Chọn đáp án A

+ Công thức máy biến áp: U 1 U 2 = N 1 N 2

Chào em ! Em có thể tham khảo bài này nhé :

Learning a new language is always a challenge for anyone, but learning English can become a harmonious combination of researching and entertainment if we are flexible. Besides stressful studying hours, we can still learn English even when we are entertaining. Learners can turn their hobbies such as reading, watching movies or listening to music into a powerful assistant in learning this language. While watching English movies, we can also listen to what the actors and actresses say in order to get familiar with the Western accent also as the way they use the sentence structure in a parular context. Next, we can learn more vocabulary and have a thorough understanding of grammar by reading English lyrics and books. On weekends, instead of playing games or hanging out with friends, we can spend some of our spare time to join the English clubs. These clubs provide an open English-communicating environment, enabling us to communicate confidently and recognize our mistakes. This can help us to be more interested in learning English, and talking to native speakers can encourage us to learn more about this language. In general, English is not too difficult for us to learn; however, we should know how to learn it properly in order to make the best use of it.

Chúc em học tốt !!! Study hard :)

Biểu diễn vecto các điện áp.

Hiệu suất của động cơ H=A/P

→ P = A H = 8 , 5 0 , 85 = 10 kW.

→ Điện trở trong của động cơ R d c = P I 2 = 10000 50 2 = 4 Ω  

→ Z d c = R cos 30 0 = 8 3 Ω.

→ U d c = I Z d c = 50 8 3 = 400 3 V.

Từ giản đồ vecto, ta thấy rằng góc hợp với U d c → và U d → là 150 độ .

→ U = 125 2 + 400 3 2 − 2.125. 400 3 cos 150 0 = 345   V  

Đáp án B

một số bệnh: rối loạn tiêu hóa, khó tiêu, trào ngược dạ dày thực quản, đau bụng, tiêu chảy, ợ chua