Does Huygens’ princirfw e 3uas*0eynh: 0,pple apply to sound waves? To water waves? Explain.

What is the evidencee)r/x 6. nvx)b( d pcen5/fiok that light is energy?

Why is light sometimes described as rays andtw g8d*yx;po 6 sometimes as waves?

We can hear sounds around cooko;k :v*axe+ mvbv4 z. sf)w7pvib-;rners, but we cannot see around corners; yet both sound and light are waves. a:bboxv;ke vok; s)+*4z.mfwv -7 vipExplain the difference.

If Young’s double-slit experiment were submerged in water, h.9o7 8 m+lk :zy*gkqt moe9xynow would the fringe pattern be changlzto:mn*yg k+ye .ko7m98 qx9 ed?

Monochromatic red light is incident on a double slit, and the interference p mwun .z*okdff6d3h11 6*+ycm*ez pok attern is viewed on a screen some distance away. Explain how the fringe pattern would change if the red light source is replacedd*+ uwzh6ok.oe c1 n16md kp yf*z3*mf by a blue light source.

Two rays of light from the sam*l,oc2(rsn2nj(zijm ,p ( pjue source destructively interfere if their path lengthl2psz(n ur,( ,n c*(pj jmio2js differ by how much?

Why was the observation of the double-slit interference pattern more convinci)eh8 n u-p essc,7e9*zetud.cng evidence for tp7tss u-e.n8e,e* eh9 cc)ud zhe wave theory of light than the observation of diffraction?

Compare a double-slit experiment for sound waves to that for light wavewxrd* xs*4lrys73 om0 s. Discuss the similarities ax7l04myrosw* 3xrsd * nd differences.

Why doesn’t the light from the two headlights of18voyxf 3k**m ric i8k a distant car produce an interference pat8r i1*c*xyik8o v kfm3tern?

Suppose white light falls oprom (vj3j8lzn m 5*0gn the two slits of Fig. 24–7, but one slit is covered by apzno mrlj* 8j5(g0m3v red filter (700 nm) and the other by a blue filter (450 nm). Describe the pattern on the screen.

When white light passes through a flat piece of windowb)wi3x+: (bfg eg xl.yo qp2)d glass, it is not broken down int .(d) :wx3beqg2)b+gipfy xo lo colors as it is by a prism. Explain.

For both converging and divergiceel lxci66y gi38 49kh,u -pgng lenses, discuss how the focal length for red light differs from that f8 y9pglgx keicc6ei6 h,u34l-or violet light.

A ray of light is refracted8nd6)* c ak 6az)xthafczsyik(c ,6(w through three different materials (Fig. 24–55). Rank the materials according to their index of refraction, least to 6awzxck nhf(s8kc)c 6* dy ia(za6t,)greatest.

Hold one hand close to your eye and focus on a tko6x zt),nr:dg hhj)4-8rq g distant light source through a narrow slit between two fingers. (Adjust your fingers to obtain the best pattern.) Describer8,d4t h gg-) oz jrx)n:6ktqh the pattern that you see.

What happens to the diffraction pattern of a single slitt3qcnu sh 7 ibk+5kh2. if the whole apparatus is immersed in (a) water, (b) a vask+bu3hkq5nthi c 2. 7cuum, instead of in air.

For diffraction by a single slit, what is the effect of increasing (asc:ku7.kzj ( t) the slit width, and (b) the wavelengtk.u zjc:t s7(kh?

What is the difference in the interference patterns formjvvqh .z+c31-inaiq(8oxpf si2wx/1 ed (a) by two slits $^{-4}\;cm^2$ apart, (b) by a diffraction grating containing $10^4lines/cm$?

For a diffraction grating, what is jlwzzr- 1n(p2 the advantage of (a) many slits, (b) closely spaced slits?j(lw1rnp z-2z

White light strikes (a) a diffraction grating, and (b) a prism. A raib;-obi4 sd cg8nbow appears on a wall just below the direction of the horizontal incident beam in each case. What is t- d8bb;o 4gscihe color of the top of the rainbow in each case? Explain.

For light consisting of wavelengths between 400 nm and 700 nm, incident normal rc0h:6.vhlnemg : 8xar5v dr2ly on a diffraction grating, for what orders (i: rde r5rgv h.hc0nla8:x2 6mvf any) would there be overlap in the observed spectrum? Does your answer depend on the slit spacing?

