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A laboratory manual for high schools, colleges, and universities, this book contains more than 80 experiments and lecture demonstrations. The coverage includes the essentials of general physics: mechanics and molecular physics, electricity and magnetism, optics and atomic physics, and condensed matter physics. All the experiments are illustrated through the results of real measurements and include many novel experiments developed by the author.
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Yaakov Kraftmakher EXPERIMENTS AND Bar-Man Physics Laboratory E wtffcwHf B8p"88n Ban"""" B 8 8 " S 8 B D M BOOH J 8 8 & nKKK™" U R B 8 & S8B888BS JMBWHI u n n looooT MB TOW OK BJHTWHB "™ BBofc Joflgl H a MB- JnnB ffinfi , BB^^HF n f l H n U B W B Win 1BPP\ W > g n t t SSat SB MOT^ iBoW a88ft flflflffi fbofiook JsBm n ^ WBm 5f«[ m BWB iHp* BraB B ^^fe nW H » 5 8 BBBBBBB BB B R S 9 Hi & M8BBBW B VSt 15 *SSBr «w s88a RBH &BW88BV Won PJBJ Wm THm M O M BOB wBSt MOt fll B i n m MS m m wH SBSSW^ Physics S-. \ — ^ ^ mrafflU V | H | O 5 K, 88 8raffiaBmiBfi ™5ST Bar-Han University, Israel IMENTS AND Bar-Han Physics Laboratory \^^"-^ ^ ^ World Scientific \ * W . f * S l V • U'), where a is the absolute value of the field, and b is the rotation angle. The graph y(x) clearly shows the angular dependence of the field. The magnetic field produced by a bar magnet is measured as a function of its orientation (Fig. 5). The magnet is mounted on the axle of the Rotary motion sensor. The results are presented in polar coordinates. The graph is just similar to that for the two coils. This similarity supports the concept that every magnetic field is caused by electric currents. Basano et al. (1988) have shown, however, that the magnetic fields generated by a bar magnet and by a solenoid of the same shape and dimension are similar but not equal. 35 1.9. Magnetic field measurements data-acquisition system input A inputs 1, 2 magnetic field sensor Helmholtz coils rotary motion Fig. 4. Diagram of the setup for measuring the angular dependence of the magnetic field produced by two adjacent coils, and results obtained (in gauss). i f data-acquisition system input A ~to- -4. inputs 1, 2 bar magnet ' ' I ' ! • -e j magnetic field sensor !V 4 | rotary motion sensor .' \. . . Fig. 5. Diagram of the setup for measuring the angular dependence of the field of a bar magnet and results obtained (in gauss). 36 1.10. Magnetic force 1-10- Magnetic force The experiment (Kraftmakher 2004a) shows that (i) the magnetic force is proportional to the current flowing through the conductor, and (ii) the direction of the force depends upon the relative orientation of the field and the conductor. data-acquisition system input A I input B 0.1 n force w / sensor / /, n L r* DC supply force sensor conductor P / ^ r a s H f permanent I W ^ B magnet aluminum plate "*"* conductor™ Arrange merit for wweighing currents;arry HgCCmduetor placed inside thegap»of a permanen t i riagnet. permanent magnet — Additional equipment: Force sensor, Voltage sensor, permanent magnet, variable DC supply (up to 3.5 A), resistor (1 CI, 10 W), aluminum plate. 37 1.10. Magnetic force Lorentz force The force acting on an electric charge contains two components, the electric force and the magnetic force. While the elect