Does Huygens’ principle apply to sound waves? To water waveso0u 46nuu ee5k? Explain.

What is the evidence that 6txv nq px8sa.n( 5h;i3nsa9qlight is energy?

Why is light sometimes described 9f4x6y0c .tltv pgf2j as rays and sometimes as waves?

We can hear sounds around corners, but we cannot see around corners; yet both soase(j 1 0 a+3d:3.rnsmmk4krxcv4boy und .km+ v( 1ko sej3n4rabr 0:yx3s4dmcaand light are waves. Explain the difference.

If Young’s double-slit experimen):t m zwe- a2vdssh2b3t were submerged in water, how would the fringe pattern be changet2bzswem d)a3:sh2 - vd?

Monochromatic red light is incident on a double mn6kfl 14p +g cwfq24nslit, and the interference pattern is viewe 1+nn pf qgk6cfwl244md on a screen some distance away. Explain how the fringe pattern would change if the red light source is replaced by a blue light source.

Two rays of light from the same source destructively interfere if thpf65+n xllg .zf;r j6+bc-v toeir path lengths differ by how much z;f.+v6cn+56tor-j lpx gflb?

Why was the observation of the double-slit i; /8dr8rt8xn jx rwe)gf2vi2 :zn)jh rnterference pattern more convincing evidence for the wave theory of light than the observation ;)hnxx8nwrt:jd re) fri8zg 282rv/j of diffraction?

Compare a double-slit experiment fk/ ezn2r71m +tgh5ql por sound waves to that for light waves. Discuss the similarities and differenceelk /5nm1q hr2p 7gt+zs.

Why doesn’t the light from the twi q3pk8re3ve 1o headlights of a distant car produce an interference pattern?e 3i1ev3kprq 8

Suppose white light fallv5wi l,rw/4vd5t 46cz y 8rvurs on the two slits of Fig. 24–7, but one slit is covered by a red filter (700 nm) and the other by a blue filter (450 nm). Describe the pattern on the scri 5vcvt4vr /u68rw yr, 5wd4lzeen.

When white light passes through a flat piece of window glass, it isul(g y6eiu4epi4* 2ek not broken down into colors as it is by a prism. Explaekygeulu 246p(4i* eiin.

For both converging and diverging lenses, discuss how the focal lengtha ; +clnuym *at+/lpy c;n3r.;cad0 ey for red light d ;/n yalcapycn0lc.;*ae3tm+ dru ;y +iffers from that for violet light.

A ray of light is refracted through three different materials (Fig i-:* nwrox5qh8l6(my(x uacugq7 c z3juba-8. 24–55). Rank the materials according to their index of refraction, least to 6zuaxqn uj -- (c8g8w: (7 lhxmyo*3 carib5uqgreatest.

Hold one hand close to your eye and focus on a distvaf3q*s td*o -+sxagnts.2 g/ant light source through a naas- gdqv*s. 3f2no+at*s xg/trrow slit between two fingers. (Adjust your fingers to obtain the best pattern.) Describe the pattern that you see.

What happens to the diffraction pattern of a single sli pz2h(t2xn*r y ik5s/wt if the whole apparatus is immersed in (a) s5twknrph 2i (*z2yx/water, (b) a vacuum, instead of in air.

For diffraction by a single slit, what is the e jg9kt;0qg+fcffect of increasing (a) the slit width, and (gk;+g t9f0q cjb) the wavelength?

What is the differencepiin1,vctv c0zw 8 hi2ne29x+ in the interference patterns formed (a) by two slits $^{-4}\;cm^2$ apart, (b) by a diffraction grating containing $10^4lines/cm$?

For a diffraction grating, what is the advantage of (a) many slits, (b) close 4; k2ccc-pfwhz w(d) 8cn1q gzn2c4rily space4 hkcz8gqd4n2cc ) p-;c z21(wiwncrfd slits?

White light strikes (a) a diffraction grating, and (b) a prism. A rainbow appear(-wjpku)a wmfnw o3lsg,6, 5ee. 9duws on a wall just below the dir 3)(m -weo wepuk .a, 956fusnwwdgjl,ection of the horizontal incident beam in each case. What is the color of the top of the rainbow in each case? Explain.

For light consisting of wavelengths between 400flqjde/n;9l 6 nm and 700 nm, incident normally on a diffraction grating, for what orders (if any) would there be overlape6jld/ 9qln; f in the observed spectrum? Does your answer depend on the slit spacing?

Why are interference 7rxbyv ;w1-ea fringes noticeable only for a thin film like a soap bubble and y-1xbvr;7a ewnot for a thick piece of glass, say?

