Does Huygens’ principle apply to sound waves? To wae0k9nf85n, 10rlx wk ,bvadrz d,awk9ter waves? Explain.

What is the evidence that ligh)71zvj7mfxp w w,zca -t is energy?

Why is light sometimes described as r k+tzi ao+r 4:0hxzlh43txk/ oays and sometimes as waves?

We can hear sounds arounw +*3 jozsp)gxd corners, but we cannot see around corners; yet both sound a* pz) ojx+s3gwnd light are waves. Explain the difference.

If Young’s double-slit experiment were submerged in water, how would the frin-( ovd7t8k ,xsq r-ynwge pattern be cw qrn o v-y-(8kts7dx,hanged?

Monochromatic red light is incident on a doublu)6 (6 ghxquuue slit, and the interference pattern is u)xuu qu6g6h( viewed 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 their pad,c31c:zu tx +upeze a.f4q*j th lengths differ by howeu *f4+jzq,tpd.zu1c eca3 :x much?

Why was the observation of the dodnoo 1e42.yh tzp2 h)qy:ebz3 uble-slit interference pattern more convincing evidence for the wave theory of light than the q2z2 : )ydzhbe .y3tpo n4oh1eobservation of diffraction?

Compare a double-slit experiment for sound waves to thnv **)v oay*3cpkn,ul at for light waves. Discuss the similarities ac,vy*3u**v )aknponl nd differences.

Why doesn’t the light from the two headlights of a distoe/vs )7)g.sp cacbg 6zgb3. iant car produce an interferab3s)is). /bg vgzcp.7g oe6c ence pattern?

Suppose white light fallsc9z u--lbclt4e p :zm0 on the two slits of Fig. 24–7, but one slit is covered by a red filter (700 nm) andlzc-mcpz- b:4e0 ut9 l the other by a blue filter (450 nm). Describe the pattern on the screen.

When white light passes through a flat piece k j m)fa/4j7 e9i lx2yk.id/uyoq/3ulof window glass, it is not broken down into colors as it is byedi/ ylljj)4 kqy/ xi mufo3/.kua 729 a prism. Explain.

For both converging and diverging lenses, discuss how the focal len,v+v+w p/(q.szy e ufzgth for red light differs from that ,fzy( v+ewvusqp+/.zfor violet light.

A ray of light is refracted through three different materials (Fs5 15l5 +zxq/poboyrsig. 24–55). Rank the materials according to their index of refractio/51sy+ lsqzx5rpob 5on, least to greatest.

Hold one hand close to your eye a zvjn h:ylsu y9es;;o4171m oznd focus on a distant light source through a narrow slit between two fingers. (Adjust your fingers to obtain the best pattern.) Descoyme o9sjn 1yulv;71;4h z:szribe the pattern that you see.

What happens to the diffraction patternk22kwpmcc 5x+qowia4 h :9ht( of a single slit if the whole apparatus is immersed in (a) water, (b) a vacu:kc cqtww4o5m kix a2 9p(hh2+um, instead of in air.

For diffraction by a single slit, what is the effect of increasingmlj,-v v hu:*o (a) the slit width, m -v,o:*vhjluand (b) the wavelength?

What is the differenc9q0a k(es dv:xe 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, wsbj4 vr 8xoi(*m6x5 lohat is the advantage of (a) many slits, (b) closely spa (v54ijos x*obxm 68rlced slits?

White light strikes (a) a diffraction grati4dipav o,akm:q(0 ob: ng, and (b) a prism. A rainbow appears on a wall just below the direction of the horizontal v ad: bp0akq:4omi, o(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 400 nm and 700 nm, inc+:/ cus:oggqh u3eji3ident normally on a diffraction grating, for what orders (if any) would there be overlap in the observed spectg:/3heg+3j usuc: q oirum? Does your answer depend on the slit spacing?

Why are interference fringes noticeable only for a thpzzx q+z 9/,hgmgrchvs1 ; yp3o/(j* xin film like a soap bubble andxx/9 chsmz* +vzrp1j;g(,hopzgyq 3/ not for a thick piece of glass, say?

When a compact disk (CD) is held at an :g,+,xv 8gil-am ;ftdbjl(kh angle in white light, the reflected light is a full tbhjv,xil8lf + ,g ;kg-(:d amspectrum (Fig. 24–56). Explain. What would you expect to see if monochromatic light was used?

Why are Newton’s rings (Fig. 2 ubt8ilyc)c,jj)inv rk dm)d yv367*94–31) closer together farther from the center?

Some coated lenses appear greenish yellow when seenb n7:;y4qyy ;mepurx + by reflected light. What wavelengths do you suppose the coating is designeb; q7myp;n:e4xr+y u yd to transmit completely?

A drop of oil on a pond appears bright at its edges, y0di aq4rg7sui0o 0 70s 7elgawhere its thickness is much less than the wavelengths of visible light. What can you say about the index of refr oa0ue s0iar syl7g0i 77d40gqaction of the oil?

What does polarizationf/lccyl3e rry. qn zg ,zn:x+2d0*8tv tell us about the nature of light?

Explain the advantage of polarized sunglasses ov djsg0g p91pmi ,uoo)(phh)jo g(r1* xer normal tinted sunglasses.

How can you tell if a pair of sunglasses is polarizing o ai6g3sni /1)2ze wyofr not?

