Short Answer 
When two identical metal spheres come into contact, they can share electrons, resulting in sphere A receiving 1.0 × 10¹² electrons, leading to a total charge of −1.6 × 10⁻⁷ C. This charge is evenly divided when the spheres are separated, resulting in each sphere having a charge of −8 × 10⁻⁸ C, or −80 nC.
Step 1: Understand Electron Transfer
When two identical metal spheres come into contact, they can share electrons. In this scenario, the number of electrons transferred to sphere A is given as 1.0 × 10¹². Each electron has a charge of −1.6 × 10⁻¹⁹ C, which means they play a crucial role in determining the overall charge of the spheres.
Step 2: Calculate Total Charge
To find the total charge carried by the electrons transferred to sphere A, use the formula:
- Multiply the number of electrons (1.0 × 10¹²) by the charge of one electron (−1.6 × 10⁻¹⁹ C).
- This calculation yields a total charge of −1.6 × 10⁻⁷ C.
- This charge is initially shared between both spheres when they are in contact.
Step 3: Determine Charge on Each Sphere
Since the charge is evenly distributed between the two spheres when separated, the charge on each sphere can be found. The calculation is:
- Divide the total charge (−1.6 × 10⁻⁷ C) by 2, which results in −8 × 10⁻⁸ C.
- This value is equivalent to ‚àí80 nC, which is the charge on both sphere A and sphere B after they are separated.