Question

N object has a charge of -2.0 μc. how many electrons must be removed so that the charge becomes +2.2 μc?

Answer 1

Electrical Charge is a property of matter that causes it to experience a force when place in an electromagnetic field. Charge is measured in coulombs.
The change in the charge is 2.2- (2.0)= 4.2 μ c.
1 electron has a charge of 1.6 ×10∧-19 coulombs
Therefore, the number of electrons will be;
        = (4.2 ×10∧-6)/ (1.6 ×10∧-19)
        = 2.625 × 10∧13 electrons

Answer 2

Current charge = -2.0 micro C
 Charge needed = +2.2 micro C
 So the net charge is 4.2 micro C
 The charge on one electron = -1.602 x 10^-19 C
 Calculating the net change in the number of electrons = 4.2 x 10^-6 / -1.602 x 10^-19 = - 2.621 x 10^13
 The negative sign implies the number of electrons that needs to be removed that is 2.621 x 10^3