中南大学双语物理.试卷评分标准.docVIP

PAGE  PAGE 3 Question One. Fill in the blanks（28 marks total，4 marks each） 1． (2 points) , (2 points) 2． (4 points) 3． (4 points) 4．B = 5.1?10?2 T ; (2 points) U = 0.1 J. (2 points) 5．Bm= 1.07?10?12 T. (2 points) um = 9.12?10?19 J/m3. (2 points) 6． 1.8 eV=2.88?10?19 J. (4 points) 7. (a) 13.6 eV, (2 points) (b) 3.4eV. (2 points) Question Two. Multiple-choice questions.（30 marks total，3 marks each） 1d, 2c, 3b, 4c, 5b, 6d, 7a, 8c, 9d, 10d Question Three. Calculation problems (40 marks total, 10 marks each) 1． Solution: (a) The linear charge density is given by (1 points) (b) Choose an element charge on the rod The electric potential produced by dq at point P is . (2 points) From the superposition of electric potential, then the net electric potential at point P is , (1 points) or (1 points) (2 points) (c) For, Using the series expansion for , we have is just the electric potential of a point charge. (3 points) 2． (2 points) (b) Take a spherical surface centered with the solid nonconducting charged sphere as Gaussian surface. From Gauss’ law, we have , (2 points) For r R, The charge enclosed by the Gaussian surface is (2 points) (2 points) For r R, (2 points) 3. (1 point) (1 point) (1 point) (2 points) Direction: (1 point) 4．(a) From Faraday’s law of induction, the induced emf in the circuit is (2 points) (2 points) (1 point) For