Question

8£®ÈçͼËùʾ£¬Í¬Ò»Æ½ÃæÄÚÓÐÁ½¸ùƽÐеÄÎÞÏÞ³¤Ö±µ¼Ïß1ºÍ2£¬Í¨ÓдóСÏàµÈ¡¢·½ÏòÏà·´µÄµçÁ÷£¬a¡¢bÁ½µãÓëÁ½µ¼Ïß¹²Ã棬aµãÔÚÁ½µ¼ÏßµÄÖмäÇÒÓëÁ½µ¼ÏߵľàÀë¾ùΪr£¬bµãÔÚµ¼Ïß2ÓҲ࣬Óëµ¼Ïß2µÄ¾àÀëҲΪr£®ÏÖ²âµÃaµãµÄ´Å¸ÐӦǿ¶È´óСΪB₀£¬ÒÑÖª¾àÒ»ÎÞÏÞ³¤Ö±µ¼Ïßd´¦µÄ´Å¸ÐӦǿ¶È´óСB=$\frac{kI}{d}$£¬ÆäÖÐkΪ³£Á¿£¬IΪÎÞÏÞ³¤Ö±µ¼ÏߵĵçÁ÷´óС£¬ÏÂÁÐ˵·¨ÕýÈ·µÄÊÇ£¨¡¡¡¡£©

• A£® bµãµÄ´Å¸ÐӦǿ¶È´óСΪ$\frac{{B}_{0}}{4}$
• B£® ÈôÈ¥µôµ¼Ïß2£¬bµãµÄ´Å¸ÐӦǿ¶È´óСΪ$\frac{{B}_{0}}{6}$
• C£® Èô½«µ¼Ïß1ÖеçÁ÷´óС±äΪԭÀ´µÄ2±¶£¬bµãµÄ´Å¸ÐӦǿ¶ÈΪ0
• D£® ÈôÈ¥µôµ¼Ïß2£¬ÔÙ½«µ¼Ïß1ÖеçÁ÷´óС±äΪԭÀ´µÄ2±¶£¬aµãµÄ´Å¸ÐӦǿ¶È´óСÈÔΪB₀

Answer 1

·ÖÎö ¸ù¾ÝÓÒÊÖÂÝÐý¶¨ÔòµÃ³öÖ±µ¼ÏßÖÜΧµÄ´Å³¡·½Ïò£¬½áºÏ³¡Ç¿µÄµþ¼Ó£¬¸ù¾ÝB=K$\frac{I}{d}$ Çó³öaµãµÄ³¡Ç¿£¬

½â´ð ½â£ºA¡¢ÉèÁ½µ¼Ïß¼ä¾àΪr£¬¸ù¾ÝÓÒÊÖÂÝÐý¶¨ÔòÖª£¬1µ¼ÏßÔÚaµãµÄ³¡Ç¿·½Ïò´¹Ö±Ö½ÃæÏòÀ2µ¼ÏßÔÚaµãµÄ³¡Ç¿·½Ïò´¹Ö±Ö½ÃæÏòÀ¸ù¾Ý³¡Ç¿µÄµþ¼ÓÓУº
B₀=2k$\frac{I}{d}$=$\frac{2KI}{r}$£»
1µ¼ÏßÔÚbµãµÄ³¡Ç¿·½Ïò´¹Ö±Ö½ÃæÏòÀ2µ¼ÏßÔÚbµãµÄ³¡Ç¿·½Ïò´¹Ö±Ö½ÃæÏòÍ⣬¸ù¾Ý³¡Ç¿µÄµþ¼ÓÖª£¬bµãµÄ´Å¸ÐӦǿ¶ÈΪ£º
B_b=k$\frac{I}{3r}$-k$\frac{I}{r}$=-k $\frac{2I}{3r}$=-$\frac{{B}_{0}}{3}$£®¹ÊA´íÎó
B¡¢ÈôÈ¥µôµ¼Ïß2£¬bµãµÄ´Å¸ÐӦǿ¶È´óСΪB_b=k$\frac{I}{3r}$=$\frac{{B}_{0}}{6}$£¬¹ÊBÕýÈ·
C¡¢Èô½«µ¼Ïß1ÖеçÁ÷´óС±äΪԭÀ´µÄ2±¶£¬bµãµÄ´Å¸ÐӦǿ¶ÈΪB_b=k$\frac{2I}{3r}$-k$\frac{I}{r}$=-k $\frac{I}{3r}$=-$\frac{{B}_{0}}{6}$¹ÊC´íÎó
D¡¢ÈôÈ¥µôµ¼Ïß2£¬ÔÙ½«µ¼Ïß1ÖеçÁ÷´óС±äΪԭÀ´µÄ2±¶£¬aµãµÄ´Å¸ÐӦǿ¶È´óСÈÔΪB=k$\frac{2I}{3r}$=B₀£¬¹ÊDÕýÈ·
¹ÊÑ¡£ºBD

µãÆÀ ±¾Ì⿼²éÁ˳¡Ç¿µÄµþ¼ÓÒÔ¼°°²ÅàÁ¦µÄ´óС¹«Ê½ÔËÓã¬ÕÆÎÕÓÒÊÖÂÝÐý¶¨ÔòÅжϵçÁ÷ÖÜΧ´Å³¡µÄ·½ÏòÊǽâ¾ö±¾ÌâµÄ¹Ø¼ü