7.An uncharged metal sphere is placed in an otherwise uniforn electric field . Find the induced surface charge density.
(A) Zero everywhere on the sphere.
(B) ε₀E₀cosθ
(C) 2ε₀E₀cosθ 
(D) 3ε₀E₀cosθ

3.A charged particle at rest is released in a region of uniform electric field in the y direction and uniform magnetic field in the z direction. Which of the following statements is not correct? (A) The motion of the particle in the y direction is periodic. (B) In average, the particle moves with a constant speed in the x direction. (C) The kinetic energy of the particle increases with time. (D) The magnetic field does no work on the particle.

4. For an ideal electric quadruple, what is the relation between the electric field strength E and the distance r in the far field? (A)(B) (C) (D)

5.Consider two long parallel wires of radius a, separated by a distance d. If d□ a, find the capacitance per unit length. (A)(B) (C) (D)

6. In the static case, consider an interface between the free space and a perfect conductor with some charges on the surface. Which of the following statements is not correct? (A) The electric field in the free space near the surface is proportional to the surface charge density. (B) There is no electric field in the conductor. (C) The surface charge would experience no electric force. (D) The electric potcntial is the same in the conductor, even near sharp edges.

8.What does ρ in the Gauss's lawmean? (A) The free volume charge density. (B) The free surface charge density. (C) The sum of the polarization volume charge density and the free voiume charge density. (D) The sum of all surface charge density and volume charge density.

9.What does in the Ampcre's lawmean? (A) The free volume current density. (B) The free surface current density. (C) The sum of the polarization current density, the magnetization current density, and the free current density. (D) The sum of all surface current density and volume current density.

10. Consider a uniformly polarized dielectric sphere where the polarization inside the sphere is . Find the displacement ficld inside the sphere. (A)0 (B) (C)(D)

11. A short solenoid (length I, radius a, ni turns per unit length) lies on the axis of a very one solenoid (length /, radius b, na turns per unit length), where a＜b. What is the total magnetic flux through the long solenoid if a steady current / flows in the short aD solenoid? (A) μ0πa2n1n2ll (B) μ0πb2n1n2ll(C) μ0πa2n12ll(D)μ0πabn1n2ll

12. Which of the following statements is not correct in general? (A) Diamagnetism could be related to the orbital motion of electrons. (B)Paramagnetism could be related to the electronic spin. (C) Ferromagnetism becomes obvious above the Curie temperature. (D) Antiferromagnetism vanishes above the Neel temperature.

13. Consider a sheet current source at z = 0. The medium on either side of the sheet is free space. Which of the following statements for the region z ＞0 is not correct? (A) There will be a wave propagating in the +z direction. (B) The electric field and magnetic field are in phasc. (C) The instantaneous power flow out of an arbitrary closed surface is zero. (D) The average power flow is half of the peak power flow.