Có hai quả cầu nhôm nhẹ A và B được treo bởi hai s...
Câu hỏi: Có hai quả cầu nhôm nhẹ A và B được treo bởi hai sợi tơ mảnh tại cùng một điểm, quả cầu A nhiễm điện (-) và chúng đẩy nhau như hình vẽ. Quả cầu B có nhiễm điện không? Nếu có thì nhiễm điện loại gì?![](data:image/png;base64,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)
A Không nhiễm điện
B Quả cầu B nhiễm điện dương
C Quả cầu B nhiễm điện âm
D Không xác định được
Câu hỏi trên thuộc đề trắc nghiệm
Kiểm tra học kỳ II Vật Lí 7 (Đề số 2)