题干

下列说法中正确的是(  )

A:家中同时使用的用电器越多,家庭电路中总电流就越大

B:电流通过用电器所做的电功越多,这个用电器的电功率就越大

C:在相同时间内,额定功率越大的用电器,工作时消耗的电能就越多

D:电炉子工作时,电炉丝热得发红,而连接电炉子的导线并不太热,是因为电炉丝中电流比导线中电流大得多

上一题 下一题 0.0难度 选择题 更新时间:2019-09-12 04:47:47

答案(点此获取答案解析)

A

同类题3

    Where in the world can you take an hour’s train ride, and pass a forest, a London street, a scene from the Wild West, and a burning building that never burns down? There’s only one place, and that’s Hollywood, in California. The scenes you see from the tourist train are film sets(布景) in the Universal Studios, one of the oldest and largest movie companies(公司) in the USA.
    A visit to Universal Studios brings back memories of great days of Hollywood, the films and the stars. But they are only memories. Hollywood isn't quite the same as it used to be. Costs have gone up and confidence has gone down. Movie-makers are afraid to spend their money on expensive new ideas. Instead, they repeat old ones.
    The film industry is changing fast. Teenagers still go out to the movies. The theatre is a good place to meet friends away from home. But older people mostly stay home to watch series, like Dynasty have become as important to Hollywood as expensive movies. These “soap opera”, as they are called, show rich, powerful families living in beautiful homes and wearing beautiful clothes. But the actors and actresses are nearly all middle-aged, like many of the people who watch them.
    Though it is soap operas that are keeping the film-makers of Hollywood in Business, big films are still being made in America. But more and more of them are made outside Hollywood. New York is the most important new center, but there are many others as well. Movie-makers have realized that they don't need Hollywood any more. Modern cameras and real houses instead of expensively made copies in a studio. Other states, especially Florida and Texas, are working hard to take the film business away from California. They are offering better working conditions and lower cost.
    But Hollywood is fighting back. The state of California is trying hard to keep its best-known industry.