Elementary Charges
What are the most basic elementary charges that have electric charge?
Protons and electrons
What would happen if there is a negative charged object and a positive charged object next to each other?
They would attract
What is the charge on 1 proton and 1 electron?
q= +1.6 x 10-19 C and q= -1.6 x 10-19 C
What is the type of electrostatic force?
Vector
What is the electric field between 2 oppositely charged parallel plates?
Positive to negative
Net charge is the same thing as...
the total charge of an object
They would repel
What is true about the variable n? (number of charges)
n is always positive
What is the relationship between electric foree and charge?
Direct relationship
If there is a negative charged object, what are the directions of the electric field, the force on proton, and force on electron?
The electric field and force on proton is direct towards the negative charged object while the force on electron is directed away from the negative charged object
What are the charges for a proton, an electron, and a neutron?
+1e, -1e, 0e
What happens when substances are rubbed together?
It causes a transfer of electrons
q=ne
q= -2500 e (1.6 x 10-19 C) = +4 x 10-16 C
If sphere A has a charge of -3.0 x 10-6 C and sphere B has a charge of -6.0 x 10-6 C, which object experiences a greater force?
The electrostatic force is the same due to Newton's 3rd Law
The electric field intensity at a point is 4.0 x 105 N/C. What is the force that a 5.5 x 10-6 C charge experiences at that point?
Fe= Eq
=4.0 x 105 N/C (5.5 x 10-6 C) = 2.2 N
How does an atom become positively charged?
It must lose electrons
Explain what happens when the rubber rod and fur are rubbed together.
Electrons rubbed off the fur by friction onto the rod. The rod becomes negative (gains e) and fur become positive (lose e)
Give one possible charge for an object to have.
-3.2 x 10-19 C
Calculate the electric force from above if there centers are 75 centimetres apart.
Fe= 9 x 109 Nm2/C2 (-3 X 10-6 C) (-6 X 10-6 C) / (.75m)2
Fe= .288 N
A positive charge of 1.5 x 10-5 C experiences a force of .26 N when located at a certain point in an electric field. What is the electric field strength at that point?
E= Fe / q
=.26 N / 1.5 x 10-5 C = 17,333 N/C
Why aren't protons normally gained or lost by atoms when they become charged?
Explain what happens when plastic strip and fabric are rubbed together.
Electrons rubbed off the plastic by friction onto the fabric. The fabric becomes negative (gains e) and the plastic becomes positive (loses e)
How can you determine if a charge is possible?
Electrons come in whole numbers only. So the charge must be a multiple of 1.6 x 10-19 C
What are the differences between gravitational force and electrostatic forces?
Gravitational forces attract only while opposite forces attract (-) and likes repel (+) in electrostatic force. Also, Fe > Fg always
Name 3 properties of Electric Field Lines
1) E-Field lines never cross each other
2) show the direction of force on a small positive test charge out of positive into negative
3) Number of field lines represent relative strength