题目

有一种亮度可以调节的小台灯，其电路如图甲,电源电压为24Ⅴ，灯泡L的额定电压为24Ⅴ，通过灯泡L的电流跟其两端电压的关系如图乙,当灯泡正常发光时，灯丝的电阻为      Ω,调节滑动变阻器R，使灯泡的实际功率为3.6W时，灯泡两端的电压是     Ⅴ，滑动变阻器R连人电路的阻值是        Ω。 答案：60  12   40根据短文内容，判断正误，正(T)，错(F). 　Kate is a little girl. She is only five. She can't read or write. But her sister, Mary, is ten. She can read and write well. 　One day, Mary sees her little sister, Kate, in the room. She is at the desk. There is a yellow pencil in her hand. She is writing! 　　“What are you writing, Kate?” she asks. 　　“I'm writing to my friend, Jim.” Kate answers. 　　“But how can you? You can't write at all.” says Mary. 　　“Well,it doesn't matter. Jim is five. He can't read, either(也不).” (1)Kate is a little school girl. (　　) (2)Mary can read but can't write. (　　) (3)Kate is writing something with a yellow pencil. (　　) (4)Jim isn't a friend of Kate's. (　　) (5)Jim can read the letter from Kate. 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　   (　　)