Why are interference fringes notice.nyjz6zvp9 sx /wr2d2 able only for a thin film like a soap bubble andj/s9d. 2zpn2vx6 rywz not for a thick piece of glass, say?

When a compact disk (CD) is held atozc+,ba 8 ssbd8rw*ud j c;n,bo .3x9d an angle in white light, the reflected light is a full spectrum (Fig. 24–56). Explain.a*bcd,o zdoj3bds ;r,xwn98 +8.ucs b What would you expect to see if monochromatic light was used?

Why are Newton’s rings (Fig. dpy b2 (sc()vd3 zut*7f0nvia24–31) closer together farther from the center?

Some coated lenses appear greenish yellow when seen by reflected light. What wa(*60iz2y7nvee yelz y5nx 7uvvelengths do you suppose the coating is designed to tryei2l6vyn7xvzuye5 7e(n0z *ansmit completely?

A drop of oil on a pond appears bright at its edges, where its thicknessyzbgvox;3o7 qb03*jx is much less than the wavelengths of visible light. What can you say abo j;7xvx33qobz 0 b*gyout the index of refraction of the oil?

What does polarization tell us ab s. 0qvekack-z,vm4,vout the nature of light?

Explain the advantage of polabn7-ma0*on9zf - qmg urized sunglasses over normal tinted sunglasses.

How can you tell if a pair of sunglasseh6zpl8q1 awje96ru tvb l2(-p/dt8va s is polarizing or not?

Two polarized sheets r;;b mkz3eglacgnn : 5i ;u/vaph9-4x lotated at an angle of 90$^{\circ}\,$ with respect to each other will not let any light through. Three polarized sheets, each rotated at an angle of 45$^{\circ}\,$ with respect to each other, will let some light through. What will happen to unpolarized light if you align four polarized sheets, each rotated at an angle of 30$^{\circ}\,$ with respect to the one in front of it?

What would be the colfy(94 oyic efc/8h0 xbor of the sky if the Earth had no atmosphere?

If the Earth’s atmosphere were 50 times dens;sw( wkcj*( got r;x5ner than it is, would sunlight still be white, or cx;w*k(rwgn; (ts oj5would it be some other color?

  Monochromatic light falling on two slits 0.016 mm ap9;sl p weg1-xrart produces the fifth-order fringe at 91 wpxl-er g;san 8.8$^{\circ}\,$ angle. What is the wavelength of the light used?    $ \times10^{-7 }\;m$

  The third-order fringe of 610 nm light is observed at an ang8 ydtf50 .mhnmle of 18$^{\circ}\,$ when the light falls on two narrow slits. How far apart are the slits?    $\mu m$

  Monochromatic light falls on two very narrow slits 0.048 gy 44 owj47x d7 .wnry/0xomy y35sygwmm apart. Successive fringes on a screen 5.00 m d/wyxoy ogn xr.w740jy 57gys4 34mywaway are 6.5 cm apart near the center of the pattern. Determine the wavelength and frequency of the light.
$\lambda\;=\;$    $m$
$f$ =    Hz

  A parallel beam of light from a1h::j)ver 9 pvamk( sp He-Ne laser, with a wavelength 656 nm, falls on two very narrow slits 0.060 )e(jha9 k rm1pv::ps vmm apart. How far apart are the fringes in the center of the pattern on a screen 3.6 m away?    cm

  Light of wavelength 60 1 czogifmaq4pv9t 6md,+ n3c80 nm falls on two slits and produces an interference pattern in which the fourth-order fringe is 38 mm from ti mp nzg mt1fd63cv o4,+0qc9ahe central fringe on a screen 2.0 m away. What is the separation of the two slits?    mm

  If 720-nm and 660-nm light passes through tw0jis( ojwfe dat4 qsg(rt;6) 5o slits 0.58 mm apart, how far apart are the second-order 6 ojw;t 0sra(s(g)etfjqd45ifringes for these two wavelengths on a screen 1.0 m away?    mm

  In a double-slit experiment, it is f( gj6i7hz6 tmzound that blue light of wavelength 460 nm gives a second-order maximum at a certain locationz(zh t6mgj6i7 on the screen. What wavelength of visible light would have a minimum at the same location?    nm

Water waves having parallel crests 2.5 cm apart pass through two openings 5.0 u,y km8p ,6,sz9xx ep1qr- qrrcm apart in a board. At a point 2.0 m beyond the board, at what angle relative to the “straight-through” direction would there b p 1r-emr,6,qzxr8x,ukps yq9 e little or no wave action?

