Array ( [0] => Array ( [title] => L39A [link] => https://www.youtube.com/embed/8G9t3uAl0Gw ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第39講|Lecture 7 Electrodynamics|7_2C 7_2_4 Energy in Magnetic Field