Final answer:
When identical metal spheres with different charges contact, their charges redistribute evenly. Total charge is calculated by summing the initial charges and dividing by two.
Step-by-step explanation:
The question involves calculating the charge on metal spheres and determining the number of excess electrons or excess protons corresponding to the given charge. Charged metal spheres and their interaction through contact is a classic example of charge distribution and conservation of charge in physics.
When two conducting spheres are brought into contact, charges redistribute evenly because the spheres are identical. The total charge is simply the sum of individual charges, divided by two for each sphere (since both spheres will end up with the same charge).
For example, Sphere 1 with a charge of -9.6 × 10-18 C and Sphere 2 with 30 excess electrons (each electron having a charge of -1.6 × 10-19 C) will result in each sphere having an equal charge after contact.
The calculation for this involves adding the charge of Sphere 1 and the total charge contributed by the 30 excess electrons on Sphere 2, then dividing by two. Once we have the charge on each sphere, we divide it by the charge of a single electron to find the number of excess electrons.