G12 ADV Gauss

In order to use Gauss’s Law to calculate the electric field created by a known distribution of charge, which of the following must be true?

• The charge distribution must be in a nonconducting medium

• The charge distribution must be in a conducting medium

• The charge distribution must be uniform

• The charge distribution must have a high degree of symmetry that allows assumptions about the symmetry of its electric field to be made

Four charges are placed in three-dimensional space. The charges have magnitudes +3q, −q, +2q, and −7q. If a Gaussian surface encloses all the charges, what will be the electric flux through that surface?

• −13q/E0

• −3q/E0

• 3q/E0

• 13q/E0

The figure below shows a distribution of charges. The flux of the electric field due to these charges through the surface E is _____.

• 0

• q/Eo

• 2q/Eo

• 3q/Eo

The figure below shows five Gaussian surfaces (F G/ .) surrounding a distribution of charges. Which surface has a flux of Q/E0

• a

• b

• c

• d

Which Gaussian surface has no electric flux through it?b

• a

• b

• c

• d

The electric flux through a spherical Gaussian surface of radius R centered about an amount of charge Q is 1200 N/C m². What is the electric flux through a cubic Gaussian surface of side R centered about the same charge Q?

• Less than 1200

• More than 1200

• Equal to 1200

• It cannot be determined with the given parameters

The diagram below shows three charges q1,q2 and q3, all lying in the plane of the page. The diagram also shows the circle that represents the cross-section of a spherical Gaussian surface. Which of the charges contributes to the electric field at a point on the Gaussian surface?

• q1 and q2

• q1 and q3

• q1, q2 and q3

• none of the charges

Consider the four cases shown below. Each one contains either a charge q or a charge 2q. A Gaussian surface surrounds the charged particle in each case. Considering the electric flux through each of the Gaussian surfaces, which of the following comparative statements is correct

• 1=3 less  than 2=4

• 1=3 greater than 2=4

• 1=2 less than 3=4

• 3=4 greater than 2=3

Two concentric spherical surfaces are drawn around an isolated positive charge +q located at their center. The inner surface has a radius that is 1/2 that of the outer surface. If the total electric flux passing through the inner surface is Φ, what is the total electric flux passing through the outer surface?

• Φ/4

• Φ/2

• 2Φ

• Φ

A point charge, +Q, is located on the x-axis at x = a, and second point charge, −Q, is located on the x- axis at X = −a. A Gaussian surface with radius R = 2a is centered at the origin. The flux through this Gaussian surface is ____.

• 0

• 2Q/ε0

• more than 0

• less than 0