When a compact disk (CD) is held at an angle inu)8c ao9e fm:i8isq8 o white light, the reflected light is a full spectrum (Fig. 24–56). Explain.i 8uo os8 ):fa9mecq8i What would you expect to see if monochromatic light was used?

Why are Newton’s ringu9z / 9kax6nwgs (Fig. 24–31) closer together farther from the center?

Some coated lenses appear ,:ubu4viru0 grj0wm6i7z0xj greenish yellow when seen by reflected light. What wavelenmw,jxgr4iu7uv0 ib u6z :0 j0rgths do you suppose the coating is designed to transmit completely?

A drop of oil on a pond appears bright at its edges, where its thickness is8jsix y qb6.1u+e gg9ug(3 jwy much less than the wavelengths of visible lightubj yxg e6.+3wyj s(q8g9i1ug. What can you say about the index of refraction of the oil?

What does polarization tell us about the nature of lightd10 rq.)xgofj?

Explain the advantage oe4 8xc 7nrht:uf polarized sunglasses over normal tinted sunglasses.

How can you tell if a pair of sunglasses is polarizing or /26 ei* f8m h2zhpka2+eq 1lwndwo *ionot?

Two polarized sheets rotated at an a iegx() efq)q3ngle 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 color of the sky if the Earth had no atmodlh; (-5vbd wgsphere?

If the Earth’s atmosphere were 50 times den z )m1r/cc gismhb7dt8dm2q(9ser than it is, would sunlight still be white, or would it be some omim2s78 m qgz(hdc9td/1rcb)ther color?

  Monochromatic light falling on two slits 0.016 mm apart producesepm60e66-dm1avs9 -f1xz b 1cr tqiul the fifth-order fringe at an 8 z16 1-vc-1q96ifdxtpumlere sb60ma.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 angle of pgmwk2b 59) 26gk ukl7g jx.nx18$^{\circ}\,$ when the light falls on two narrow slits. How far apart are the slits?    $\mu m$

  Monochromatic light falls on two very narrowtf8w;gv8r y3whv l b77 slits 0.048 mm apart. Successive fringes on a screen 5.00 m away are 6.5 cm apart near the center of the pattern. Determine the wavelenlb hv 8r3y7wtw8v;f7g gth and frequency of the light.
$\lambda\;=\;$    $m$
$f$ =    Hz

  A parallel beam of li 98bd hyw8nif,ta0v0 aght from a He-Ne laser, with a wavelength 656 nm, falls on two very narrow slits 0.060 mm apart. How far apart are the fringesh ba0w id,n8 v98ayt0f in the center of the pattern on a screen 3.6 m away?    cm

  Light of wavelength 680 nm falls on two slits and produces an interferwas +rx fh380eence pattern in which the fourth-order fringe is 3e+08 fsw x3hra8 mm from the 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 two slits 0.58 mm apart,hzv-b )vx bq89 how far apart are the second-order fringes for these two wavelengths on a screen qxv b9) -v8zbh1.0 m away?    mm

  In a double-slit experiment, it is found thab o9k6d2w-ym w6y 1yvkt blue light of wavelength 460 nm gives a second-order maximum at a certaimvy-1bo6kkw d w y26y9n location 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 apartasmoon; kz (1) pass through two openings 5.0 cm apart in a board. At a point 2.0 m bs( ) a1ok;nozmeyond the board, at what angle relative to the “straight-through” direction would there be little or no wave action?

Suppose a thin piece of glass is wr. mq-k5h,yg placed in front of the lower slit in Fig. 24–7 so that the two waves enter y.qmwrg-hk5 ,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 experime)yaxb,+vq ) p2 kr2dgl::o 0xrw2cz nint, the third-order maximum for light of wavelength 500 nm is located 12 mm from the 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:2nr:l+b xq grxpya2kdv)wi )o2c ,z 0?    mm

  Two narrow slits separated by 1.0 mm are illrgwqd7mxyyi6 c7sr3u7kv, 35uminated by 544 nm light. Find the distance betw 5rr7 dv33wkymxu7,c6 i gqys7een adjacent bright fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 4r.1vhgw ;wi)mdoi+q z xz75s6/frwq; 80 nm in air 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 plastz,v exc/96 j ;p0k)gi2tud rtbfr f3x:ic (n=1.60) covers one slit of a double-slit apparatus illuminated by 640-nm light. The center point on the screen, instead of being a maxr, z6)3k ;cpxdtt9 2 e 0r/vfxgufijb:imum, is dark. What is the (minimum) thickness of the plastic?    nm

