Answer the following questions in the spaces provided or on a separate sheet of paper. Remember to employ proper problem-solving techniques throughout, that is, list all given information, equations, substitutions, and show all work. Units must be included at each step in the problem-solving process. Consult your Reference Tables, class notebook and textbook freely.
Useful Constants, Concepts, and Equations
1 Coulomb = 6.25 x 10exp18 elementary charges
1 elementary charge = 1.60 x 10exp-19 Coulomb
1 electron = -1.60 x 10exp-19 Coulomb
1 proton = +1.60 x 10exp-19 Coulomb
All matter is composed of charges
Electrons are weakly bound to the nucleus whereas protons are strongly bound to the nucleus.
Electrons are mobile whereas protons are not.
Electrons possess a net negative charge whereas protons possess a net positive charge.
The charge magnitude possessed by electrons and protons is the same but of opposite sign.
Unlike charges attract whereas like charges repel.
Electric fields permeate the space around every charged object.
Electric field lines illustrate the trajectory of a positive test charge when brought into the field of a charged object.
Electric field lines always intersect the surface of a charged object at right angles.
Electric field lines never cross.
Static electric charges gather on the surfaces of objects only.
The magnitude of the electric field inside a charged object is zero.
Electric forces are attractive as well as repulsive.
Conductors are bodies which easily permit the flow of electrons through them whereas insulators do not.
All matter can be made to conduct electricity provided there is sufficient emf (electromotive force).
Charge balance is always sought between two charged objects in contact.
Charges of whole number multiples of the elementary charge are possible only.
Fe = kq1q2/dexp2
E = Fe/q
V = W/q
I = qtot/t
Fe is electric force (N), k is 9.0 x 10exp9N-mexp2/Cexp2, q1, q2 are charges of two objects respectively (C) separated by distance d (m); E is electric field intensity (N/C), q is positive test charge placed in field (+C), W is work (J), V is potential difference (volts); I is current (ampere), qtot is total charge passing a given point (C) and t is time (s).
1. Calculate the charge possessed by two objects q1 and q2 with
values of -12C and +5C after they are connected with a conducting
2. Calculate the Fe between two charges each possessing a value of
-5C and separated by a distance of 5 m.
3. Calculate the E at a distance of 2 m when a test charge of +3.20 x
10exp-15C is placed in the field produced by a charge of +1.60C.
4. Calculate the amount of work done in moving +5C across a
potential difference of 440 volts.
5. Calculate the number of electrons which pass a given point in a
wire which is experiencing a current of 20 amperes over a 1 hour
6. Assuming a uniform, steady state flow of current in a wire which
only permits one electron to exit at a time, calculate the amount of
time it takes between successive electrons to exit the wire if it is