Beijing JIAO TONG UNIVERSITY
Terminal-examination of University Physics (II)
January 10, 2007
Class:_____________Student No.:_________ Name:__________
(I) (II) (III) Total Score
University Physics Exercises & Problems
(I) Choose one correct answer among following choices: (3 points of each)
1. Which of the following equations can be used to show that magnetic field lines form
closed loops? ;;;; A) B) E?ds？q/，B?ds？0(i0??SS;;;;
C) = –d，/dt D) = ：i + ：5d，/dt E?dlB?dlB000E??LL
[ B ]
;2ˆ2. The magnetic field in a region of space is given by for ；2s ? t ? +2s (in SI B？0.001ti
unit). What is the direction of the induced electric field when t = 0s?
A). Parallel to the x axis. B). Parallel to the y axis.
C). The electric field is in the circles centered on the x axis.
D). There is no induced electric field when t = 0s.
[ D ] 3.
;;What is the value of for the path shown in the B?ds?
figure? ；7A. ；8；?10 T?m ；7 B. ；4；?10 T?m ；7 C. +8；?10 T?m ；7 D. +32；?10 T?m
[ A ]
4. Magnetization ;磁化强度；is:
A) the current density in an object
B) the charge density of moving charges in an object
C) the magnetic dipole moment (磁偶极矩) of an object
D) the magnetic dipole moment per unit volume of an object
[ D ]
5 . A consequence ;结果；of Einstein's theory of relativity is:
A) everything is relative
B) moving rods are longer than when they are at rest
C) moving clocks run more slowly than when they are at rest
D) the laws of physics must appear the same to all observers moving with
uniform velocity relative to each other
[ C ]
6. Two events occur simultaneously at separated points on the y axis of reference frame S.
According to an observer moving in the positive x direction:
A) the events are simultaneous
B) the event with the greater y coordinate occurs first
C) the event with the greater y coordinate occurs last
D) either event might occur first, depending on the observer's speed
[ A ]
7. The proper time (原时)between two events is measured by clocks at rest in a reference frame
in which the two events:
A) occur at the same time
B) occur at the same location (position)
C) are separated by the distance a light signal can travel during the time interval
D) satisfy none of the above
[ B ]
8. Which of the following electromagnetic radiations has photons with the greatest energy?
A) radio waves
B) blue light
D) yellow light
[ C ] 9. The Compton effect demonstrates ;表明；
A) light acts as photons
B) relativistic formulation works well
C) consistent;一致的；explanations of scattered photon shift in wavelength
D) all of the above
[ D ]
2 10. The significance ;意义；of ??? is:
A) probability density
D) energy density
[ A ]
II) Fill in the blank with correct answer:
(dE1. (3 points) Displacement current (位移电流) is:____________________________ ，0dt
2. (3 points) As the figure shown, uniform electric current flows i i . into and then out from a circular ring. The magnetic field at the o
center of the ring should be:______0_______
3. (4 points) A rod with resistance R lies across frictionless conducting rails ;轨道；in a
constant uniform magnetic field B, as shown. Assume the rails have negligible resistance.
The force that must be applied by a person to pull the rod to the right at constant speed v
22is:____ _______BLv/R __________ _____ _____________.
4. (4 points) A cylindrical (圆柱的) region of radius R = 3.0 cm contains a uniform magnetic