[物理]97期末不專業簡答題

看板NTUBIME102HW作者sophiamag19 (秋人)時間15年前 (2010/06/23 18:31)推噓23(25推 2噓 7→)

留言34則, 18人參與討論串1/1

一、簡答題(9x5=45%) 1. What is meant by "Tranverse Doppler Effect" Ans:橫向都卜勒效應:一般討論都卜勒效應,都是針對光源(S)與偵測器(D)在一直線上彼此接近或遠離的情況,然而當S移動的路線不會經過D,當S的速度V垂直於S與D的連線時,也就是S與D距離最短時,此瞬間S既不是接近亦不是遠離D,此時的都卜勒效應稱為橫向都卜勒效應(若S發射的是聲波則沒有都卜勒效應) 2. Explain that how optical fiber transmit signal Ans:光在optical fiber(光纖)內壁進行多次全反射 3. Light travels in vaccum with wavelenth λ and velocity c. What are the corresponding wavelength and velocity of the light when it is traveling in a medium with refractive index n? Ans:λ'=λ/n , v=c/n 4.The important four electromagnetic laws are gererally known as the Maxwell equations. Yet, curiously enough, Maxwell completely did not have a hand in three of the four equations, with exceptions called the Ampere-Maxwell law. Explain why shoulld these equations called the "Maxwell equations"? Ans:因為馬克斯威爾最早提出這些公式的原形 (onepiece584更正:Maxwell提出重要的一條，讓電學和磁學建立關係，四條式子並非全Maxwell提出) 5.Why an incident light changes its phase by π when it is reflected from an interface with higher refraction index? 不會=ˇ= 6.Give a sample explanation of what is meant by Scanning Tunneling Microscope or simply STM? Ans:是一種利用量子理論中的隧道效應探測物質表面結構的儀器。它主要是利用一根非常細的金屬探針，針尖的電子會跳到待測物體表面上形成穿隧電流，同時，物體表面的高低會影響穿隧電流的大小，針尖隨著物體表面的高低上下移動以維持穩定的電流，依此來觀測物體表面的形貌。 7.Why Einstein;s theory of "photoelectric effect" is so important? Ans:說明了光有粒子性,使光量子理論被接受 8.In 1923, Authur Compton successfully demonstrated his well known "Compton scattering" experiment. What has he proved? What is the Compton wavelength. Ans:證明光不僅僅具有波動性，光在某種情況下也能表現出粒子性。當X射線或伽瑪射線的光子跟物質交互作用時，會失去能量而導致波長變長。 △λ=h/mc(1-cosφ) 9.An electron is trapped in an 1-dimemsional infinite potential well of width b.WRITE down the normalized wave function and the quantized energy levels En Ans: +∞ ∫-∞ ψn^2 (x)dx=1 , ψn^2 (x) =A^2(sin(nπx/b)^2 , A =(2/b)^(1/2) En=(nh)^2/(8m(b^2)),n=1,2,3… (這題不是很確定,麻煩認真的小孩檢查一下囉!多謝!) 我不會第五題,然後簡答有可能有錯=口=,如果有看到麻煩說一聲阿!! 95下期末的第三題 3. Explain the followings. (a) What is the photoelectric effect? Give a least one example of application by this effect. ANS: (a) 如果一束光的波長夠短,將它照在一個乾淨的金屬表面上,則光可將電子擊出金屬表面 /數位相機、數位攝影機 (b) What is Lorentz transformation?(勞倫茲轉換) ANS: 是觀測者在不同慣性座標之間對物理量進行測量時所進行的轉換關係 (c) What is time dilation? ANS: 當兩事件在慣性座標的相同位置發生,則在此座標所測的時間間隔稱為原時距,從任何其他慣性座標所測得的時間間隔必大於原時距,此時距相對於原時距,增加的部分稱為 time dilation(時間膨脹) 5. Write down the Maxwell equations and explain the meaning of each equation in detail. (12%) 詳見課本內容 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.112.7.59

推

onepiece584

06/23 18:42, , 1^F

06/23 18:42, 1^F

→

onepiece584

06/23 18:42, , 2^F

06/23 18:42, 2^F

推

erickiller10

06/23 18:58, , 3^F

06/23 18:58, 3^F