题目

在皮带的带动下，固定在发动机轴上的正方形线圈以角速度50 rad/s匀速转动，线圈边长为20 cm，匝数为10匝，线圈总电阻为1 Ω，转动轴OO′穿过线圈对边的中点，整个装置处在磁感应强度为1 T的匀强磁场中.线圈中产生的交变电流经滑环电刷向qΩ的电阻供电，求： 图3-2-9(1)交流安培表和伏特表的示数;(2)电源内阻的发热功率和电源的输出功率.At Beijing’s Beihai Park, there is a good place for visitors. Right now, there’s a lotus(莲花) scene on the park’s lake. ★Enjoying the lotus by boat is a great thing that tourists in Beijing don’t want to miss.　　Beihai Park’s lotus festival is in its 13th year. The festival came to a stop in 1998 because of a conflict(冲突) between the flower and the fish. It started again in 2006. The park was once a place where the royals(王室) came to enjoy the lotus.　　The Beihai Park lotus festival runs until August the 10th. A lotus festival is also featured at the Lian Hua Chi, or the Lotus Pond Park in the west of Beijing.　　Telephone: 86010-64033225　　Address: No.1, Wenjin Street, Beijing, China　　Bus: 5, 101, 103, 107, 109, 111, 701, 814, 823, 846　　Opening Hours: 6:00 am to 10:00 pm51. When can we come to Beihai Park to see the lotus festival? ____.　A. In August　　 B. In September　 C. In October　 D. In November 52. From which year did the festival stop for some time? ____.　A. 2008　　　　 B. 2006　　　　　 C. 2003　　　 D. 199853. How many buses can take us to Beihai Park? ____.　A. Eight　　　 B. Nine　　 　　　C. Ten　　　　 D. Eleven54. Where can we see lotus in Beijing? ____.　A. In Beihai Park　 B. In Lian Hua Chi　　 C. In Lotus Pond Park　 D. All the above55. According to the passage, we can know that ____.　 A. the tourists don’t like the lotus at all 　　 B. Beihai Park’s lotus festival has a 13-year history　 C. the Lotus Pond Park is in the east of Beijing　 D. the lotus festival lasts until August 12th