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Phuocduy0311
2 năm trước
Một tia sáng chiếu tới một gương phẳng nằm ngang với góc i=30độ. Nếu tia tới cố định, để có tia phản xạ nằm ngang thì phải quay gương 1 góc nhỏ nhất là A. 15 B. 30 C. 45 D. 75
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