Question 1

Which of the following best describes the main advantage of using Gauss's Law to calculate electric fields?

Accepted Answer

It enables the use of symmetry to simplify field calculations.

Question 2

The electric flux through a flat surface of area $$A in a $$uniform electric field $$E is $$maximized when:

Accepted Answer

The surface is perpendicular to the electric field.

Question 3

A positive point charge $$q is $$placed at the center of a spherical Gaussian surface. What is the total electric flux through the surface?

Accepted Answer

$$\displaystyle \Phi_E = \frac{q}{\$$varepsilon_0$$}$$

Question 4

Which of the following statements about electric flux is correct?

Accepted Answer

Electric flux is proportional to the number of electric field lines passing through a surface.

Question 5

A cylinder of radius $$R$$ and length $$L is $$placed in a uniform electric field parallel to its axis. What is the total electric flux through the cylinder?

Accepted Answer

$$\displaystyle \Phi = 0$$

Question 6

For a nonconducting infinite plane sheet of charge with surface charge density $$\sigma$$, what is the magnitude of the electric field just outside the sheet?

Accepted Answer

$$\displaystyle E = \frac{\sigma}{2\$$varepsilon_0$$}$$

Question 7

A parallel plate capacitor consists of two large plates with equal and opposite charge densities $$+\sigma$$ and $$-\sigma. $$What is the electric field between the plates?

Accepted Answer

$$\displaystyle E = \frac{\sigma}{\$$varepsilon_0$$}$$

Question 8

The electric field inside a uniformly charged thin spherical shell is:

Accepted Answer

Zero everywhere inside the shell.

Question 9

A uniformly charged insulating sphere of radius $$R$$ has total charge $$Q. $$What is the electric field at a distance $$r \u003c R$$ from the center?

Accepted Answer

$$\displaystyle E = \frac{1}{4\pi\$$varepsilon_0$$} \frac{Qr}{R^3$}$$

Question 10

Which of the following is NOT a valid strategy when applying Gauss's Law?

Accepted Answer

Use a Gaussian surface that passes through the charges.

Question 11

A long straight wire carries a uniform linear charge density $$\lambda. $$What is the electric field at a distance $$R$$ from the wire?

Accepted Answer

$$\displaystyle E = \frac{\lambda}{2\pi\$$varepsilon_0$$ R}$$

Question 12

If the net charge enclosed by a Gaussian surface is zero, what can be said about the total electric flux through the surface?

Accepted Answer

The total electric flux is zero.

Question 13

A cube encloses a point charge $$q. If $$the cube is replaced by a sphere of the same volume, what happens to the total electric flux through the surface?

Accepted Answer

It remains the same.

Question 14

Which of the following best explains why the electric field outside a uniformly charged spherical shell is identical to that of a point charge?

Accepted Answer

The shell's charge acts as if it were concentrated at the center for points outside.

Question 15

A nonconducting plane sheet has a uniform surface charge density $$\sigma. $$What is the direction of the electric field just above the sheet?

Accepted Answer

Perpendicular to the sheet, away from the sheet if $$\sigma \u003e 0.$$

Question 16

Which of the following is the correct expression for the electric flux through a closed surface $$S in a $$non-uniform electric field?

Accepted Answer

$$\displaystyle \Phi_E = \int_S \vec{E} \cdot d\vec{A}$$

Question 17

A closed surface encloses both a $$+2\ \mu	ext{C}$$ and a $$-2\ \mu	ext{C}$$ point charge. What is the total electric flux through the surface?

Accepted Answer

$$\displaystyle 0$$

Question 18

Which of the following is true about the electric field between two large, oppositely charged parallel conducting plates?

Accepted Answer

The field is uniform and given by $$E = \frac{\sigma}{\$$varepsilon_0$$}.$$

Question 19

A Gaussian surface encloses a region with no net charge. Which of the following must be true?

Accepted Answer

The net electric flux through the surface is zero.

Gauss’s Law and Applications: Electric Flux and Symmetry in Electrostatics

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