问题
问答题
下列各种电器中，利用电流热效应工作的是（ ）
A．电动机
B．电冰箱
C．电饭锅
D．电风扇
答案
电动机、电冰箱、电风扇机工作时，电能主要转化为机械能．不符合题意．
电饭锅工作时，电能转化为内能．符合题意．
故选C．
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下列各种电器中，利用电流热效应工作的是（ ）
A．电动机
B．电冰箱
C．电饭锅
D．电风扇
电动机、电冰箱、电风扇机工作时，电能主要转化为机械能．不符合题意．
电饭锅工作时，电能转化为内能．符合题意．
故选C．
Billy is fourteen years old and in the ninth grade. He has a 36 job which gets him 37 at five o'clock every morning. He is a 38 . Each morning, Billy leaves the house at 5: l5 to go to the corner 39 the newspapers are. The newspapers are delivered （递）to the 40 by truck at midnight. He always takes a wagon (手推车) to carry them. In 41 , it is still dark and cold when he gets up, but during the rest of the year it is bright and warm. Billy must deliver the newspapers to the houses of people on his route (线路) in all kinds of weather. He tries to put each 42 on the porch (门廊) where it will be protected from 43 , rain or snow. His 44 think he does a good job. Sometimes they give him 45 . Billy 46 about $70 per month, and he is saving some of the money to go to college. He spends the rest 47 records and clothes. Once a month, he has to 48 money from his customers. Since many of them 49 during the day, Billy has to collect the money 50 . Sometimes, when Billy is 51 , his older brother has to 52 the newspapers. Once Billy's father had to help as well. Billy has seventy customers now, 53 he hopes to get more soon. Some day, if he gets many more customers, Billy might win a prize for being an outstanding(杰出的) newspaper boy. He wants to win a 54 to Europe, but he will also be happy 55 he wins a new bicycle.
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