问题 填空题

.一只电阻器两端的电压从2伏增加到2.8伏,通过该电阻器的电流增加了0.1安,则该电阻器的电阻值是________欧。

答案

8

电阻式导体本身的一种属性,不随电流和电压发生改变,电阻

故答案为:8

多项选择题
阅读理解

C

Stepping into a pool of water is common enough ,but who could ever imagine stopping into a pool of fish ?In February of 1974, Bill Tapp ,an Australian farmer ,saw a rain of fish that covered his farm . How surprised he must have been when he heard many fish hitting against his roof!

What caused this strange occurrence ?This is a question that had long puzzled people who study fish .The answer turned out to be a combination of wind and storm.

When it is spring in the northern part of the world ,it is fall in Australia, Throughout the autumn season ,terrible storms arise and rains flood the land .The strong winds sweep over Australia like huge vacuum(真空) cleaners, collecting seaweed ,pieces of wood , and even schools of fish .

The second thing,a dictionary will tell you the pronunciation.Most dictionaries give phonetic(语音的),or sound alphabet(音标).The phonetic alphabet shows pronunciation.The third thing,a dictionary will tell you the meaning of words.You can look up a word and find out what it means.Many words have more than one meaning,and a good dictionary will tell you au of the word's meanings.For example,in English the common word“get”has over 20 different meanings.

49.Many words have_____________ .  

A.several meanings    B.one meaning    C.few meanings  D.no meaning

50.A good dictionary will tell you____________.

A.more of word's pronunciation      B.more of the word's meanings

C.more of grammar                 D.more of the word's spelling.

51.Phonetic alphabets are used to show       .

A.handwritings   B.spelling    C.meanings  D.pronunciation

52.How many important things will most dictionaries tell you?

A.Four    B.Five    C.Three   D.Two