问题 问答题

(1)①如图甲所示,一导热性能良好的金属气缸静放在水平面上,活塞与气缸壁间的摩擦不计.气缸内封闭了一定质量的理想气体.现缓慢地向活塞上倒一定质量的沙土,忽略环境温度的变化,在此过程中______

A.气体的内能增大

B.气缸内分子平均动能增大

C.气缸内气体分子密度增大

D.单位时间内撞击气缸壁单位面积上的分子数增多

②下列说法中正确的是______

A.布朗运动是分子无规则运动的反映

B.气体分子间距离减小时,分子间斥力增大,引力也增大

C.导热性能各向同性的固体,一定不是单晶体

D.机械能不可能全部转化为内能

③地面上放一开口向上的气缸,用一质量为m=0.8kg的活塞封闭一定质量的气体,不计一切摩擦,外界大气压为P0=1.0×105Pa,活塞截面积为S=4cm2,重力加速度g取10m/s2,则活塞静止时,气体的压强为______Pa;若用力向下推活塞而压缩气体,对气体做功为6×105J,同时气体通过气缸向外传热4.2×105J,则气体内能变化为______J.

(2)①关于光电效应现象,下列说法中正确的是______

A.在光电效应现象中,入射光的强度越大,光电子的最大初动能越大

B.在光电效应现象中,光电子的最大初动能与照射光的频率成正比

C.对于任何一种金属都存在一个“最大波长”,入射光的波长必须小于此波长,才能产生光电效应

D.对于某种金属,只要入射光的强度足够大,就会发生光电效应

②处于激发状态的原子,在入射光的电磁场的影响下,从高能态向低能态跃迁,两个状态之间的能量差以辐射光子的形式发射出去,这种辐射叫做受激辐射.原子发生受激辐射时,发出的光子频率、发射方向等,都跟入射光子完全一样,这样使光得到加强,这就是激光产生的机理.那么,发生受激辐射时,产生激光的原子的总能量En、电势能Ep、电子动能Ek的变化情况是______

A.Ep增大、Ek减小、En减小

B.Ep减小、Ek增大、En减小

C.Ep增大、Ek增大、En增大

D.Ep减小、Ek增大、En不变

③如图乙所示,质量为m的小球B连接着轻质弹簧,静止在光滑水平面上.质量为m的小球A以某一速度向右运动,与弹簧发生碰撞,当A、B两球距离最近时弹簧的弹性势能为EP,则碰撞前A球的速度v0=______.

答案

(1)①A、金属气缸导热性能良好,由于热交换,气缸内封闭气体温度与环境温度相同,向活塞上倒一定质量的沙土时气体等温度压缩,温度不变,气体的内能不变.故A错误.

B、温度不变,则气缸内分子平均动能保持不变.故B错误.

C、气缸内封闭气体被压缩,体积减小,而质量不变,则气缸内气体分子密度增大.故C正确.

D、温度不变,气体分子的平均动能不变,平均速率不变,等温压缩时,根据玻意耳定律得知,压强增大,则单位时间内撞击气缸壁单位面积上的分子数增多.故D正确.

故选CD

②A、布朗运动是悬浮是液体中微粒做的无规则的运动,是由于液体分子撞击造成,所以朗运动是液体分子永不停息无规则运动的反映.故A正确.

B、气体分子间距离减小时,分子间同时存在的斥力和引力都增大.故B正确.

C、导热性能各向同性的固体,也有可能是单晶体.故C错误

D、机械能可能全部转化为内能.故D错误.

故选AB.

③以活塞为研究对象,根据平衡条件得

P0S+mg=PS

得到P=P0+

mg
S

代入解得P=1.2×105Pa;

由题W=6×105J,Q=-4.2×105J,则由热力学第一定律得到气体内能的变化△U=W+Q=1.8×105J,即内能增加了1.8×105J.

(2)①A、发生光电效应时,光电子的最大初动能与入射光的强度无关.故A错误.

B、根据光电效应方程EKm=hγ-W0,可知最大初动能与入射光的频率成一次函数关系,不是正比关系.故B错误.

C、入射光的频率大于极限频率时,发生光电效应,因为极限波长λ0=

c
γ0
,所以入射光的波长必须小于此波长,才能产生光电效应.故C正确.

D、光电效应与入射光的强度无关.故D错误.

故选C.

②发生受激辐射时,向外辐射光子,则原子的总能量En减小,库仑引力做正功,电势能减小.根据k

Qe
r2
=m
v2
r
,从高能态向低能态跃迁,轨道半径减小,则动能增大.故B正确,A、C、D错误.

故选B.

③当弹簧弹性势能最大时,两球的速度相同,根据动量守恒定律得:

mv0=2mv

解得:v=

v0
2

根据能量守恒定律得:

1
2
mv02=Ep+
1
2
(2m)v2

解得v0=2

Ep
m

故答案为:(1)①CD;②AB;③1.2×105Pa;内能增加了1.8×105J

(2)①C;②B;③2

Ep
m

阅读理解

British people have the worst quality of life in Europe, according to a report which highlights (强调) the long hours, bad weather, low life expectancy and high price of many goods.

In a study of ten of the largest European countries, Britain, which was considered a popular country to live in, now comes last followed by Ireland, with France and Spain topping the table.

Though British families enjoy the highest income in Europe, they still have to fight with a high cost of living, with fuel, food and alcohol all costing more than the European average.

With the high price of petrol, the UK is the second most expensive country in Europe. However, diesel (柴油) is more expensive in the UK than anywhere else in Europe.

The report by the website uSwitch analyses 10 European countries against 17 different benchmarks(基准点), from the price of gas, electricity, fuel, food and drink to the money each country spends on education, health to working conditions and the weather.

The top three countries are France, Spain and Denmark, with Sweden, Ireland and Britain coming eighth, ninth and tenth respectively.

The study comes less than a week after the United Nations moved Britain out of the top 20 list of most desirable countries to live in for the first time.

Although France and Germany were at the beginning hit hard by the global financial crisis, both have officially got out of the trouble, while Britain has yet to prove this has happened. Later this week, despite (尽管) signs of recovery in the housing market and rising sales, unemployment is still expected to have climbed to above 2.5 million for the first time since 1994.

小题1:Which country has the best quality of life in Europe according to the report?

A.Ireland.

B.France.

C.Sweden.

D.Denmark小题2:Which is TRUE according to the passage?

A.British families are suffering from the high cost of living.

B.The report comes after the website uSwitch analysed 10 Asian countries.

C.The price of petrol is higher in Britain than anywhere else in Europe.

D.The quality of British life is reported to be terrible because of the bad working conditions.小题3:The underlined word “desirable” probably means          .

A.terrible

B.attractive

C.expensive

D.different小题4: What can we infer from the last paragraph?

A.Britain is still struggling to get out of the global financial crisis.

B.Unemployment in Britain is expected to go down soon.

C.Recovery in the housing market leads to unemployment in Britain.

D.Britain has recovered from the crisis together with France and Germany.

单项选择题