Suppose a thin piece of glass is placed in front of the lower slit in Fd/r8rtg.yq6ld ajnp6e 7 t)p 5ig. 24–7 so tha)rr6yl/n d5tt 7qa 6je.gp8dpt the two waves enter the slits 180$^{\circ}\,$ out of phase (Fig. 24–57). Describe in detail the interference pattern on the screen.
24-7
24-57

  In a double-slit experiment, t sx, zjc q/-iw16tu:1fnod4gahe third-order maximum for light of wavelength 500 nm is located 12 mm from th a1txog4 qsw,if-d6n1:zu j /ce central bright spot on a screen 1.6 m from the slits. Light of wavelength 650 nm is then projected through the same slits. How far from the central bright spot will the second-order maximum of this light be located?    mm

  Two narrow slits separated by 0b:-eyf ; tbccbr:7st1.0 mm are illuminated by 544 nm light. Find the distance betsbber; tc:bf:yc7 0- tween adjacent bright fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 nm in air p.:brxi,m9rc.x nv.f falls on two slits $6.00 \times10^{-2 }\;mm$ apart. The slits are immersed in water, as is a viewing screen 40.0 cm away. How far apart are the fringes on the screen?    mm

  A very thin sheet of plastic (n=1.60) covers one slit ofgu;pml5 5k nm7 a double-slit apparatus illuminated by 640-nm light. The center point on tm 7l5 5mgkn;puhe screen, instead of being a maximum, is dark. What is the (minimum) thickness of the plastic?    nm

  By what percent, approximately, does the speed of red light (700 nm) exceed1 13jdi qyv*mr that of violet light (400 nm) in silicate flint glass? (S1m3i 1d*yqj vree Fig. 24–14.)    %

  A light beam strikes a piece of glass at a 60.02z vz g hi.)ooz.wzt+t,w5oa4 0$^{\circ}\,$ incident angle. The beam contains two wavelengths, 450.0 nm and 700.0 nm, for which the index of refraction of the glass is 1.4820 and 1.4742, respectively. What is the angle between the two refracted beams?    $^{\circ}\,$

  A parallel beam of light containinyj mkf rom:**1g two wavelengths, $\lambda_1\;=\;450\;nm$ and $\lambda_2\;=\;650\;nm$, enters the silicate flint glass of an equilateral prism as shown in Fig. 24–58. At what angle does each beam leave the prism (give angle with normal to the face)?
$\theta_{d1}$    $^{\circ}\,$ from the normal
$\theta_{d2}$    $^{\circ}\,$ from the normal

  If 580-nm light falls on a slit 0.0j55u + tr+0 7tfervza(r n0mfc440 mm wide, what is the full angular width of the central diffracti0e0(+am5fun7jrzt 5crrt +f von peak?    $^{\circ}\,$

  Monochromatic light falls on a slit9hwp:.ef 0ws o that is $ 2.60\times10^{ -3}\;mm$ wide. If the angle between the first dark fringes on either side of the central maximum is 35.0$^{\circ}\,$ (dark fringe to dark fringe), what is the wavelength of the light used?    nm

  Light of wavelength 520 nm falls on a slit tha l1x9 iucjjzl f37lf) 2 1b,zo2p6hfizt is $ 3.20\times10^{ -3}\;mm$ wide. Estimate how far the first brightish diffraction fringe is from the strong central maximum if the screen is 10.0 m away.    m

  A single slit 1.0 mm wide is illuminated by 450-n,h:a0dk- cdqasqz 5s9 m light. What is the width of the central maximum (in cm) in the9:dkhcza 0,sq asq-5d diffraction pattern on a screen 5.0 m away?    cm

  Monochromatic light of wavele4qp7b-j v wfx6,:r mbrqdn*q - .xanf40h/ bacngth 653 nm falls on a slit. If the angle between the first bright fringes on either side of th4x 0b.6 pbqnxdf7vrj q4f:hc- ban,*-qm /wrae central maximum is 32$^{\circ}\,$, estimate the slit width.    $\mu m$