  By what percent, approximately, does the speed of z5a2 *,9gdubap f ;rpvykh:5lred light (700 nm) exceed that of violet light (400 nm) in silicate fkp;f a:,5vyrpul*2bd gz a59 hlint glass? (See Fig. 24–14.)    %

  A light beam strikes a piece of g *fn7oo9-jver /tad .slass at a 60.00$^{\circ}\,$ 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 containing tyvj30a*rekgn,:7g-9 o h qcilwo 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 0.0440 mm wide, wh.u wso7:tmd h+u5u v9a*d1 t)jnn1qauat is the full angular width of the central diffraction peau1v:u9d 1qu5m uh*)7awn oa s.+jtdt nk?    $^{\circ}\,$

  Monochromatic light faj/fqng ys8 b*ez:ob*cd:l9*y lls on a slit 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 slitswrk 3*i )h-glzv mu0( that 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 illuminatb-q3xn u j hihafg++7*ed by 450-nm light. What is the width of the central maximum (in cm) in the diffraction pattern on a screen 5.0hj- + nx3a7hibu+fq* g m away?    cm

  Monochromatic light of wavelength 653 nm falls on a slb 401x9eas3 e alxyc6wit. If the angle between the first bright fringes on eithexs4a b l3a906yx 1cweer side of the central maximum is 32$^{\circ}\,$, estimate the slit width.    $\mu m$

  How wide is the central diffraction peak on a screen 2.30 m behind a 0.034r*dal 1+ chje:8-mm-wide slit ic1+ler* :haj dlluminated by 589-nm light?    cm

  When blue light of wavelength 440 nm falls on pw*3pu4gi-fkq8oey a: ;,guv c(ve: z a single slit, the first dark bands on either side of center are f;ucy, ug4:pg pi3 v(8zvwak-e:q oe* separated by 55.0$^{\circ}\,$. Determine the width of the slit.    $ \times10^{-7 }\;m$

  When violet light of wavelength 415g* omg9;0xqby d,)k mg nm falls on a single slit, it creates a central diffraction peak that is 9.2bdm ;,o9x0*gkm ) gqgy0 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 thebs)n,w qxs ,s+ diffraction maximum is 4.0 cm wide on a screen 1.50 m away, what will be the width of the diffraction maximum for lb s+,nsqwx,s)ight of wavelength 420 nm?    cm

For a given wavelengthkccu7ku6)0.mgmoy ik9mzfk- fu)/ 6n $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-.kvkzb7m-i x 476ellknm light produce a second-order maximum when falling on a grating whose slits akl 74ez.-7b 6mxivkk lre $1.45 \times10^{-3 }\;cm$ 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 a gratingirz 17kh ujr; ov(i;5g have if the third-order occurs at an (1u5j; gr;ozviki 7hr18.0$^{\circ}\,$ 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 diffraction grat7xg+ m(l*eiwn) 6fw wzqxf9p6ing is observedxn lf6 ie wmpg)6+7qw(f9z*xw at a 15.5$^{\circ}\,$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction grating ngz,-:,di0 fmp kdzm.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)t-t/nw azjj +mun(4c on a $9700-line/cm$ 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 seen if a gnkx(z z 6 /bcafayml9,xih817rating with 6000 lines per cm(9f ,ma/7znxa8y1 xlb iz6hck is illuminated with 633-nm laser light? Assume normal incidence.   

  Two (and only two) full spectral orders cah26df.rs g djufxnykjx/45(1 n be seen on either side of the central maximum when white light is sent through a diffraction grating. What is the maximum nu/r16(j 4 usg .fy2xdjdxfnkh5 mber of lines per cm for the grating?    $ \times10^{ 3}\;lines/cm$

  White light containing wavelengtflsjn* 6yg- z)hs from 410 nm to 750 nm falls on a grating with ynj s6) *zglf-$8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which produces monochromatic l4sby4drtr/+fvq uk 0ojcob5bi;:ubs o80; t6ight of a known wavelength $\lambda\;=\;6.328\times10^{-7 }\;m$ 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 line x0tgg3cu nv8.+0pt res are measured 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 thick, what wav3 urwc h.s8)gt*dsq e9elength is most strongly reflected at the center of the outer surfacregt8)d9h .* q uswcs3e when illuminated normally by white light? Assume that $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringes in Example 24–juy2 639 pmsmpsrbj8: 8 if the glass plates are each 26.5 9p msjy3br j2p:us68m cm long?    cm

