Physics Exam E&M - M (G12)

A particle with no net charge is traveling to the left

when it enters the space between two oppositely

charged parallel plates as shown below.

Which of the labeled paths will the particle take?

• A

• B

• C

• D

• E

A small metal sphere X is charged by losing 500

electrons. An identical metal sphere Y is charged by

gaining 1000 electrons. The two spheres are first put

in contact with each other and then separated. If -e is

the charge on an electron, what is the charge on each

sphere after separation?

Sphere X Sphere Y

• +500 𝑒 +500 𝑒

• +250 𝑒 +250 𝑒

• −250 𝑒 +250 𝑒

• −250 𝑒 −250 𝑒

• −500 𝑒 −500 𝑒

A positively charged rod is initially far from a neutral, grounded conductor and is then brought close to the conductor without touching it. If the ground wire is removed while the charged rod is near the conductor, what is the net charge on the conductor?

• Positive

• Negative

• There is no net charge on the conductor

• The conductor is charged, but the sign of the charge is unknown

• It cannot be determined without knowing the shape of the conductor

At the instant shown in Figure 1, a particle with

charge −q is moving with speed 𝑣 in the +x - direction. An electric force is exerted on the particle in the +y -direction, as shown in the free-body diagram in Figure 2. In which direction is the acceleration of the particle?

• A

• B

• C

• D

• E

The figure below represents an electric field

created by charged objects that are not shown. The

field vectors and the locations X, W and Z are in the

plane of the page. A small charged bead held inside

the electric field has an electric force exerted upon it.

At which location does the electric force have a

greater magnitude?

• X

• W

• Z

• Neither; the magnitude of the force is the

  same at all locations

• It cannot be determined without knowing

  the sign of the charge on the bead

A very small ball has a mass of 0.008 kg and a

charge of 2.00 μC. What magnitude electric field

directed upward will balance the weight of the ball

so that the ball is suspended motionless above the

ground?

• 7.84 × 10^-2 N/C

• 3.92 × 10⁴ N/C

• 4.00 × 10³ N/C

• 1.60 × 104 N/C

• 8.21 × 10² N/C

An electron is released from rest in an area where

it is in the electric field of solid conducting sphere

that has a large net positive charge. Which graph

would best represent the movement of the electron

after its release? (Assume the only force on the

electron is from the large positive charge).

• I only

• II only

• III only

• I and II only

• I and III only

The figure below shows three objects 𝑋, 𝑌 and 𝑍

that have charges – 4𝑞,+𝑞 and – 𝑞, respectively. The

objects are held fixed on an axis at the positions

shown. The magnitude of the electrostatic force

exerted by object 𝑌 on object 𝑍 is 𝐹. What is the

magnitude of the net electrostatic force exerted on

object 𝑌 due to the other two objects?

• 0

• 2F

• 3F

• 4F

• 5F

The figure below shows a distribution of charges.

The flux of electric field due to these charges through

the surface is ______.

• 
• 
• 
• 
• zero

Two charged particles, 𝑄₁ = + 12.0 𝑚𝐶 and 𝑄₂ = −5.0𝑚𝐶 are placed on a line. At what finite locations along the line may the electric potential be equal to zero?

I. in between the particles, closer to the positive particle

II. in between the particles, closer to the negative particle

III. not in between, but closer to the positive particle

IV. not in between, but closer to the negative particle

V. It can never be zero

• I only

• II only

• V only

• I and IV only

• II and IV only