  How wide is the central diffraction peak on a scrwfc sl0f) jm;7eftq10 een 2.30 m behind a 0.0348-mm-wide slit1flf0j ;70)fqecm sw t illuminated by 589-nm light?    cm

  When blue light of wavelength 440 nm falls on a singlenf2vei4y4 q fb w/rl .)h.vdf(m;d 9pt slit, the first dark bands on (bv)n;9p4 wh2firdeq ff. dtm/vl.4yeither side of center are separated by 55.0$^{\circ}\,$. Determine the width of the slit.    $ \times10^{-7 }\;m$

  When violet light of wavelength 415 nm falls on a single slit, it creakd 2:i dzli;y+tes a central diffra 2ild;+z iy:dkction peak that is 9.20 cm wide on a screen that is 2.55 m away. How wide is the slit?    mm

  If a slit diffracts 650-nm light so that the c/c+0kt g onu;ia4m 0rzj78ywfv f41 udiffraction maximum is 4.0 cm wide on a screenzig u+8 ccmn414ukyo0jfatr0fv w; 7/ 1.50 m away, what will be the width of the diffraction maximum for light of wavelength 420 nm?    cm

For a given wavelengtgrjk*2p*i0zvq3m w u (h $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm light produce a second-order maximumi u2/g 1kil(g9 .htqhx when falling on a grathg/qtg9 k2 xlh(. uii1ing whose slits are $1.45 \times10^{-3 }\;cm$ apart?    $^{\circ}\,$

  A $3500-line/cm$ grating produces a third-order fringe at a 28.0$^{\circ}\,$ angle. What wavelength of light is being used?    nm

  How many lines per centimeter does d abzx,f)s f;5a grating have if the third-order occurs at an 18.s,fzadx f)b 5;0$^{\circ}\,$ angle for 630-nm light?    $ \times10^{3 }\,lines/cm$

  A grating has $8300\;lines/cm$. How many complete spectral orders can be seen (400 nm to 700 nm) when it is illuminated by white light?   

  The first-order line of 589-nm light falling on a dt vrm1o i0 a r1wom1q.g:np5m( k:h*lpiffraction grating is observed pm0hpam:5r.t wokringo:(1m v11*lqat a 15.5$^{\circ}\,$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction gratiny1wya kysuiqy 1(r8jc(2 h*m0g has $ 6.0\times10^{ 5}\;lines/m$. Find the angular spread in the second-order spectrum between red light of wavelength $ 7.0\times10^{-7 }\;m$ and blue light of wavelength $ 4.5\times10^{-7 }\;m$.    $^{\circ}\,$

  Light falling normally on 37qjrl - p4 um wwlb5mt 3gd:1x29oxdka $9700-line/cm$ grating is revealed to contain three lines in the first-order spectrum at angles of 31.2$^{\circ}\,$, 36.4$^{\circ}\,$, and 47.5$^{\circ}\,$. What wavelengths are these?
$\lambda_{31.2}$    nm
$\lambda_{36.4}$    nm
$\lambda_{47.5}$    nm

  What is the highest spectral order that can be s60k0tgmh)je keen if a grating with 6000 lines per cm is illuminated with 633-nm laser light? Assume normal incidence.teh0g0k) kj6m   

  Two (and only two) full spectral orders can be seen on either side of thv(q0be:brg2 h o3tqiz2/lj4w e central maximum when white light is sent through a diffraction grating. What is the maximum number of/2g4 hboei3ljzt2r b(0qvw: q lines per cm for the grating?    $ \times10^{ 3}\;lines/cm$

  White light containing wavelengths from 410 nm to 750 nm falls- h+m.m06fntoi-kti b jxq28p 1v6n tg on a grating with xmq+68.g1tnp0n6 fikb oi- tm-t j2vh$8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which produces monochromatic light of a known waveleng;ztmb91y 8 ty t+xb.mrth $\lambda\;=\;6.328\times10^{-7 }\;m$ is used to calibrate a reflection grating in a spectroscope. The first-order diffraction line is found at an angle of 21.5$^{\circ}\,$ to the incident beam. How many lines per meter are there on the grating?    $ \times10^{ 5}\;lines/m$