  What is the smallest thickness of a soap film oo0u a)y0+owx , kr(id+wfuf w y*.fm9$(n\;=\;1.42)$ 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 yello qpnj n :3.n3.ja.drpcw ($\lambda\;=\;570\;mm$ 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 ringsg89gif:ynvz,eet3*d e 1in m 9 (not counting the dark spot at the center) are observed when 550-nm light falls normally enei z 3 f,gi8t:d*1 ymve9g9non a planoconvex lens resting on a flat glass surface (Fig. 24–31). How much thicker is the center than the edges?    $\mu m$

  A fine metal foil separates one end of two pieces of4 3e 3)gbkw1 4tqnjjfk optically flat glass, as in Fig. 24–33. When light of wavelength 670 nm is incident normally, 28 dark lines are observed (with one at each end). How thick is thejfn )jq bgw443t ke3k1 foil?    $\mu m$

  How thick (minimum) should the air layer be bemup9j-g0ma;0z uh oer dzs0 49tween two flat glass surfaces if the g- s0zmagzdu p ro;u0m9j40 9ehlass is to appear bright when 450-nm light is incident normally?    nm
What if the glass is to appear dark?    nm

  vA piece of material, suspec7c2p . - 4ihxp89ngetwe0e istted of being a 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 alcohojl4gnss8ga1a +e6 a p-l $(n=1.36)$ 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) 97 j ;bq6hsvygis immersed in a liquid, the diameter of the eighth dark ring decreases fr 96bhs7;yjqgv om 2.92 cm to 2.48 cm. What is the refractive index of the liquid?   

  What is the wavelength of the light entering an interferometen fnh;qz.ohms;u k*+r w s3*7ir if 644 bright fringes are counted when the mova* rk*f+ ;hun7w zhisn3msq.;oble mirror moves 0.225 mm?    nm

  A micrometer is connected to the m0kc r2d5ms m+mt ffb13m qb4y8ovable mirror of an interferometer. When the micrometer is tightened down on a thin metal foil, the net number of bright fringes that move, compared to the empty micrometer, is 272. What is the thic+fb4 cmd283qby0 m m 1trs5mkfkness of the foil? The wavelength of light used is 589 nm.    $\mu m$

  How far must the mirrorumi.w6 r0.;jcmsb i *u $M_1$ 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 interferomey(6ib2b9dmlm a q yg4+ter (Fig. 24–59) passes through a small glass container containiq l96ibdm2yag(+ bym4 ng a cavity 1.30 cm deep. 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 orie 2paynwlq,q-k: 8vm;xs 7n)mnnted at 65$^{\circ}\,$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s angle for an air–gyv .l0 3g)xlcolass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond s14:yg+vw qzjy3i; zx;n4spu submerged in water if the light is hitting the dia 1 x j4i +uzvzy3sysw4p;q:n;gmond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are alignuyrq4 1a(x28 i enxz,ned so that the light passing through them is a maximum. At what angle should one of them be placed so that the intensity is subsequently reduceezni4uy2, 1a8qr xxn(d by half?    $^{\circ}\,$

  At what angle should the axes of t-.c: bjed+(*gb we xwlwo Polaroids be placed so as to reduce the intensity of e beg+cdwx(lw-j.: b *the incident unpolarized light to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oriented at 9kn 8lxydlw/ ,3vu.vuf tus)zv*;/ qt40$^{\circ}\,$ 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 or dgc zf(88w8cyiented at 38.0$^{\circ}\,$ 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 ofznj2j6y* jf /0hq6gp mf the surface of water for light coming from beneath the surface? Compare to the angle for total internal reflection, and to Bg/ jnmp6 fqjj06z*hy 2rewster’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 successive Polaroid sheets, each of wh0 dq*gor 1y+qrzkvac +j+ep2aj i.-k*ose a *2a0k1aqqrjjod vzc+yk +.pe-gi*r+ xis makes a 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength xpr-64z d pr5u)fj8q( 65aharu1 bssb$ 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 reflecting from mountains or airplanes 5q+ s x2y -,cbdtzd7ogcan interfere with the direct signal from the d 5+otzxb,s7 q2cg d-ystation.
(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 g8d3sz(.eb :0 lwk2obm3o +xlg itg:fpasses through a diffraction grating with : eg2 .i0l:f3s(gkmdbo3xgzw lo+tb 8$ 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 passes td hyabh f6:vh5,4,r oohrough two narrow slits 0.60 mm apart. The screen is 1.70 m away. A second source of unknown wavelength produces its second-order fringe 1.33 mm closer to the central maximum than the 590-nm light. Whafao65 h dr:,b h4h,yovt is the wavelength of the unknown light? $\lambda_2$    nm

