|0.|| Look around your house for examples, what are the applications of the following topics of Physics 2:
List all appliances and think about how each appliance works. Everybody uses physics and engineering everyday !
|1.|| What is the SI unit for electric charge?
'C' for Coulombs
|2.|| What is the charge of 1 electron?
|3.|| Sketch the electric field lines for (a) neutral particle, (b) positive charge
and (c) negative charge:
(a) A neutral charge does not have an electric field
(b) For a positive charge, electric field lines point outward
(b) For a negative charge, electric field lines point inward
|4.|| Sketch and solve for resultant electric field force acting on a particle, q1,
which is near two charged particles, q2 and q3 as shown below?
Assume the following:
(a) Particle q1 is positive whilst particles q2 and q3 are negative;
(b) Particle q1 is negative whilst particles q2 and q3 are positive;
(c) Particle q1 is positive whilst particles q2 and q3 are positive;
Hint : Sketch free-body diagrams of electric field forces on particle q1 alone for all three cases separately. YES, free body diagrams apply to electric fields as well - wherever there are forces, free-body diagrams are there. Show answer
This is a vector addition problem, review vector addition from Physics 1 before attempting the problem. Just like contact forces, electric field force is a vector (it has magnitude and direction).
Note that the free body diagram is just showing particle q1 and forces that act on q1.
Forces F21 and F31 in part (b) are equal in magnitude and direction to those in part (a).
Forces F21 and F31 in part (c) are equal in magnitude, but opposite in direction to those in part (a) and (b).
It should be noted that the magnitude of the resultant force is the same in all 3 cases. Direction changes for part (c) only.
Calculate F21 and F31 using the following equation:
Review the formula for solving electric field force, the denominator is the distance between particles. Do you understand how to solve for distance between q1 and q2?
The angle between F21 and the horizontal is determined by taking inverse tangent. Remember SOH CAH TOA
This is called 'Cosine Rule', read more about it here.
|5.|| One important application of electric fields is electrostatic spray painting of cars.
Assume that at Joe Bob's Body Shop near your house, paint particles are charged to -2C whilst
the car is positively charged. It so happens that you are
hired as an intern by Mr J. Bob. As part of your job,
you explain and demonstrate how electrostatic spray painting works to potential customers.
Answer the following questions to demonstrate you are the most
qualified intern for the job:
|6.|| You decide to reject your internship offer from Joe Bob's Auto Body because
eventually you want to be a medical doctor/nurse. Instead, you accept
an internship offer to work at a local children's hospital. During your
new intern orientation you are told to always wear your
work shoes while you are in the operating room. The reason for wearing
those 'special shoes' is
to conduct any electrostatic charge you may acquire to the hospital floor. Electrostatic charges can
cause fires (especially if you work with flammable anaesthetic drugs)
or malfunction of equipment in operating rooms. Answer the following
questions to demonstrate you are a prepared intern:
I highly recommend you read Preventing preventing preventing fires and explosions in the operating room by Noyce L. Griffin
|7.|| What is the SI unit for capacitance?
'F' for Farads
|8.|| As a curious physics student, you decide to have hands-on experience
with capacitors. You head over to a local RadioShark store to buy
a 1000 micro-Farad capacitor so that you can take it apart.
Answer the following questions before you can take it apart:
Image of a capacitor from RadioShark Show answer
|9.|| What are the SI units of the following electrical quantities?
Review textbook chapters