Question

20£®Ð¡ÑôͬѧÔڿƼ¼ÔÂÖÆ×÷ÁËÒ»¸ö¶àµµÎ»µçÈÈÆ÷Ä£ÐÍ£®ÎªÁË·ÖÎö½ÓÈëµç·µÄµç×è¶ÔµçÈÈÆ÷µÄµç¹¦ÂʵÄÓ°Ï죬Ëû½«µç±í½ÓÈëµç·ÖУ¬Æäµç·ÈçͼËùʾ£¬µçÔ´Á½¶Ëµçѹ²»±ä£¬R₁=30¦¸£®µ±¿ª¹ØS±ÕºÏ£¬S₁¡¢S₂¶Ï¿ªÊ±£¬µçѹ±íʾÊýΪU₁£¬µ±S¡¢S₁¡¢S₂¶¼±ÕºÏʱ£¬µçѹ±íʾÊýΪU₂£¬ÒÑÖªU₁£ºU₂=3£º8£»Á½ÖÖ״̬ʱ£¬R₂ÏûºÄµÄ¹¦ÂÊ×î´óÖµP_´óºÍ×îСֵP_С֮±ÈΪ4£º1£»R₃µÄ×îС¹¦ÂÊΪ0.9W£®ÇëÄã°ïСÑôÍê³ÉÏÂÁÐÎÊÌ⣮
£¨1£©»­³öÉÏÊöÁ½¸ö״̬µÄµÈЧµç·ͼ£®
£¨2£©¼ÆËãµç×èR₂µÄ×èÖµ£®
£¨3£©¼ÆËãµçÔ´Á½¶ËµÄµçѹ£®
£¨4£©¼ÆËãÕâ¸öµçÈÈÆ÷Ä£ÐÍ×î´óµµÎ»ºÍ×îСµµÎ»¶ÔÓ¦µÄ¹¦ÂÊ·Ö±ðÊǶàÉÙ£¿

Answer 1

·ÖÎö £¨1£©µ±¿ª¹ØS±ÕºÏ£¬S₁¡¢S₂¶Ï¿ªÊ±£¬Èýµç×è´®Áª£¬µçѹ±í²âR1Á½¶ËµÄµçѹ£»µ±S¡¢S₁¡¢S₂¶¼±ÕºÏʱ£¬Èýµç×è²¢Áª£¬µçѹ±í²âµçÔ´µÄµçѹ£¬µçÁ÷±í²âR₁ºÍR₂֧·µÄµçÁ÷Ö®ºÍ£¬¾Ý´Ë»­³öµÈЧµç·ͼ£»
£¨2£©¸ù¾Ý²¢Áªµç·µÄµçѹÌصã¿É֪ͼ2Öеçѹ±íµÄʾÊýºÍµçÔ´µÄµçѹÏàµÈ£¬¸ù¾Ý´®Áªµç·µÄµçÁ÷ÌصãºÍÅ·Ä·¶¨Âɱíʾ³öU₁£ºU₂=3£º8¼´¿ÉÇó³öͼ1µÄ×ܵç×裬¸ù¾ÝÅ·Ä·¶¨ÂÉÇó³öͼ1Öеç·ÖеĵçÁ÷£¬¸ù¾ÝP=IR₂±íʾ³öR₂µÄ×îСµç¹¦ÂÊ£¬¸ù¾ÝP=$\frac{{U}^{2}}{R}$±íʾ³öR₂µÄ×î´ó×ܹ¦ÂÊ£¬ÀûÓÃR₂ÏûºÄµÄ¹¦ÂÊ×î´óÖµP_´óºÍ×îСֵP_С֮±ÈΪ4£º1¼´¿ÉÇó³öR₂µÄ×èÖµ£»
£¨3£©¸ù¾Ý´®Áªµç·µÄµçѹÌصãÇó³öͼ1ÖÐR₃µÄ×èÖµ£¬¸ù¾ÝP=I²R±íʾ³öR₃µÄ×îС¹¦Âʼ´¿ÉÇó³öµçÔ´µÄµçѹ£»
£¨4£©Í¼1ÖУ¬µç·ÖеĵçÁ÷×îС£¬µç·µÄ×ܹ¦ÂÊ×îС£¬¸ù¾ÝP=$\frac{{U}^{2}}{R}$Çó³öµçÈÈÆ÷µÄ×îС×ܹ¦ÂÊ£»Í¼2ÖУ¬Èýµç×èÁ½¶ËµÄµçѹ×î´ó£¬µç·µÄ×ܹ¦ÂÊ×î´ó£¬¸ù¾ÝP=$\frac{{U}^{2}}{R}$Çó³öµçÈÈÆ÷µÄ×î´ð×ܹ¦ÂÊ£®

½â´ð ½â£º£¨1£©µ±¿ª¹ØS±ÕºÏ£¬S₁¡¢S₂¶Ï¿ªÊ±£¬µÈЧµç·ͼÈçͼ1Ëùʾ£»µ±S¡¢S₁¡¢S₂¶¼±ÕºÏʱ£¬µÈЧµç·ͼÈçͼ2Ëùʾ£º

