Question

9£®Á½¸ö´Å¸ÐӦǿ¶È¾ùΪBµÄÔÈÇ¿´Å³¡ÇøÓò¢ñ¡¢¢ó£¬·½ÏòÈçͼËùʾ£¬Á½¸öÇøÓòÖмäΪ¿íΪsµÄÎ޴ų¡ÇøÓò¢ò£¬ÓÐÒ»±ß³¤ÎªL£¨L£¾s£©¡¢µç×èΪRµÄ¾ùÔÈÕý·½ÐνðÊôÏß¿òabcdÖÃÓÚ¢ñÇøÓò£¬ab±ßÓë´Å³¡±ß½çƽÐУ¬ÏÖÀ­×ŽðÊôÏß¿òÒÔËÙ¶ÈvÏòÓÒÔÈËÙÔ˶¯£¬Ôò£¨¡¡¡¡£©

• A£® µ±ab±ß¸Õ½øÈë´Å³¡ÇøÓò¢óʱ£¬Í¨¹ýab±ßµÄµçÁ÷´óСΪ$\frac{2BLv}{R}$£¬·½ÏòΪa¡úb
• B£® µ±ab±ß¸Õ½øÈëÖмäÎ޴ų¡ÇøÓò¢òʱ£¬a¡¢bÁ½µã¼äµÄµçѹΪ$\frac{3BLv}{4}$
• C£® ´Ócd±ß¸Õ½øÈë¢òÇøÓòµ½¸Õ½øÈë¢óÇøÓòµÄ¹ý³ÌÖУ¬»Ø·ÖвúÉúµÄ½¹¶úÈÈΪ$\frac{{B}^{2}{L}^{2}v}{R}$£¨L-s£©
• D£® ´Óab±ß¸Õ½øÈë¢òÇøÓòµ½ÍêÈ«À­Èë¢óÇøÓò¹ý³ÌÖУ¬À­Á¦Ëù×öµÄ¹¦Îª$\frac{2{B}^{2}{L}^{2}v}{R}$£¨2L-s£©

Answer 1

·ÖÎö ½ðÊô¿ò´ÓIÇøÓòÍêÈ«À­ÈëIIIÇøÓò¹ý³Ì¿ÉÒÔ·Ö³ÉÈý¶ÎÑо¿£ºµÚÒ»¶ÎabÔÚ¢òÇøÔ˶¯£¬µÚ¶þ¶ÎabÔÚ¢ó£¬cdÔÚ¢ñÇøÔ˶¯£¬µÚÈý¶ÎcdÔÚ¢òÇøÔ˶¯£®¸ù¾ÝÅ·Ä·¶¨ÂÉ¡¢°²ÅàÁ¦µÈ֪ʶÇó½â£®

½â´ð ½â£ºA¡¢µ±ab±ß¸Õ½øÈë´Å³¡ÇøÓòIIIʱ£¬Í¨¹ýab±ßµÄµçÁ÷´óС£ºI¡ä=$\frac{2BLv}{R}$£¬¸ù¾ÝÓÒÊÖ¶¨Ôò¿ÉÖª£¬¸ÐÓ¦µçÁ÷·½Ïòa¡úb£®¹ÊAÕýÈ·£®
B¡¢µ±ab±ß½øÈëÖÐÑëÎ޴ų¡ÇøÓòIIʱ£¬ÔÚcd±ßÉÏÇиî´Å¸ÐÏß²úÉúµÄµç¶¯ÊÆ£ºE=BLv£¬µç·ÖеĵçÁ÷£ºI=$\frac{E}{R}$£¬abÁ½µã¼äµçѹU=I•$\frac{R}{4}$=$\frac{1}{4}$E=$\frac{BLv}{4}$£¬¹ÊB´íÎó£®
C¡¢´Ócd±ß¸Õ½øÈë¢òÇøÓòµ½¸Õ½øÈë¢óÇøÓòµÄ¹ý³ÌÖУ¬»Ø·ÖиÐÓ¦µçÁ÷´óСI=$\frac{BLv}{R}$£¬°²ÅàÁ¦×öµÄ¹¦£¬¼´Îª²úÉúµÄ½¹¶úÈÈ£¬ÔòΪQ=W=$\frac{{B}^{2}{L}^{2}v}{R}$s£¬¹ÊC´íÎó£®
D¡¢½ðÊô¿ò´Óab±ß¸Õ½øÈë¢òÇøÓòµ½ÍêÈ«À­ÈëIIIÇøÓò¹ý³ÌÖУ¬ab±ßÓëcd±ßÊܵ½µÄ°²ÅàÁ¦¾ùÏò×ó£¬
´óС£ºF _A=BI¡äL£¬ËùÒÔÀ­Á¦´óС£ºF=2F_A=$\frac{4{B}^{2}{L}^{2}v}{R}$
À­Á¦Ëù×ö¹¦W=$\frac{{B}^{2}{L}^{2}v}{R}$•S+$\frac{£¨2BLv£©^{2}}{R}•\frac{L-S}{v}$+$\frac{{B}^{2}{L}^{2}v}{R}$•S=$\frac{2{B}^{2}{L}^{2}v}{R}$£¨2L-S£©£¬¹ÊDÕýÈ·£®
¹ÊÑ¡£ºAD£®

µãÆÀ ±¾ÌâҪעÒâµÄÊǵ±ab±ß¸Õ½øÈë´Å³¡ÇøÓòIIIʱ£¬ab¡¢cd¶¼Çиî´Å¸ÐÏß²úÉúÁ½¸ö¸ÐÓ¦µç¶¯ÊÆ£¬¶øÇÒ´®Áª£¬µç·ÖеÄ×ܵ綯ÊÆΪE_×Ü=2E=2BLv£®