题干

一个γ光子的能量为E,动量为P,射到一个静止的电子上,被电子反射回来,其动量大小变为P1,能量变为E1,电子获得的动量为P2,动能为E2则有

A:E1═E P1═P

B:E1 < E P1 < P

C:E2 < E P2 < P

D:E2 <E P2>P

上一题 下一题 0.0难度 选择题 更新时间:2015-07-10 11:52:12

答案(点此获取答案解析)

D

同类题1

阅读理解

    The Five Best Countries TO Move To For Retirement

    Retiring in a different country is gaming popularity. Below are five of the best countries to seek retirement

    Costa Rica

    Mild climate, breathtaking landscapes and beaches draw retirees(退休人员)to Costa Rica. The country readily welcomes immigrants and offers a simple residency process. With a monthly income of at least $ 1,000 per month from Social Security or a similar source, people enjoy a high standard of living at a much lower cost than the U. S.

Malaysia

    Retirees who choose to make Malaysia home will appreciate its rich culture and attractive scenery. Moreover, the country offers modern facilities at modest prices. Immigrants enjoy convenience and comfort in their daily life. You will find low-cost rental units, delicious street food, and various shopping malls.

Mexico

    Because it's close to the U.S., Mexico draws more than a million American retirees to its borders. Increasing immigrant communities enjoy seaside living and conversations with friendly. English speaking locals. Plus, legal residents over the age of 60 receive airline, grocery, and restaurant discounts.

Panama

    Gentle ocean wind takes the heat out of hot year-round temperatures, which has been the chief attraction to foreign retirees. Beautiful beaches and a booming economy also attract retirees to Panama. An income of $2,000 per month covers modest living costs. Furthermore, the country offers discounts to retirees with a special visa.

Ecuador

    Lazy coastal towns, sun-shining hot spots, and nature-filled views wait for immigrants seeking a carefree lifestyle. Public transportation costs in Ecuador make owning a vehicle unnecessary. A bus ride only costs 25 cents and taxi rides will run about $3.

同类题2

阅读理解

    When Warren Buffett was asked about the secret to his wealth and success, he said that he read every day—500 pages. Unfortunately, if you're already working 9-5, you might not have the time to read at all, let alone an entire book a day. But what if you could get the benefits of reading without sacrificing all of your free time? You can! With the Blinkist app, you get the key learning from the best notification books in minutes, not hours or days. Our experts transform these books into quick, memorable, easy-to-understand insights. Start with the 3 most-read titles on self-improvement and see if you don't feel a little more satisfied already.

    ⒈Thirteen Things Mentally Strong People Don't Do by Amy Morin

    12min

    Read it on Blinklst

    You can't escape misfortune in life. But you can change how you respond it. Do you struggle to get over your failures? Or talk a lot about things out of your control? Getting over these obstacles can have a very great influence on your everyday life. Morin shares how her most successful therapy patients overcame these difficulties.

    ⒉How to Stop Worrying and Start Living by Dale Carnegie

    19min

    Read it on Blinklst

    How would you feel it someone told you on Sunday evening that, come Monday morning, you would be thrown into a torture chamber(刑讯室)? Would you worry? Probably. But there would be a way to deal with those worries. Ever wondered why you can't stop worrying about something? No matter how hard you try, are you always thinking and talking on the same issue? By defining the source of your stress, you can get over it once and for all. Carnegie came up with a timeless formula that helps you handle any overthinking situation.

    ⒊How Will You Measure Your Life? by Clayton M. Christensen, James Allworth and Karen Dillon

    13min

    Read it on Blinklst

    What do you think would make you happier at work? Perhaps a little more pay might be nice, or maybe some more admiration from fellow colleagues. Are you making the right trade-offs in life? While career achievements can be satisfying, neglecting your family and friends can be harmful in the long-run – in ways you can't even imagine.