£¨2£©Òò²¢Áªµç·Öи÷֧·Á½¶ËµÄµçѹÏàµÈ£¬
ËùÒÔ£¬ÓÉͼ2¿ÉÖª£¬µçѹ±íµÄʾÊýU₂=U£¬
ͼ1ÖУ¬Òò´®Áªµç·Öи÷´¦µÄµçÁ÷ÏàµÈ£¬
ËùÒÔ£¬$\frac{{U}_{1}}{{U}_{2}}$=$\frac{{U}_{1}}{U}$=$\frac{I{R}_{1}}{I{R}_{×Ü}}$=$\frac{{R}_{1}}{{R}_{×Ü}}$=$\frac{30¦¸}{{R}_{×Ü}}$=$\frac{3}{8}$£¬
½âµÃ£ºR_×Ü=80¦¸£¬
µç·ÖеĵçÁ÷I=$\frac{U}{{R}_{×Ü}}$=$\frac{U}{80¦¸}$£¬
ͼ1Öеç·ÖеĵçÁ÷×îС£¬R₂ºÍR₃µÄµç¹¦ÂÊ×îС£¬ÔòP_С=I²R₂=£¨$\frac{U}{{R}_{×Ü}}$£©²R₂=$\frac{{U}^{2}{R}_{2}}{{{R}_{×Ü}}^{2}}$£¬
ͼ2ÖÐR₂Á½¶ËµÄµçѹ×î´ó£¬¹¦ÂÊ×î´ó£¬ÔòP_´ó=$\frac{{U}^{2}}{{R}_{2}}$£¬
ÒòP_´ó£ºP_С=4£º1£¬
ËùÒÔ£¬$\frac{{P}_{´ó}}{{P}_{С}}$=$\frac{\frac{{U}^{2}}{{R}_{2}}}{\frac{{U}^{2}{R}_{2}}{{{R}_{×Ü}}^{2}}}$=£¨$\frac{{R}_{×Ü}}{{R}_{2}}$£©²=$\frac{4}{1}$£¬
½âµÃ£ºR₂=$\frac{1}{2}$R_×Ü=$\frac{1}{2}$¡Á80¦¸=40¦¸£»
£¨3£©Í¼1ÖУ¬Òò´®Áªµç·ÖÐ×ܵçѹµÈÓÚ¸÷·Öµçѹ֮ºÍ£¬
ËùÒÔ£¬R₃µÄ×èÖµ£º
R₃=R_×Ü-R₁-R₂=80¦¸-30¦¸-40¦¸=10¦¸£¬
R₃µÄ×îС¹¦ÂÊ£º
P₃=I²R₃=£¨$\frac{U}{{R}_{×Ü}}$£©²R₃=£¨$\frac{U}{80¦¸}$£©²¡Á10¦¸=0.9W£¬
½âµÃ£ºU=24V£»
£¨4£©Í¼1ÖУ¬µç·ÖеĵçÁ÷×îС£¬µç·µÄ×ܹ¦ÂÊ×îС£¬
ÔòP_×ÜС=$\frac{{U}^{2}}{{R}_{×Ü}}$=$\frac{£¨24V£©^{2}}{80¦¸}$=7.2W£¬
ͼ2ÖУ¬Èýµç×èÁ½¶ËµÄµçѹ×î´ó£¬µç·µÄ×ܹ¦ÂÊ×î´ó£¬
ÔòP_×Ü´ó=$\frac{{U}^{2}}{{R}_{1}}$+$\frac{{U}^{2}}{{R}_{2}}$+$\frac{{U}^{2}}{{R}_{3}}$=$\frac{£¨24V£©^{2}}{30¦¸}$+$\frac{£¨24V£©^{2}}{40¦¸}$+$\frac{£¨24V£©^{2}}{10¦¸}$=91.2W£®
´ð£º£¨1£©ÉÏÊöÁ½¸ö״̬µÄµÈЧµç·ͼÈçÉÏͼËùʾ£»
£¨2£©µç×èR₂µÄ×èֵΪ40¦¸£»
£¨3£©µçÔ´Á½¶ËµÄµçѹΪ24V£»
£¨4£©Õâ¸öµçÈÈÆ÷Ä£ÐÍ×î´óµµÎ»ºÍ×îСµµÎ»¶ÔÓ¦µÄ¹¦ÂÊ·Ö±ðΪ91.2W¡¢7.2W£®

µãÆÀ ±¾Ì⿼²éÁË´®²¢Áªµç·µÄÌصãºÍÅ·Ä·¶¨ÂÉ¡¢µç¹¦Âʹ«Ê½µÄÓ¦Ó㬻­³öÁ½ÖÖÇé¿öϵĵÈЧµç·ͼÊǽâÌâµÄ»ù´¡£¬ÀûÓÃËù¸øµÄµçѹ¹ØϵºÍ¹¦ÂʹØϵÊǹؼü£®