Câu 25: Một máy biến áp một pha có N1= 900 vòng,N2= 90 vòng .Dây cuốn sơ cấp đấu với nguồn điện áp 110V. Xác định điện áp đầu ra của dây cuốn thứ cấp U2. Câu 26: Trong một ngày gia đình bạn Nam có sử dụng Đèn compac 25W 5 cái 5h a.Tính điện năng đèn compac tiêu thụ trong một ngày và trong 1 tháng(30 ngày) của gia đình nam, b.tính tiền điện mà bóng đèn đó sử dụng trong 1 tháng(Biết 1kWh là 1.200 đồng)

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