Nam ch\u00e2m l\u00e0 \u0111\u00e1 h\u00fat s\u1eaft, b\u1ea1n \u0111\u00e3 ch\u01a1i v\u1edbi n\u00f3 l\u1ea7n n\u00e0o ch\u01b0a? D\u00f9ng nam ch\u00e2m c\u00f3 th\u1ec3 h\u00fat \u0111\u01b0\u1ee3c \u0111\u1ed3 v\u1eadt l\u00e0m b\u1eb1ng s\u1eaft nh\u01b0 \u0111inh, kim v.v., r\u1ea5t l\u00e0 th\u00fa v\u1ecb.<\/p>\n\n\n\n
V\u00ec sao nam ch\u00e2m c\u00f3 th\u1ec3 h\u00fat \u0111\u01b0\u1ee3c s\u1eaft nh\u1ec9? C\u00e1i \u0111\u00f3 ph\u1ea3i gi\u1ea3i th\u00edch t\u1eeb k\u1ebft c\u1ea5u ph\u00e2n t\u1eed c\u1ee7a v\u1eadt ch\u1ea5t tr\u1edf \u0111i.<\/p>\n\n\n\n
M\u1ecdi v\u1eadt ch\u1ea5t \u0111\u1ec1u do ph\u00e2n t\u1eed c\u1ea5u th\u00e0nh c\u1ea3. Ph\u00e2n t\u1eed do nguy\u00ean t\u1eed h\u1ee3p th\u00e0nh, nguy\u00ean t\u1eed l\u1ea1i do h\u1ea1t nh\u00e2n nguy\u00ean t\u1eed v\u00e0 electron h\u1ee3p th\u00e0nh. Electron kh\u00f4ng ng\u1eebng t\u1ef1 quay trong nguy\u00ean t\u1eed v\u00e0 quay xung quanh h\u1ea1t nh\u00e2n nguy\u00ean t\u1eed. Hai lo\u1ea1i chuy\u1ec3n \u0111\u1ed9ng \u0111\u00f3 c\u1ee7a electron \u0111\u1ec1u c\u00f3 th\u1ec3 sinh ra t\u1eeb t\u00ednh. Song, trong \u0111\u1ea1i \u0111a s\u1ed1 v\u1eadt ch\u1ea5t, h\u01b0\u1edbng chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a electron kh\u00f4ng gi\u1ed1ng nhau, l\u1ed9n x\u1ed9n, lung tung. \u0110i\u1ec1u \u0111\u00f3 l\u00e0m cho hi\u1ec7u \u1ee9ng t\u1eeb t\u00ednh c\u1ee7a n\u1ed9i b\u1ed9 v\u1eadt ch\u1ea5t tri\u1ec7t ti\u00eau l\u1eabn nhau. V\u00ec v\u1eady, trong t\u00ecnh tr\u1ea1ng b\u00ecnh th\u01b0\u1eddng, ph\u1ea7n l\u1edbn c\u00e1c v\u1eadt ch\u1ea5t kh\u00f4ng th\u1ec3 hi\u1ec7n t\u1eeb t\u00ednh.<\/p>\n\n\n\n
C\u00f2n nam ch\u00e2m th\u00ec kh\u00f4ng ph\u1ea3i nh\u01b0 v\u1eady. N\u00f3i chung nam ch\u00e2m do nguy\u00ean li\u1ec7u s\u1eaft t\u1eeb nh\u01b0 s\u1eaft, coban, niken ho\u1eb7c ferit v.v. l\u00e0m th\u00e0nh. T\u1eeb t\u00ednh c\u1ee7a nam ch\u00e2m b\u1eaft ngu\u1ed3n ch\u1ee7 y\u1ebfu t\u1eeb s\u1ef1 t\u1ef1 quay c\u1ee7a electron. Trong ch\u1ea5t s\u1eaft t\u1eeb, s\u1ef1 t\u1ef1 quay c\u1ee7a electron c\u00f3 th\u1ec3 t\u1ef1 ph\u00e1t s\u1eafp x\u1ebfp \u1edf ph\u1ea1m vi nh\u1ecf, t\u1ee9c l\u00e0 m\u1ecdi electron trong nguy\u00ean t\u1eed \u1edf trong ph\u1ea1m vi nh\u1ecf \u0111\u00f3 \u0111\u1ec1u gi\u1eef \u0111\u01b0\u1ee3c h\u01b0\u1edbng t\u1ef1 quay nh\u01b0 nhau, h\u00ecnh th\u00e0nh m\u1ed9t v\u00f9ng t\u1eeb ho\u00e1 nh\u1ecf t\u1ef1 ph\u00e1t. Lo\u1ea1i v\u00f9ng t\u1eeb ho\u00e1 t\u1ef1 ph\u00e1t n\u00e0y g\u1ecdi l\u00e0 mi\u1ec1n t\u1eeb (\u0111\u00f4men t\u1eeb). K\u00edch th\u01b0\u1edbc c\u1ee7a mi\u1ec1n t\u1eeb kh\u00f4ng gi\u1ed1ng nhau. T\u00f3m l\u1ea1i, m\u1ed7i mi\u1ec1n t\u1eeb chi\u1ebfm th\u1ec3 t\u00edch kho\u1ea3ng 109 cm3, ch\u1ee9a kho\u1ea3ng 1015 