A radio station operating at 102.1 MHz broadcasts from two idze /xnafuf; 3tx /pjm4i.q g.w(.x xk:25 hgksentical antennae at the same elevation but separated by an 8.0-m horizontal distance d, Fig. 24–60. A maximum signal is found along the mid3zu. .jqs.(ha 4/; ge:x/2 wxkxp kfgftxi5mnline, 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 from an outside7t d6-p:w: j ic y6qmm1tfd3lz doorway 0.88 m wide, and blows a whistle of frequency 750 Hz. Ignoring reflections, estimate at what angle(s) it is not possible to hear the whistle clearly on the playgroun dmj6f md3y-w:l ctq:pzti 671d outside the doorway.    $^{\circ}\,$ either side of the normal.

If parallel light fallvzf.7b uso/ gy(hd 3s4s on a single slit of width D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a s,lulm+p2hh-9kl7 ro: md 4:sbpb xtw3 eries of parallel lines across them. When normally incident 460-nm light ilbdb, k- +l2u7xh:lt9p 4:homw p 3smrs 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 9rc *svpdaug9hn;jpn 72+qi *a grating have if there is to be no second-order spectrum for pjr as7+g2uq n*hpd9*;cin9 v any visible wavelength?   $ lines/cm$

Show that the second- and third-order spectra of white l9i 2zro th76vywmhs46ight produced by a diffraction grating always overlap. What wavelengths overlap exa s4yt9vow6 zhr2h67mictly?

  When yellow sodium lag *rdb+gc.gy)i 8)r cight, $\lambda\;=\;$ 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 dig4 +erw0k 3d.gt4qph zffraction grating with and the pattern is viewed on a screen 2.5 m from the grating. The incident lighqhpre+0 gd .43g tz4kwt 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 of +tut9i) nd 5l z:k3vco150 nm thickness of it, when laid on glass, is needed to reduce reflection td3n kz5it:uclv+o9) to nearly zero when light of 600 nm is incident normally upon it? Do you have a choice for an answer?

  Monochromatic light of variable wavelength is incident normally on a thm3 -f-mr5v4ja7 a*jyez gl-rgin sheet of plastic film in air. Tel43* rfyz jm-a -rm5j gva7g-he 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 thickness needed for 0b2/y tj d7 pwmlw*q3oyj /gg3an 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-zero) thickness for the air layer be*6hdas qqi3;a-5rkm ftween two flat glass surfa-qm qfka3*rd6 5s; aihces if the 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 g54 wokq:26kwpsws6 g74 btnglight transmitted 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 g4wb2n 5 6wqw sk4po:6gtsg7k the minima compared to the maxima and to zero.
24-30
24-36

  At what angle above the horizon is the Sun 9bk;cy2jvbzzwb-3ud (+m9qw* v0 g nkwhen light reflecting off a smooth lake is polarized most strojmd k2 bbwu*q -93 n( v+z;kwcbgz9vy0ngly?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so qq.t8d 1+oiijs.l7 f cas to reduce the intensity of the incident unpolarized light by an7. tj+qi is1l8.ofcd q additional factor (after the first Polaroid cuts it in half) of
(a) 4,    $^{\circ}\,$
(b) 10,    $^{\circ}\,$
(c) 100?    $^{\circ}\,$

  Unpolarized light falls o u;26 , :vds1+7m84bmdcp0qsd hzx7rzjpvyevn two polarizer sheets whose transmission axes are at right angles. A third ue vrmh7+xysdbq :40 82zp ,v6c 7md1zvj p;dspolarizer is 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 sutau/x 2s1 lhop3)ntt6ccession 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 srquf:3t,50u4dw c qtz lit of width 1.0 cm and is pointed at the Moon, which is approximately 380,000 km from the Earth. Assume the laz4,5 d :r0u3quc qtftwser 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 exby3+ -gp oy 2os8jmvi/i97rtach placed at 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 w/:-esmj*i *mya jek+$(n=1.34)$ 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 ra -mfirlj 1:9;zkhv s*l(yn zt.dio waves in phase with each other. They l ksl*ir-:z(9zytfh. 1jmnv ; are located 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 ligx5p /iftu2g4s ht containing two wavelengths, 420 nm and 650 nm, enters a silicate flint g5 4igpuft2sx/ lass equilateral 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 a) 69xv pp/hoy;ixjwtly(3z 0t0 h 0zwxnd 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