  Two first-order spectrum lines are measure19e9/ +k1 nzebigycha d by a $9500-line/cm$ spectroscope at angles, on each side of center, of +26$^{\circ}\,$ 38$^\prime$,+41$^{\circ}\,$ 08$^\prime$ and -26$^{\circ}\,$48$^\prime$,-41$^{\circ}\,$ 19$^\prime$. What are the wavelengths?
$\lambda_{26.72^{\circ}}\;=\;$    nm
$\lambda_{41.23^{\circ}}\;=\;$    nm

  If a soap bubble is 120 nm thime1ketw n*zsx g5 j/57ck, what wavelength is most strongly reflected at the center of the outer surface when illuminated normally by white lx57gs5tew 1/ kmnzj* eight? Assume that $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark friw9wut zc0iu5pm *:gf ak,25 unnges in Example 24–8 if the glass plates are each 26.5 cf :*z59ak0gu 5mupinw uwc, t2m long?    cm

  What is the smallest thickness of a soap:d rqjvb473e7nerqwj; :dxd 8 film $(n\;=\;1.42)$ that would appear black if illuminated with 480-nm light? Assume there is air on both sides of the soap film. $t_min$    nm

  A lens appears greenish yellow+b l nfzjjk./j jg3.u +e5z.wr ($\lambda\;=\;570\;mm$ is strongest) when white light reflects from it. What minimum thickness of coating $(n=1.25)$ do you think is used on such a glass $(n=1.52)$ lens, and why? $t_{min}$    nm

  A total of 31 bright and 31 dark Newton’s rings (not )frqqmpyo,xzs 196 -t counting the dark spot at the center) are observed when 550-nm light falls normally on a planoconvex lens resting on a flat glass surface (Fig. 24–31x1 f- sqym,roqp6t9)z ). How much thicker is the center than the edges?    $\mu m$

  A fine metal foil separates u**tvlpx k5in e)p2o ,v w3i5zaq:/ umone end of two pieces of optically flat glass, as in Fig. 24–33. When light of wavelength 670 nm is inzpvl3) u/wi55: ,ioqtuv*ep*a mkx2ncident normally, 28 dark lines are observed (with one at each end). How thick is the foil?    $\mu m$

  How thick (minimum) should thyjy, eab d0rgc.3s81e e air layer be between two flat glass surfaces if the glass is to appear bright when 1 e3r,bs8 .0ecgjdyya450-nm light is incident normally?    nm
What if the glass is to appear dark?    nm

  vA piece of material, suspected of being )qemnuioh;(5 u9nz)z;p-8y xploj :ra stolen diamond $(n=2.42)$ is submerged in oil of refractive index 1.43 and illuminated by unpolarized light. It is found that the reflected light is completely polarized at an angle of 59$^{\circ}\,$. Is it diamond? ----待选择----yesno 

  A thin film of alcohol k)qkp/or-i ck-:k,a vm /.vrn$(n=1.36)$ lies on a flat glass plate $(n=1.51)$. When monochromatic light, whose wavelength can be changed, is incident normally, the reflected light is a minimum for $\lambda\;=\;512\;nm$ and a maximum for $\lambda\;=\;640\;nm$ What is the minimum thickness of the film?    nm

  When a Newton’s ring apparatus (Fig. 24–31) is imme25k lan+z:2qd kyhl hnd:98fsrsed in a liquid, the diameter of the eighth dark ring decreases from 2.9 szn y:8k2ldh52:hnf9d+ q kal2 cm to 2.48 cm. What is the refractive index of the liquid?   

  What is the wavelength-+z3z -akwvmr , yrru; of the light entering an interferometer if 644 bright fringes are counted wyzk -,;avw-r3+ r rzmuhen the movable mirror moves 0.225 mm?    nm

  A micrometer is connected to the movable:p gf pr- 3b*eqlotk3o3/fd5 8u0hlas mirror of an interferometer. When the micrometer is tightened down on a t uf33-/lrfeo05gk38hbdpqst p :o*l ahin metal foil, the net number of bright fringes that move, compared to the empty micrometer, is 272. What is the thickness of the foil? The wavelength of light used is 589 nm.    $\mu m$