nguy\u00ean t\u1eed. V\u00ec h\u01b0\u1edbng t\u1eeb t\u00ednh c\u1ee7a t\u1ea5t c\u1ea3 nguy\u00ean t\u1eed trong m\u1ed9t mi\u1ec1n t\u1eeb \u0111\u1ec1u \u0111\u1ed3ng nh\u1ea5t, k\u1ebft qu\u1ea3 c\u1ee7a s\u1ef1 x\u1ebfp ch\u1ed3ng l\u00e0 t\u1eeb t\u00ednh t\u0103ng c\u01b0\u1eddng l\u1eabn nhau. M\u1ed9t mi\u1ec1n t\u1eeb t\u01b0\u01a1ng \u0111\u01b0\u01a1ng v\u1edbi m\u1ed9t “nam ch\u00e2m nh\u1ecf”, c\u1ee5c nam ch\u00e2m l\u00e0 do m\u1ed9t l\u01b0\u1ee3ng l\u1edbn “nam ch\u00e2m nh\u1ecf” nh\u01b0 v\u1eady h\u1ee3p th\u00e0nh.<\/p>\n\n\n\n
Tr\u01b0\u1edbc khi t\u1eeb ho\u00e1, h\u01b0\u1edbng t\u1eeb t\u00ednh c\u1ee7a m\u1ecdi mi\u1ec1n t\u1eeb trong n\u1ed9i b\u1ed9 nguy\u00ean li\u1ec7u s\u1eaft t\u1eeb kh\u00f4ng gi\u1ed1ng nhau, kh\u00f4ng ph\u1ed1i h\u1ee3p v\u1edbi nhau, h\u01b0\u1edbng n\u00e0o c\u0169ng c\u00f3. K\u1ebft qu\u1ea3 l\u00e0 c\u00e1c t\u1eeb tr\u01b0\u1eddng kh\u00e1c h\u01b0\u1edbng tri\u1ec7t ti\u00eau l\u1eabn nhau, \u0111\u1ed1i v\u1edbi b\u00ean ngo\u00e0i v\u1eabn l\u00e0 kh\u00f4ng th\u1ec3 hi\u1ec7n t\u1eeb t\u00ednh. Tuy nhi\u00ean, sau khi \u0111\u1eb7t v\u00e0o t\u1eeb tr\u01b0\u1eddng m\u1ea1nh b\u00ean ngo\u00e0i, ch\u00fang li\u1ec1n s\u1eafp x\u1ebfp l\u1ea1i theo h\u01b0\u1edbng c\u1ee7a t\u1eeb tr\u01b0\u1eddng. Ch\u00fang ta n\u00f3i ch\u1ea5t s\u1eaft t\u1eeb \u0111\u00e3 b\u1ecb t\u1eeb ho\u00e1. N\u00f3 li\u1ec1n bi\u1ebfn th\u00e0nh m\u1ed9t c\u1ee5c nam ch\u00e2m. Nh\u01b0ng, \u1edf nh\u1eefng v\u1eadt li\u1ec7u kh\u00e1c khi \u0111\u1eb7t trong t\u1eeb tr\u01b0\u1eddng, c\u00e1c electron trong nguy\u00ean t\u1eed kh\u00f4ng tu\u00e2n “m\u1ec7nh l\u1ec7nh” m\u00e0 “x\u1ebfp h\u00e0ng ngay ng\u1eafn”, v\u1eabn chuy\u1ec3n \u0111\u1ed9ng h\u1ed7n \u0111\u1ed9n. \u0110\u00f3 l\u00e0 c\u00e1c v\u1eadt li\u1ec7u phi t\u1eeb t\u00ednh nh\u01b0 \u0111\u1ed3ng, nh\u00f4m, ch\u00ec v.v. \u1ede \u0111\u00f3 c\u00e1c electron l\u1ea1i gi\u1ed1ng nh\u01b0 m\u1ed9t \u0111\u00e1m tr\u1ebb con kh\u00f4ng v\u00e2ng l\u1eddi, cho d\u00f9 c\u00f3 \u0111\u1eb7t v\u00e0o m\u1ed9t t\u1eeb tr\u01b0\u1eddng b\u00ean ngo\u00e0i m\u1ea1nh h\u01a1n n\u1eefa, ch\u00fang v\u1eabn v\u1eadn \u0111\u1ed9ng l\u1ed9n x\u1ed9n theo \u00fd m\u00ecnh. Cho n\u00ean nh\u1eefng v\u1eadt li\u1ec7u \u1ea5y kh\u00f4ng th\u1ec3 t\u1eeb ho\u00e1, c\u0169ng t\u1ee9c l\u00e0 kh\u00f4ng c\u00f3 t\u1eeb t\u00ednh.<\/p>\n\n\n\n
