Ch\u01b0\u01a1ng 7 – B\u00e0i 46: Hi\u1ec7n t\u01b0\u1ee3ng quang \u0111i\u1ec7n trong. Quang \u0111i\u1ec7n tr\u1edf v\u00e0 pin quang \u0111i\u1ec7n<\/a><\/blockquote><\/iframe>