Đề thi vật lí 9 giữa kì II

Họ và tên : .............................................................................. Lớp : .......... : SBD
đề thi khảo sát giữa kỳ II năm học 2011-2012
Môn :Vật lý Thời gian : 60 phút

Bài 1:Nêu đặc điểm của đường sức từ . Các đường sức từ có cắt nhau không ? Vì sao?
Bài 2: Phát biểu định luật Jun - Lenxơ. Viết hệ thức của định luật và nêu rõ ý nghĩa, đơn vị đo của từng đại lượng trong công thức.
Bài 3 : Đặt vật AB vuông góc với trục chính của một thấu kính hội tụ có tiêu cự f = 40cm. Nhìn qua thấu kính ta thấy ảnh A`B` cao gấp 2 lần AB.
Hãy cho biết ảnh A`B` là ảnh thật hay ảnh ảo? Tại sao?
Xác định vị trí của vật và của ảnh.
Cho mạch điện như hình vẽ. Trong đó UAB được giữ không đổi,
R1= 10R 2 = 15am pe kế có điện trở không đáng kể và chỉ 2,5A




Bài 4:







a, Tính hiệu điện thế hai đầu đoạn mạch AB và cường độ dòng điện qua các điện trở.
b, Thay am pe kế bằng một bóng đèn thì đèn sáng bình thường và công suất tiêu thụ điện của đoạn mạch AB là 22,5W. Tính các số chỉ ghi trên bóng đèn.
Bài làm
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