问题 填空题

如图,电源电压保持不变,当开关S由断开到闭合时,电流表的示数将______,电压表与电流表示数的比值将______(填“变大”“变小”或“不变”).

答案

(1)当开关断开时,灯泡L与电阻R串联,电压表测量电阻R两端的电压,电流表测量电路中的电流;当开关S闭合时,灯泡L被短路,只有R工作,电压表测量电阻两端的电压,电流表测量电路中的电流,此时电路中的总电阻变小,根据I=

U
R
可知电路电流变小,即电流表的示数变大;

(2)∵

U
I
=R,且电阻R的阻值不变,

∴电压表与电流表示数的比值不变.

故答案为:变大;不变.

阅读理解

Lost Cat Returned To Owner 12 Years Later

April 3, 2014 – Linda Edwards of Las Vegas, Nevada is full of happiness because her long lost cat Spaz has been returned to her – 12 years after he first went missing!

Spaz first went missing in 2002 and Edwards looked for him every day for three months. She searched all around her town and even wrote letters to some newspapers for help and was never able to find him. At the end of the three months, on New Year’s Eve of 2002 her searching stopped.

But someone recently discovered a dirty, thin stray cat (流浪猫) and took him into a West Flamingo Animal Hospital. The people working in the hospital checked the cat and were sure enough that his name was Spaz and he belonged to Edwards!

“An old lady found a kitty on Sunday and brought him here. We scanned (扫描) him for a microchip (微芯片) and we were able to find out his owner. The kitty, whose name is Spaz, has been missing for 12 years!” the animal hospital wrote on their Facebook page early last week.

Microchipping pets is a way to recognize if a stray animal belongs to anyone who could be missing them. Microchipping pets allows animal services to learn if they have a family waiting for them. Microchips are only about the size of a grain of rice and can only be removed by operation.

Edwards is very thankful she had Spaz microchipped and was so excited to get him back!

“I feel like I have a second chance,” she said. “This would have never happened if it weren’t for microchips.”

小题1:The cat got lost ______.

A.three months ago

B.12 years ago

C.on April 3, 2014

D.on New Year’s Eve, 2002小题2:After the hospital checked the cat, they knew ______.

A.its feeling

B.its hobby

C.its stray life

D.its owner’s name小题3:______ make(s) it possible for owners to find their lost pets.

A.The microchip

B.Animal hospitals

C.The newspaper

D.Family members

选择题