What is the initial charge of the second object in Coulombs?

[JessicaHelena]

Homework Statement

Suppose an object has a charge of 1 C and gains #9.38 ✕ 10^18# electrons. When another object is brought in contact with the first object (after it gains the electrons), the resulting charge on the the second object is 0.9 C. What was the initial charge (in Coulombs)?

Homework Equations

1 electron has a charge of about #-1.6 \times 10^{-19}.

The Attempt at a Solution

Since the first object (call it object A) has a charge of 1C but gains #9.38 ✕ 10^18#, and using dimensional analysis #(9.38 ✕ 10^18 electrons) \times (-1.6 \times 10^{-19} C)/(1 electron) = -1.5008#, the net charge on object A is -0.5008 C. But I'm not sure how to go about solving for the initial charge on the second object?

 

[kuruman]

Even though the problem does not state so, the "objects" must be conductors for this to make sense. When the objects are brought in contact what do you think happens to the charges? Do they stay where they are or do they move?

 

[haruspex]

Even though the problem does not state so, the "objects" must be conductors for this to make sense.

And we need to assume the objects are identical, and brought into contact in a symmetric manner, no?

 

[kuruman]

And we need to assume the objects are identical, and brought into contact in a symmetric manner, no?

Yes.