2 Which of the following represents the electric field due to an infinite charged sheet with a uniform charge distribution σ.

Transcription

1 Slide 1 / 21 1 closed surface, in the shape of a cylinder of radius R and Length L, is placed in a region with a constant electric field of magnitude. The total electric flux through the cylindrical surface is πr 2 B zero 2πR L πr 2 L πrl

2 Slide 2 / 21 2 Which of the following represents the electric field due to an infinite charged sheet with a uniform charge distribution σ. B zero σ σ/2ɛ 0 2σ/Ɛ 0 σ/ɛ 0

3 Slide 3 / 21 3 Two large parallel sheets charged with equal but opposite charges. What is the electric field in the space between the sheets? zero B σ/ɛ 0 2σ/Ɛ 0 σ/2ɛ 0 σ

4 Slide 4 / 21 4 Two conducting concentric spherical shells are shown above. The electric field due to the charged shells is presented by field lines. What is the charge on the outer shell if the inner shell is charged with a positive charge Q. -2 Q B -Q 0 Q 2 Q

5 Slide 5 / 21 5 Which of the following statements about conductors under electrostatic conditions is true? harge placed on the conductor always spreads evenly throughout the entire volume. B harge placed on the conductor always spreads evenly over the surface. The charge surface density is always a constant. The electric field at the surface of a conductor is tangent to the surface. The electric field at the surface of a conductor is perpendicular to the surface.

6 Slide 6 / 21 6 The net electric flux through a closed surface B depends on the size of Gaussian surface depends on the shape of Gaussian surface is zero if only negative charges are enclosed by the Gaussian surface is zero if only positive charges are enclosed by the Gaussian surface is zero if the net charge enclosed by the Gaussian surface is zero

7 Slide 7 / 21 7 conducting sphere of radius R carries a charge Q. nother conducting sphere has a radius R/2, but carries the same charge. The spheres are far apart. The ratio of the electric field near the surface of the smaller sphere to the field near the surface of the larger sphere is most nearly 1/4 B 1/

8 Slide 8 / 21 8 In the region where r<a the electric field is proportional to Q 1 /r 2 B (Q 1 + Q 2 )/b 2 zero Q 1 /a + Q 2 /b Q 1 /a 2 + Q 2 /b 2

9 Slide 9 / 21 9 In the region a<r<b the electric field is proportional to Q 1 /r 2 B (Q 1 + Q 2 )/r 2 zero Q 1 /a + Q 2 /b (Q 1 +Q 2 )/r

10 Slide 10 / solid nonconducting sphere of radius R has a charge Q uniformly distributed throughout its volume. Gaussian surface of radius r with r < R is used to calculate the magnitude of the electric field at a distance r from the center of the sphere. Which of the following equations results from a correct application of Gauss's law for this situation? (4πR 2 ) = Q/ε o B (4πr 2 ) = Q/ε o (4πr 2 ) = (Q 3 r 3 )/(ε o 4πR) (4πr 2 ) = (Qr 3 )/(ε o R 3 ) (4πr 2 ) = 0

11 Slide 11 / sphere of radius R has positive charge Q uniformly distributed throughout its volume. Which of the following is the electric field inside the sphere r<r? 0 B kqr/r 3 kq/r 2 kq/r 3 kq/r

12 Slide 12 / sphere of radius R has positive charge Q uniformly distributed throughout its volume. Which of the following is the electric field outside the sphere r>r? 0 B kqr/r 3 kq/r 2 kq/r 3 kq/r

13 Slide 13 / sphere of radius R has positive charge Q uniformly distributed throughout its volume. Which of the following is the electric field outside the sphere r>r? B

14 Slide 14 / Gauss's law provides a convenient way to calculate the electric field outside and near each of the following isolated charged conductors XPT a B large plate sphere cube long, solid rod long, hollow cylinder

15 Slide 15 / The diagram below shows 2 oppositely charged parallel plates each with a uniform electric field. What is the magnitude and direction of the electric field at point? to the left B to the right zero no direction 2 to the right 2 to the left

16 Slide 16 / What is the magnitude and direction of the electric field at point B? B to the left to the right zero no direction 2 to the right 2 to the left

17 Slide 17 / uniform electric field with magnitude 3.0 x 10 3 N/ passes through a disk of radius 0.2 m 30 above the normal line as shown above. pproximately what is electric flux through the disk? 0 Wb B 60π 3 Wb 30π 3 Wb 20π 2 Wb 80π 5 Wb

18 Slide 18 / The figure below shows a cylindrical distribution of charge Q with radius R and constant charge density, #. Which of the following is the electric field inside the cylinder? B zero

19 Slide 19 / The figure below shows a cylindrical distribution of charge Q with radius R and constant charge density, #. Which of the following is the electric field outside the cylinder? B zero

20 Slide 20 / 21 20The figure below shows a cylindrical distribution of charge Q with radius R and constant charge density, #. Which of the following graphs best represents the electric field strength as a function of the distance r from the center of the cylinder? B

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