4.1

Exam Date – Wed 2/9

Topics Covered Listed on Class Website Sample Exam from a few years back is also on the web.

Today

Start Unit 5: Electric Potential (Energy Methods)

Wednesday



Monday

More of the same

Friday: Surprise – Quiz #2 (for real!)

Spring Break is just a few weeks away – (5ish)

The figure shows the electric field lines in the vicinity of two point charges. Which one of the following statements concerning this situation is true?

A)

q

1 is negative and

q

2 is positive.

B) The magnitude of the ratio (

q

2 /

q

1 ) is less than one.

C) Both

q

1 and

q

2 have the same sign of charge.

D) The magnitude of the electric field is the same everywhere.

E) The electric field is strongest midway between the charges.

A cubical Gaussian surface is placed in a uniform electric field as shown in the figure. The length of each edge of the cube is 1.0 m. The uniform electric field has a magnitude of 5.0 × 10 8 N/C and passes through the left and right sides of the cube perpendicular to the surface. What is the total electric flux leaving the cubical Gaussian surface?

A) 5.0 × 10 8 m 2 /C B) 3.0 × 10 9 N×m 2 /C C) 2.5 × 10 6 N×m 2 /C D) 1.5 × 10 7 N×m 2 /C E) zero N×m 2 /C

What is the electric flux passing leaving a Gaussian surface that surrounds a +0.075 C point charge?

A) 8.5 × 10 9 N×m 2 /C B) 6.8 × 10 8 N×m 2 /C C) 1.3 × 10 7 N×m 2 /C D) 4.9 × E) 7.2 × 10 6 N×m 2 /C 10 5 N×m 2 /C  

q inside

e 0 e 0= 8.85×10 −12 SI Units

A solid, conducting sphere of radius charge of +6

a

carries an excess µ C. This sphere is located at the center of a hollow, conducting sphere with an inner radius of

b

and an outer radius of

c

as shown. The hollow sphere also carries a total excess charge of +6 µ C.

Determine the excess charge on the

outer surface

of the outer sphere (a distance

c

from the center of the system).

A) zero coulombs B) – 6 m C C) +6 m C D) +12 m C E) – 12 m C

+

Mrs. Field Mr. External

Mrs. Field Mr. External

E

That was HARD WORK Mr. External

+ charge

Sure Was Mrs. Fields Mrs. Field Mr. External

Each does the negative amount of work that the other one does.

Constant Speed

The net work done by a conservative (field) force on a particle moving around a closed path is

ZERO!

The work necessary for an external agent to move a charge from an initial point to a final point is INDEPENDENT OF THE PATH CHOSEN!

A conservative force is NOT a Republican.

An External Agent is NOT 007.