D) Conservation of Charge - net charge of closed system remains constant

 

If 2 charges OR MORE are brought together their combined charge is distributed evenly

 

Before contact
 
After contact

                    

Charge evenly distributed


Total charge before =

total charge after

 

 

 

Ex) Metal sphere A has a charge of +12 elementary charges and identical sphere B has a charge of +16 elementary charges.

After the two spheres are brought into contact, the charge on sphere A is

a)+28 elem. charges  c)+2 elem. charges
b)-2 elem. charges  d)+14 elem. charges

 

 

d)+14 elem. charges

Conservation of Charge

 

 

E) Elementary Charge - smallest charge known to exist in nature


Charges come in whole number multiples of 1.6 X 10-19 coulombs

 


p   +1.6 x 10-19 C

Reference

e   -1.6 X 10-19 C

Reference

 

How many excess charges are there in an object with a charge of
-9.6 x 10–19 C?

 

 

6 excess electrons,


Divide by 1.6 X 10-19 coulombs

To find # of

elementary charges

 

A metal sphere -1.1 × 10-6 C. How many more electrons than protons are on the sphere?

a) 1.8 × 1012 b) 5.7 × 1012
c) 6.9 × 1012 d) 9.9 × 1012

 

 

Divide by 1.6 × 10-19 C

c) 6.9 × 1012 electrons

 

 

An object can not have a charge of

a) 3.2 x 10-19 C b) 4.5 x 10-19 C
c) 8.0 x 10-19 C d) 9.6 x 10-19 C

 

 

b) 4.5 x 10-19 C


(not an even multiple
of 1.6 x 10-19 C)