  How far must the mirror jk:;xaco8jdk j.wsx,+0mc) ) +qrur n$M_1$ in a Michelson interferometer be moved if 850 fringes of 589-nm light are to pass by a reference line?    mm

  One of the beams of an interferometer (Fig. 24–59) passes ke ,i/,;4w 6fdor/pavjxpx5 x through a small glass container containing a cavity 1.30 cm deep.xxi,xj6k5r;4 /wdf/v,p o a pe When a gas is allowed to slowly fill the container, a total of 236 dark fringes are counted to move past a reference line. The light used has a wavelength of 610 nm. Calculate the index of refraction of the gas, assuming that the interferometer is in vacuum. $n_{gas}$

  

  Two polarizers are o,(eyyl4 +dxla riented at 65$^{\circ}\,$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s anq 3xk2ujx0yakzg 3 -x8gle for an air–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerged in water if the 8be/ jhaext-oqi s,*4 ;4nkn+isdxt/ light is hittin-4xqi;e8es /on xk+ d,hta/*ijt4n bsg the diamond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the light paswd3p 733ppbaqsing through them is a maximum. A 3q 7wabp3ppd3t what angle should one of them be placed so that the intensity is subsequently reduced by half?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be place5x+h7e-5j7xs l encay d so as to reduce the intensityxxn5y 7e- +h 5eslcja7 of the incident unpolarized light to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oriente1sz iguh3 5f4sd at 40$^{\circ}\,$ to each other and plane-polarized light is incident on them. If only 15% of the light gets through both of them, what was the initial polarization direction of the incident light?    $^{\circ}\,$

  Two polarizers are oriented at 3*e-iemcvvnfx7f( 0q, 8.0$^{\circ}\,$ to one another. Light polarized at a 19.0$^{\circ}\,$ angle to each polarizer passes through both. What percent reduction in intensity takes place?    %

  What would Brewster’s angle be for reflections off the surface7 phj :(mbicm4 of water for light coming from beneath the surface? Compare to the angle for total internal reb( im47:mpcjhflection, and to Brewster’s angle from above the surface.
If the light is coming from water to air, $\theta_{p}$    $^{\circ}\,$For the refraction at the critical angle from water to air $\theta_c$   $^{\circ}$ If the light is coming from air to water $\theta_p'$   $^{\circ}$

  Unpolarized light passes through five succesln2c1hu5rt t41jca;osive Polaroid sheets, each of whose axisu1h2oc5n t tcra1l4;j makes a 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength 1cumarzng42p6ab0d 3$ 5.0\times10^{7 }\;m$ passes through two parallel slits and falls on a screen 4.0 m away. Adjacent bright bands of the interference pattern are 2.0 cm apart.
(a) Find the distance between the slits.    mm
(b) The same two slits are next illuminated by light of a different wavelength, and the fifth-order minimum for this light occurs at the same point on the screen as the fourth-order minimum for the previous light. What is the wavelength of the second source of light? $\lambda_2$    $ \times10^{-7 }\;m$

  Television and radio waves refl x js;1 r4d-eesy9afh7qvo1i2ecting from mountains or airplanes can interfere with the dy1q jhxf2ssre4vi-7 o9e;a 1direct signal from the station.
(a) What kind of interference will occur when 75-MHz television signals arrive at a receiver directly from a distant station, and are reflected from a nearby airplane 118 m directly above the receiver? Assume $\frac{1}{2}\;\lambda$ change in phase of the signal upon reflection.  ----待选择----constructivedestructive 
(b) What kind of interference will occur if the plane is 22 m closer to the receiver?  ----待选择----constructivedestructive 

  Red light from three separate sources passes through a diffraction grating withn:qvo:3)+:on azj/ qvp a of(wj1fqp ,0hw(su jzvw) a w3oq :1s:oqo v/,p(h+:nfn(qaf p 0uj$ 3.00\times10^{5 }\;lines/m.$ The wavelengths of the three lines are $ 6.56\times10^{-7 }\;m$ (hydrogen), $ 6.50\times10^{ -7}\;m$ (neon), and $6.97 \times10^{ -7}\;m$ (argon). Calculate the angles for the first-order diffraction lines of each of these sources. $\theta_{h}$    $^{\circ}\,$ $\theta_{n}$    $^{\circ}\,$ $\theta_{a}$    $^{\circ}\,$

