题目

有一种电加热恒温箱，工作原理如图所示。控制电路由电压为U1=9V的电源、开关、电磁继电器（线圈电阻不计）、电阻箱R0和热敏电阻R1组成；工作电路由电压为U2=220V的电源和电阻为R2=44Ω的电热丝组成。其中，电磁继电器只有当线圈中电流达到60mA时，衔铁才吸合，切断工作电路；热敏电阻R1的阻值随温度变化关系如图所示。（1）求电热丝工作时的功率和在10min内产生的热量。（2）如果恒温箱的温度设定为50℃，求电阻箱R0应接入电路的阻值。（3）若要 阅读理解 　　There were smiling children all the way．Clearly they knew at what time the train passed their homes and they made it their business to stand along the railway, were to complete strangers and cheer them up as they rushed towards Penage．Often whole families stood outside their homes and waved and smiled as if those on the trains were their favorite relatives．This is the simple village people of Malaysia．I was moved． 　　I had always traveled to Malaysia by plane or car, so this was the first time I was on a train．I did not particularlf relish the long train joumey and had brought along a dozen magazines to read and reread．I looked about the train．There was not one familiar I sighed and sat down to read my Economics 　　It was not long before the train was across the Causeway and in Malaysia．Johore Baru was just another city like Singapore, so I was tired of looking at the crowds of people as they hurried past．As we went beyond the city, I watched the straight rows of rubber trees and miles and miles of green．Then the first village came into sight．Immediately I came alive, I decided to wave back． 　　From then on my joumey became imeresting．I threw my magazine into the waste basket and decided to join in Malaysian life．Then everything came alive．The mountains seemed to speak to me．Even the trees were smiling．I stared t everything as if I was looking at it for the first time． 　　The day passed fast and I even forgot to have my lunch until I felt hungry．I looked at my wat ch and was surprised that it was 3∶00 p. m．Soon the train pulled up at Butterworth I looked at the people all around me．They all looked beautiful．When my uncle arrive with, I threw my around him to give him a warm hug．I had never done this before．He seemed surprised and then his weather-beaten face warmed up with a huge smile．We walked arm in arm to his car． 　　I looked forward to the return journey． (1) The author expected the train trip to be ________． [　　] A． adventurous B． pleasnt C． exciting D． dull (2) What did the author remember most fondly of her train trip? [　　] A． The friendly country people． B． The mountains along the way． C． The crowds of people in the streets． D． The simple lunch served on the train． (3) Which of the following words can best take the place of the word“relish”in the second paragraph? [　　] A． choose B． enjoy C． prepare for D． carry on (4) Where was the writer going? [　　] A． Johore Baru． B． The Causeway． C． Bunerworth． D． Singapore． (5) What can we learn from the story? [　　] A． Comfort in traveling by train． B． Pleasure of living in the country． C． Reading gives people delight． D． Smiles brighten people up．