user-avatar
vdung298
2 năm trước
một ống dây có chiều dài l = 40cm. Gồm 4000 vòng, cho dòng điện I = 10A chạy trong ống dây a/ Tính cảm ứng từ B trong ống dây b/ Đặt đối diện với ống dây một khung dây hình vuông, có cạnh a = 5cm. Hãy tính từ thông xuyên qua khung dây.
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

15. - What’s that noise? - The children (play)_____________ tug of war. 2 A. play B. are playing C. is playing D. played 16. - What _____ you (do)_____ last weekend? A. did you do B. are you doing C. do you do D. are you do IV. What do you say in these situations? 17. Your friends are making a lot of noise. A. Please, stop making noises. B. Please, don’t stop making noises. 18. The boy is watching TV for too long. A. Go out to play with your friends. B. Don’t go out to play with your friends. 19. Some children are feeding the animals at the zoo. A. Feed the animals. B. Don’t feed the animals. 20. The teacher wants the boys to stand in line. A. Stand in line, boys! B. Don’t stand in line, boys! 21. Your mother tells you not to tease the dog. A. Tease the dog. B. Don’t tease the dog. V. Read the following passage and choose the best answer to each of the questions: REBECCA STEVENS Rebecca Stevens was the first woman to climb Mount Everest. Before she went up the highest mountain in the world, she was a journalist and lived in South London. In 1993, Rebecca left her job and her family and travelled to Asia with some other climbers. She found that life on Everest is very difficult. “You must carry everything on your back,” she explained, “so you can only things that you will need. You can’t wash on the mountain, and in the end I didn’t even take a toothbrush. I am usually a clean person but there is no water, only snow. Water is very heavy so you only take enough to drink!” Rebecca became famous when she reached the top of Mount Everest on May 17, 1993. After that, she wrote a book about the trip and people often asked her to talk about it. She got a new job too, on a science programme on television. 22. Where was Rebecca Stevens from? A. England B. Asia C. Everest D. The South 23. Before she climbed Everest, Rebecca Stevens was a __________. A. climber B. journalist C. traveller D. scientist 24. Why did Rebecca Stevens become famous? A. She left her job and her family and travelled to Asia. B. She found that life on Everest is very difficult. C. She reached the top of Mount Everest in 1993. D. She was the first woman to climb Mount Everest. 25. Life on Everest is very difficult because __________. A. it is very high C. there is no water there B. you can’t take things with you D. there are no toothbrushes

Exercise 1: 1- Mary (be) worried if you don’t come to the station. 2- I (ask) Tom if I (see) him tomorrow. 3- If he (get up) earlier, he’d get to work on time. 4- If it (rain) this weekend, we (not be able) to play tennis. 5- If he had a car, he (take) you to HCM city. Exercise 2: Put the verbs into the correct form: 1- They (help) you if they have time. 2- If the bus (not come), we’ll go by bikes. 3- If you (drive) more carefully, you (not have) so many accidents as last year 4- If he (not be) sick, he (go) to school yesterday. 5- I could help you if you (trust) me more. 6- If he (sell) more product, he’d earn more. 7- If I (be) you yesterday, I (lend) her my car. 8- There (be) trouble if they try to stop him leaving. 9- I’ll do it if he (ask) me. 10- If you (look after) the car, it couldn’t go away. Exercise 3 : Put the verb in brackets into the correct tenses. 1. If I had known that you were in hospital I (visit) you. 2. The ground was very soft. But for that, my horse (win). 3. If you (arrive) ten minutes earlier you would have got a seat. 4. You would have seen my garden at its best if you (be) here last week. 5. But for his quickness I (be) killed.

2018 © Loga - Không Ngừng Sáng Tạo - Bùng Cháy Đam Mê
Loga Team