Download 08. Elect,_Coulomb`s_Law,_Fields

Final Exam Review
Static Electricity
Coulomb’s Law
Electric Fields
Static Electricity
• Key Point: Occurs when one object takes
electrons from another.
• Example: Rubbing your hair with a balloon.
- - - -
Coulomb’s Law
• Formula:
•
Felec= kC(q1q2)/r2
• The force between two charges q1 and q2,
separated by a distance r.
• kC is a constant and equals 8.99 x109 Nm2/kg2
Elementary Charge
• The charge on either 1 proton OR 1 electron
is:
• 1.60 x 10-19 C for a Proton
• -1.60 x 10-19 C for an Electron
Example
• The electron and proton of a hydrogen atom
are separated, on average, by a distance of
about 5.3 E-11 m. Find the magnitude of the
electric force between the particles.
Example
• The electron and proton of a hydrogen atom
are separated, on average, by a distance of
about 5.3 E-11 m. Find the magnitude of the
electric force between the particles.
• Givens: r = 5.3 E-11 m q1=1.6E-19 C
•
kC=8.99E9 Nm2/s2 q2=-1.6E-19 C
Example
• The electron and proton of a hydrogen atom
are separated, on average, by a distance of
about 5.3 E-11 m. Find the magnitude of the
electric force between the particles.
• Givens: r = 5.3 E-11 m q1=1.6E-19 C
•
kC=8.99E9 Nm2/s2 q2=-1.6E-19 C
• Felec= kC(q1q2)/r2
Example
• The electron and proton of a hydrogen atom
are separated, on average, by a distance of
about 5.3 E-11 m. Find the magnitude of the
electric force between the particles.
• Givens: r = 5.3 E-11 m q1=1.6E-19 C
•
kC=8.99E9 Nm2/s2 q2=-1.6E-19 C
• Felec= kC(q1q2)/r2
• Felec= 8.99E9 (1.6E-19 * -1.6E-19) / (5.3E-11)2
• Felec = -8.2 E-8 N
Practice
• Pg 566- Practice A
• #2a, 3
Electric Field Mapping- Examples
• 1 electron and 1 proton
-q
+q
Electric Field Mapping- Examples
• 2 Protons
+q
+q
Electric Field Mapping- Examples
• 2 Electrons
-q
-q