Problem 1
Find the total positive charge of all the protons in \(1.0 \mathrm{mol}\) of
water.
Problem 2
Suppose a 1.0 -g nugget of pure gold has zero net charge. What would be its
net charge after it has \(1.0 \%\) of its electrons removed?
Problem 3
A balloon, initially neutral, is rubbed with fur until it acquires a net
charge of \(-0.60 \mathrm{nC} .\) (a) Assuming that only electrons are
transferred, were electrons removed from the balloon or added to it? (b) How
many electrons were transferred?
Problem 4
A metallic sphere has a charge of \(+4.0 \mathrm{nC} .\) A negatively charged
rod has a charge of \(-6.0 \mathrm{nC} .\) When the rod touches the sphere, $8.2
\times 10^{9}$ electrons are transferred. What are the charges of the sphere
and the rod now?
Problem 5
A positively charged rod is brought near two uncharged conducting spheres of
the same size that are initially touching each other (diagram a). The spheres
are moved apart and then the charged rod is removed (diagram b). (a) What is
the sign of the net charge on sphere 1 in diagram b? (b) In comparison with
the charge on sphere \(1,\) how much and what sign of charge is on sphere \(2 ?\)
Problem 6
A metal sphere A has charge \(Q\). Two other spheres, B and \(\mathrm{C},\) are identical to \(\mathrm{A}\) except they have zero net charge. A touches \(\mathrm{B}\), then the two spheres are separated. B touches \(C\), then those spheres are separated. Finally, C touches A and those two spheres are separated. How much charge is on each sphere?
Problem 9
If the electric force of repulsion between two \(1-\mathrm{C}\) charges is $10
\mathrm{N}$, how far apart are they?
Problem 10
Two small metal spheres are \(25.0 \mathrm{cm}\) apart. The spheres have equal amounts of negative charge and repel each other with a force of \(0.036 \mathrm{N}\). What is the charge on each sphere?
Problem 11
What is the ratio of the electric force to the gravitational force between a
proton and an electron separated by \(5.3 \times 10^{-11} \mathrm{~m}\) (the
radius of a hydrogen atom)?
Problem 12
How many electrons must be removed from each of two 5.0 -kg copper spheres to
make the electric force of repulsion between them equal in magnitude to the
gravitational attraction between them?
