发电机输出功率为100kW，输出电压是250V，用户需要的电压是220V，发电机到用户输电线电阻为10Ω，要求输电线中因发热而损失的功率为输送功率的4％.
(1)画出此输电线路的示意图；
(2)求输电线路中升压变压器和降压变压器原副线圈的匝数比；
(3)用户得到的电功率是多少。
(1) )略(2)1:20；240:11 (3 
作图。（2分）
（2分）
（2分）
（2分）
本题考查电能的输送以及理想变压器规律，根据公式
和
解题，
| 在B栏中找出A栏的正确答语。 | |
| A ( )1. What's that? ( )2. Who's that woman? ( )3. How are you? ( )4. How old are you? ( )5. Where are you from? ( )6. How many monkeys can you see? ( )7. Can I have some ice-cream? ( )8. How many pencils do you have? ( )9. What's your mother? ( )10. How do you do? ( )11. Can I use your pen? ( )12. Do you like bananas? ( )13. Who's that woman? ( )14. How many cats can you see? ( )15. Where is the ball? | B a. I have thirteen pencils. b. That's a pen. c. I'm from China. d. How do you do ? e. She is a teacher. f. I'm fine. g. She is my mother. h. I'm eleven. i. I can see twenty-two monkeys. J. Sure. k. Yes, I do. l. She's my mother. m. I can see 11. n. It's under the chair. o. Sure. |