问题 问答题

按要求作图:

(1)如图1所示,某光线经凸透镜折射后经过焦点F,请画出该入射光线.

(2)小明在探究“影响电磁铁磁性强弱的因素”的实验中,通电螺线管的磁感线如图所示,请在图2中标出电源的正负极.

答案

(1)平行于主光轴的光线经凸透镜折射后将过焦点,如图所示;

(2)磁感线总是从磁体的N极出发、回到S极,所以螺线管的左端为S极、右端为N极;右手握住螺线管,大拇指指向螺线管的右端(N极),根据四指的弯向可以标出螺线管的电流方向,如下图所示:

阅读理解
Astronauts’ meals have come a long way from the free-dried powders and semi—liquid pastes of decades ago,now US scientists want to grow vegetables in mini—greenhouses on the moon.
Scientists say they are looking forward to a time when residents of future lunar or even Martian outsteps will be able to dine on fresh vegetables.Paragon Space Development Corporation has unveiled what it called the first step toward growing flowers——and eventually food on the moon.
This is a sealed greenhouse that looks like a bell jar encased in a 46-cm triangular aluminiumframe.It is designed to safely land a laboratory plant on the lunar surface,and protect it while it grows.
The miniature greenhouse is to be launched into space by Odyssey Moon Ltd, a participant in the Google Lunar X Prize. This competition offers $21 million to any entrant who can launch, land and operate a rover on the lunar surface.
Paragon officials say future testing of the “Lunar Oasis” will be driven by Odyssey’s flight Schedule, which will not happen until 2012 at the earliest.
When it does lift off the greenhouse will contain the seeds of Brassica, a hardy plant related to Brussels sprouts and cabbage. Because Brassica goes from seed to flower in just 14 days, it can complete its life cycle in a single lunar night.
“Colonizing the Moon or Mars seems so far away,but it is important that we do this research now. ”Paragon president Jane Poynter said.
“It takes a long time to get a lot of research, and to get integrated, reliable efficient systems before colonists move in. ”she said.
小题1:The article is written mainly to__________.
A.predict the astronauts’ meals in the future
B.introduce an experiment “Lunar Oasis’’
C.tell us the future development of astronomy
D.focus on the human’s great progress
小题2:The article implies that__________.
A.astronauts can grow flowers in space at present
B.Paragon and NASA will carry out the test separately
C.Lunar Oasis is a series of experiments carried out in space
D.the earliest testing of the Lunar Oasis may be in 2012
小题3:The underlined word “colonists” in the last paragraph probably has the meaning of______.
A.plantsB.wild beastsC.human beingsD.scientists
小题4:The seeds of Brassica will be contained in the greenhouse mainly because _________.
A.their life cycle is much shorter
B.they are more nutritious than other food
C.they are related to Brussels sprouts and cabbage
D.they are very delicious
单项选择题