S\u1edf d\u0129 nam ch\u00e2m h\u00fat \u0111\u01b0\u1ee3c s\u1eaft l\u00e0 v\u00ec nam ch\u00e2m c\u00f3 t\u1eeb t\u00ednh. Khi \u1edf g\u1ea7n s\u1eaft, t\u1eeb tr\u01b0\u1eddng c\u1ee7a nam ch\u00e2m li\u1ec1n l\u00e0m cho c\u1ee5c s\u1eaft b\u1ecb t\u1eeb ho\u00e1. Gi\u1eefa c\u00e1c c\u1ef1c kh\u00e1c nhau c\u1ee7a nam ch\u00e2m v\u00e0 c\u1ee5c s\u1eaft sinh ra l\u1ef1c h\u00fat, c\u1ee5c s\u1eaft li\u1ec1n “d\u00ednh” ch\u1eb7t v\u00e0o nam ch\u00e2m. Song c\u00e1c kim lo\u1ea1i nh\u01b0 \u0111\u1ed3ng, nh\u00f4m, ch\u00ec v.v. kh\u00f4ng th\u1ec3 b\u1ecb t\u1eeb tr\u01b0\u1eddng c\u1ee7a nam ch\u00e2m t\u1eeb ho\u00e1, kh\u00f4ng sinh ra \u0111\u01b0\u1ee3c t\u1eeb t\u00ednh, v\u00ec v\u1eady nam ch\u00e2m \u0111\u00e0nh b\u1ea5t l\u1ef1c \u0111\u1ed1i v\u1edbi ch\u00fang.<\/p>\n\n\n\n
Nam ch\u00e2m v\u0129nh c\u1eedu m\u00e0 ch\u00fang ta th\u01b0\u1eddng g\u1eb7p c\u00f3 hai lo\u1ea1i: nam ch\u00e2m nh\u00e2n t\u1ea1o v\u00e0 nam ch\u00e2m thi\u00ean nhi\u00ean. Nam ch\u00e2m nh\u00e2n t\u1ea1o \u0111\u01b0\u1ee3c ch\u1ebf t\u1ea1o b\u1eb1ng c\u00e1ch \u0111\u1eb7t nguy\u00ean li\u1ec7u c\u00f3 t\u00ednh s\u1eaft t\u1eeb v\u00e0o trong t\u1eeb tr\u01b0\u1eddng, l\u00e0m cho n\u00f3 t\u1eeb ho\u00e1. Sau khi r\u00fat b\u1ecf t\u1eeb tr\u01b0\u1eddng b\u00ean ngo\u00e0i, \u0111i\u1ec7n t\u1eed trong nguy\u00ean li\u1ec7u c\u00f3 t\u00ednh s\u1eaft t\u1eeb v\u1eabn duy tr\u00ec “h\u00e0ng l\u1ed1i ch\u1ec9nh th\u1ec3”, th\u1ec3 hi\u1ec7n t\u1eeb t\u00ednh r\u1ea5t m\u1ea1nh \u0111\u1ed1i v\u1edbi b\u00ean ngo\u00e0i. C\u00f2n nam ch\u00e2m thi\u00ean nhi\u00ean l\u00e0 m\u1ed9t lo\u1ea1i \u0111\u00e1 qu\u1eb7ng s\u1eaft trong thi\u00ean nhi\u00ean, d\u01b0\u1edbi t\u00e1c \u0111\u1ed9ng t\u1eeb ho\u00e1 c\u1ee7a t\u1eeb tr\u01b0\u1eddng Tr\u00e1i \u0110\u1ea5t, n\u00f3 c\u00f3 mang t\u1eeb t\u00ednh v\u0129nh c\u1eedu.<\/p>\n\n\n\n
T\u1eeb kho\u00e1: Nam ch\u00e2m; Mi\u1ec1n t\u1eeb; T\u1eeb ho\u00e1; Nam ch\u00e2m nh\u00e2n t\u1ea1o; Nam ch\u00e2m<\/p>\n\n\n\n
<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"
Nam ch\u00e2m l\u00e0 \u0111\u00e1 h\u00fat s\u1eaft, b\u1ea1n \u0111\u00e3 ch\u01a1i v\u1edbi n\u00f3 l\u1ea7n n\u00e0o ch\u01b0a? D\u00f9ng nam ch\u00e2m c\u00f3 th\u1ec3 h\u00fat \u0111\u01b0\u1ee3c \u0111\u1ed3 v\u1eadt l\u00e0m b\u1eb1ng s\u1eaft nh\u01b0 \u0111inh, kim v.v., r\u1ea5t l\u00e0 th\u00fa v\u1ecb. V\u00ec sao nam ch\u00e2m c\u00f3 th\u1ec3 h\u00fat \u0111\u01b0\u1ee3c s\u1eaft nh\u1ec9? C\u00e1i \u0111\u00f3 ph\u1ea3i gi\u1ea3i th\u00edch t\u1eeb k\u1ebft c\u1ea5u ph\u00e2n t\u1eed c\u1ee7a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[15,7],"tags":[],"class_list":["post-5710","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-vat-ly"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/5710","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=5710"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/5710\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=5710"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=5710"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=5710"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}