Download E and M Review for Final

E&M Review
AP Physics C
1. Describe Millikan’s Oil Drop experiment. What was the major conclusion?
2. Which is conclusive proof that an object has a net charge: that it is attracted to another object or that it is
repelled by another object? Explain.
3. If a negative force is calculated between two charged objects, what can you say about the nature of the
charge on each object?
4. Complete the following table:
Name
Formula
Coulomb’s
Law
Electric
Field
2 versions!
Electric
Potential
Difference
2 versions!
Electric
Flux
Gauss’ Law
Units
Description
A 1/r2 law that
describes the force
between charged
particles.
E is the negative
gradient of
.
5. Draw the electric field for the arrangements below. Indicate the direction of force on the electron drawn.
+Q
y
z
σ
x
∞ plane
6. Two point charges of unknown magnitude and sign are a certain distance apart. If the electric field is
zero at a point to the right of them on the line joining them, you can draw what conclusions?
7. Derive an equation to calculate the acceleration of a charge in an electric field.
8. Draw 3 situations in which Gauss’ Law would be a good way to determine the net charge present or the
value of the electric field.
9. Complete the following chart:
Charge distribution
Formula
Δ charge
Linear (λ)
λ= Q/L
dq=
Surface (
)
dq =
Volume (
)
dq =
10. Use Gauss’ law to find the electric field strength a distance r from an infinite line of positive charge.
11. Determine the electric field strength at a distance r from an infinite plane of charge.
12. Two hollow conducting spheres are concentric. The inner sphere has a net charge of +Q. The outer
sphere is neutral. Draw the spheres, label the charge values on the inner and outer surfaces of each
sphere, and draw any electric field lines that may be present.
13. If the spheres above have radii of a for the inner and b for the outer sphere, use Gauss’ Law to determine
the electric field for r<a, a<r<b, and r>b.
14. What is measured with the electron-Volt? How is it related to the normal SI unit for this measurement?
15. How are equipotentials related to electric field lines?
16. Four charges (+q, +q, -q, -q) are arranged at the corners of a square. Calculate the magnitude of the
electric field and the potential difference at the center of the square of side s.
17. Graph E vs. r and V vs. r for a hollow conducting sphere.
18. Define capacitance. Give the equation for the capacitance of a parallel plate capacitor.
19. Explain 3 ways to increase the capacitance of a capacitor.
20. Why is the energy stored in a capacitor less than the energy associated with moving the same amount of
total charge through the same potential difference?
21. Calculate the potential difference and the charge on each capacitor in the circuit below. What is the
equivalent capacitance?
3V
40 pF
20 pF
22. What factors affect the resistance of conductors? Explain their effects on resistance.
23. Analyze the circuit above. Label the current through each resistor as well as the potential difference
across each resistor.
24. Explain how you would measure the current and voltage in a circuit.
25. What is a time constant in an RC circuit? (equation, symbol, meaning…)
26. Draw Q vs. t for a charging RC circuit.
27. Draw I vs. t for a discharging capacitor in an RC circuit.
28. A 2.4 microFarad capacitor is charged by a 2.0 V battery. When the capacitor discharges through an
unknown resistor, the time constant is 15 ms. What is the value of the unknown resistor? What was the
maximum charge on the capacitor?
29. What is the major implication of Gauss’ Law for magnetism?
30. A long wire carries a 2.5 A current horizontally North. Give the magnitude and direction of the magnetic
field 10 cm away from the wire.
31. Calculate the force on the wire
the right if the magnitude of B is
segment to
1.5 Tesla.
32. A velocity selector is used to sort particles. What is the required velocity for a proton to pass undeflected
through the following fields? B = 0.22 T; E = 3.3x104 N/C.
33. In a mass spectrometer, an electron moving
speed of 1.0 x 108 m/s horizontally into a
field of 5.0 x 10-3 T. What is the radius of the
path?
with a
magnetic
resulting
34. Electric and Magnetic fields can affect the motion of charged particles. Explain how the forces from
each are similar and different. Include labeled diagrams and examples.