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ฟิสิกส์โอลิมปิก วิทยาศาสตร์โอลิมปิก ข้อสอบแข่งขัน ข้อสอบชิงทุน => GRE - Physics => Topic started by: conantee on December 08, 2010, 03:45:47 AM



Title: GR9677.067
Post by: conantee on December 08, 2010, 03:45:47 AM
67. A black hole is an object whose gravitational field is so strong that even light cannot escape. To what approximate radius would Earth (mass = 5.98 \times 10^{24} kilograms) have to be compressed in order to become a black hole?
(A) 1 \mbox{ nm}
(B) 1 \mbox{ \mu m}
(C) 1 \mbox{ cm}
(D) 100 \mbox{ m}
(E) 10 \mbox{ km}