  Light of wavelength 590 nm 9 8j vte2i-6pzd*5xg tdsw4m jpasses through two narrow slits 0.60 mm apart. The screen is 1.70 m away. A second source of unknown wavelength pr ijg* we6tmp 48vdtdx-sz9 2j5oduces its second-order fringe 1.33 mm closer to the central maximum than the 590-nm light. What is the wavelength of the unknown light? $\lambda_2$    nm

A radio station operating at 102.1 MHz broadcasts from two identical antenx8yxdh7*rj8jk h k4 -dnae at the same elevation but separated by an 8.0-m horizontal distance d, Fj d-xry884 dk*hkxjh7ig. 24–60. A maximum signal is found along the midline, perpendicular to d at its midpoint and extending horizontally in both directions. If the midline is taken as 0$^{\circ}\,$, at what other angle(s) $\theta$ is a maximum signal detected? A minimum signal? Assume all measurements are made much farther than 8.0 m from the antenna towers.

  A teacher stands well back fro,xcuw/+ag; b .rsksx2m an outside doorway 0.88 m wide, and blows a whistle of frequency 750 Hz. Ignoring reflections, estimate at2/r,x;ks+.b ucsw agx what angle(s) it is not possible to hear the whistle clearly on the playground outside the doorway.    $^{\circ}\,$ either side of the normal.

If parallel light falls on a single slit qifx)p, m w8nx6je0o8of width D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a seriec2)6xf ol* 9vpqy8qlds of parallel lines across them. When normally incident 2xlpocqq6 8lfd *y v9)460-nm light is reflected from the wing, the wing appears bright when viewed at an angle of 51$^{\circ}\,$. How far apart are the lines?    nm

  How many lines per centimeter must a grating have if there is to be e2kj.4jt*h vvno second-order spectrum fov2jt .4 *jehkvr any visible wavelength?   $ lines/cm$

Show that the second- and third-order spectra of white light producv4dh-3 fcb9n zed by a diffraction grating always overlap. What wavzfc9vd4n 3-bhelengths overlap exactly?

  When yellow sodium lig9pght3fa .24xl h -vqxg7-b moht, $\lambda\;=\;$ falls on a diffraction grating, its first-order peak on a screen 60.0 cm away falls 3.32 cm from the central peak. Another source produces a line 3.71 cm from the central peak. What is the wavelength of the new source? How many $lines/cm$ are on the grating?
   nm
  $ lines/cm$

  Light is incident on a diffraction grating with and the patterf5:f /c0o pcmnn is viewed on a screen onc/ 0p ffm:5c2.5 m from the grating. The incident light beam consists of two wavelengths, $\lambda_1\;=\; 4.6\times10^{ -7}\;m$ and $\lambda_2\;=\; 6.5\times10^{ -7}\;m$. Calculate the linear distance between the first-order bright fringes of these two wavelengths on the screen.    m

What is the index of refraction of a clear material if a minimum wr ;sh9 5gysoa85c,9g7uo0 jg f9cirlof 150 nm thicknel;cgg9r5a85su0oh9i, 79o cjf wsygr ss of it, when laid on glass, is needed to reduce reflection to nearly zero when light of 600 nm is incident normally upon it? Do you have a choice for an answer?

  Monochromatic light of variabd p 499g9esuuble wavelength is incident normally on a thin sheet 9ubg 9 s4epd9uof plastic film in air. The reflected light is a minimum only for $\lambda\;=\;512nm$ and $\lambda\;=\;640nm$ in the visible spectrum. What is the thickness of the film $(n=1.58)$? [Hint: Assume successive values of m.]    nm

  Compare the minimum t+kwbk1y 7lak:hickness needed for an anti-reflective coating $(n=1.38)$ applied to a glass lens in order to eliminate
(a) blue (450 nm),    nm
(b) red (700 nm) reflections for light at normal incidence.    nm

  What is the minimum (non-i5*kqbjzc:g k f-9;xtzero) thickness for the air layer between two flat glass surfaces if tfbg5zq;9 xkj* t:k ic-he glass is to appear dark when 640-nm light is incident normally?    nm
What if the glass is to appear bright?    nm

