in 

 radius, is 250 volts per centimeter. The sphere is surrounded by 

 air. What is the charge on the sphere? Ans. o.ooooi 1 1 coulomb. 



