Summary

• Electric charge
• Definitions

• Electrical forces
  • action at a distance
  • charging by induction
  • Coulomb's law
  • induced charges
  • neutral objects
  • compare with gravity
    Example #1
    
    Example #2
    
    Example #3
    
    
  • microscopic vs. galactic forces
  
  

kw4
Two small spheres separated by 2 m contain negative charges of 2 C and 3 C. What is the electric force between them?
A. +1.35×10¹⁰ N       B. -1.35×10¹⁰ N
C. +2.70×10¹⁰ N       D. -2.70×10¹⁰ N
Answer







gc6 16.2
How many electrons make up a charge of -30.0 µC?
A. 3.00×10^-6          B. 3.33×10⁵
C. 1.87×10¹⁴         D. 6.25×10¹⁸
Answer







sb5 23.5
Suppose 1.0 g of hydrogen is split with the protons on the north pole and electrons on the south. What is the compression force on the earth?
A. 5.74×10^-42 N       B. 1.73×10² N
C. 6.55×10⁴ N         D. 5.14×10⁵ N
Answer







 



A. +1.35×10¹⁰ N













 



C. 1.87×10¹⁴













 



D. 5.14×10⁵ N