Suppose you viewed the light tra-)+.x-wjc k)e)uaq cc 5cmo o:2wearunsmitted through a thin film layered on a flat piece of glass. Draw a diagram, similar to Fig. 24–30 or 24–36, and describe the conditions required for maxima and minima. Consider all possible values of index of refraction. Discuss the relative size of the minima compared to th aaw 5m.u jq: co) -x2oc)ecck+ewu-r)e maxima and to zero.
24-30
24-36

  At what angle above the horizon is the Sun when lighstj , qr1gnuo)k y5ed5 u:l3.ot reflecting off a smooth lake is pola,)n s eyt uqk 1l:djgo5u.r5o3rized most strongly?    $^{\circ}\,$

  At what angle should the axes of two 2dvqnl55l9 s 2d/qve f0c7o hpPolaroids be placed so as to reduce the intensity of the incident unpolarized light by an additional factor ( sd/9q72lqf5 0v5cvp2oedhl nafter the first Polaroid cuts it in half) of
(a) 4,    $^{\circ}\,$
(b) 10,    $^{\circ}\,$
(c) 100?    $^{\circ}\,$

  Unpolarized light falls on two polarizer shh y;u-0vkync(0eza;o0ao 3fi eets whose transmission axes are at right angles. A third polarizer ioe3zo(y0ink-h 0vf; uaa;0y c s placed between the first two so that its axis makes a 62$^{\circ}\,$ angle with the axis of the first polarizer.
(a) What fraction of the incident light intensity is transmitted?    $I_0$
(b) What if the third polarizer is in front of the other two?

Four polarizers are placed in succes fqii-o3 j2)ission with their axes vertical, at 30$^{\circ}\,$ to the vertical, at 60$^{\circ}\,$ to the vertical, and at 90° to the vertical.
(a) Calculate what fraction of the incident unpolarized light is transmitted by the four polarizers.
(b) Can the transmitted light be decreased by removing one of the polarizers? If so, which one?
(c) Can the transmitted light intensity be extinguished by removing polarizers? If so, which one(s)?

  A laser beam passes through a slit of width x(hqa wy cemd.q;6a;uw 4h *8h1.0 cm and is pointed at the Moon, which is appr cm*h 8y(e;a q.h ;wqxuwahd46oximately 380,000 km from the Earth. Assume the laser emits waves of wavelength 630 nm (the red light of a He-Ne laser). Estimate the width of the beam when it reaches the Moon.    km

  A series of polarizers are each placed -j:q )+oxol f(dk-1qv v lms4lat a 10$^{\circ}\,$ interval from the previous polarizer. Unpolarized light is incident on this series of polarizers. How many polarizers does the light have to go through before it is $\frac{1}{4}$ of its original intensity?   

  A thin film of soap o zbgg3s)*-g. yvemj )hp1rh7ioil -8dv ,9e s$(n=1.34)$ coats a piece of flat glass $(n=1.52)$ .How thick is the film if it reflects 643-nm red light most strongly when illuminated normally by white light?    nm

  Consider two antennas radiating 6.0-MHz 40z q d47t lfbkd1/rj *dp5isxradio waves in phase with each other. They are ls id5f *z j pd41r7txkq04bld/ocated at points $S_1$ and $S_2$, separated by a distance $d\;=\;175m$, Fig. 24–61. What are the first three points on the y axis where there will be destructive interference? (Destructive interference in this case means that a radio receiver placed at that point would pick up no signal).    m    m    m

  A parallel beam of light containing two wavelengths, 420 n(s v8z6r7gbp)o :hqu: 1jeept5hbe/b m and 650 nm, enters a silicate flint glass equit( / b8jb pop z5vu):6e:hbhrs1qee7glateral prism (Fig. 24–58).
(a) What is the angle between the two beams leaving the prism?    $^{\circ}\,$
(b) Repeat part (a) for a diffraction grating with    $^{\circ}\,$

  A Lucite planoconvex lens has one flat surface av47d1x did +s-c1t vkxnd one with $R\;=\;18.4\,cm$ It is used to view an object, located 66.0 cm away from the lens, which is a mixture of red and yellow. The index of refraction of the Lucite is 1.5106 for red light and 1.5226 for yellow light. What are the locations of the red and yellow images formed by the lens? [Hint: See Section 23–10.]
$d_{i-red}$    cm
$d_{i-yellow}$    cm