Two polarized sheets rotated at an angle org5y9qd jv5 7gbo- lh;f 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 atmospuj7zxz6 tqd. +i.pe9ghere?

If the Earth’s atmosphere were 50 1gfl-ific;9 q times denser than it is, would sunlight still be white, or would it be some other fgliicq9-; 1fcolor?

  Monochromatic light falling on two gqh+ l5.tc2ul /mvtg ;slits 0.016 mm apart produces the fifth-order fringe at angv+ctl.utmqlg /h25; 8.8$^{\circ}\,$ angle. What is the wavelength of the light used?    $ \times10^{-7 }\;m$

  The third-order fringet0tnin*8 e8c::wwi yg go4)fk of 610 nm light is observed at an angle 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 0.04lr xu5 s2ved7,8 mm apart. Successive fringes on a screen 5.00 m away are 6.5 cm apart near the center of 5sx rvu,7ed 2lthe pattern. Determine the wavelength and frequency of the light.
$\lambda\;=\;$    $m$
$f$ =    Hz

  A parallel beam of light from a He-Ne laser;iwm4uam f;g(, with a wavelength 656 nm, falls on two very narrow slits 0.060 mm apart. mfg;;u4imwa (How far apart are the fringes 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 s+zg ur.3a. rho-(mdq0 cd(di2vvm x, an interference pattern in which the fourth-order fringe im u0d, r (qra+g2h.omv- sd3xc zd(iv.s 38 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 apdv18dz67 iv x5taprs4 ha.u/ ge-o/ zwart, how far apart are the second-order fringes for these two wavelengths on a screen 1.0 d4hzd .7/r-u ovtspxez1g6a 8vwa5/im away?    mm

  In a double-slit experiment, it is found that blue light of wavelengt qtqhzp)v oz s:)z5 ;il+vls+(h 460 nm gives a )vs:llq os+ tz5qhv;i zp z+)(second-order maximum at a certain 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 apart pass through two openings 5.d 6a5(j6x el+8m1we .9ugerkq c 4scdi0 cm apart in a board. At a point 2.0 m beyond the board, at what angle relative to the “straight-through” direction would there be re+ld u9(m1 ai e.4ekqc6cwd5x6 s 8gjlittle or no wave action?

Suppose a thin piece of glap0di(drh)w 65z9msvzf qt gj)7 i-d+hss is placed in front of the lower slit in Fig. 24–7 so that the two waves ente)-g70q+diz9 6d ti)fhvj5pmdswrh (z r 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, the third-order maximum fr;nhl4 mx,fckeli74 5 or 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 ce4rnklim4 , hfl x75;second-order maximum of this light be located?    mm

  Two narrow slits separated by 1.0 mm a/1uzv -m8mw0*aqmsb a re illuminated by 544 nm light. Find the distamv-1 q 0wmmua*8/ab zsnce between adjacent bright fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 nm in air falls on two *(gzha6 v ymbgn gpy03v /s6l.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 o 3w +mr7grc+gyt4 mh1ff a double-slit apparatus illuminated by 640-nm light. The center point on the sg71y++mw 4trc3fr gmh creen, instead of being a maximum, is dark. What is the (minimum) thickness of the plastic?    nm

  By what percent, approximate. u3jn rtv(l0t* idu5rly, does the speed of red light (700 nm) exceed that ofnr t*.j30tlvurud ( 5i violet light (400 nm) in silicate flint glass? (See Fig. 24–14.)    %

  A light beam strikes a piece of ggtv 5aqo o918wlass 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 two wavelengths,v)d2vcbmdr 7, $\lambda_1\;=\;450\;nm$ 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, what is the full angulhfz( hhp.1c++ wb4/ nk8qniri ar width o +piwcnqh.+/41 z(r kfh8ibnhf the central diffraction peak?    $^{\circ}\,$

  Monochromatic light falls on l9 ijfxg o w*8sfubs:1b :.mg: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 fallb4 6bi al8b:kzr 1hw b.eyoc52s on a slit 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 iso-/bx yzp-6a63 .s6 lw/csu ldtbkd v8mus2w1 illuminated by 450-nm light. What is the width of the central maximum (in cm) in the diffraction pattern on a scre6s ub 8w.szmuoldk2xwt -/ 1/6pv6lb3d sca-y en 5.0 m away?    cm

  Monochromatic light of wavelength 653 nm faw6bi h7qj 5lhpv. a+,flls on a slit. If the angle between the first bright fringes on either side of the central maximum is,fhh+5j ip l.7v baw6q 32$^{\circ}\,$, estimate the slit width.    $\mu m$

  How wide is the central diffraction peak on a screen8x 7t: 8q ,i1hs3so3fu bmlivtf:pp 7p 2.30 m behind a 0.0348-mm-wide slit illuminated by 589-nm lighp 8iob7m3 ipt, sh8:vq7ft1f 3upsl: xt?    cm

  When blue light of wavelength 440 nm falls on a single slit, the first dar 9gn fljmhr-0-ko b./ bm3.nftk bands on either side of center are mm9nhlk-g tf/b. bj. -on0fr3separated by 55.0$^{\circ}\,$. Determine the width of the slit.    $ \times10^{-7 }\;m$

  When violet light of wavelength 415 nm falls onjru**(wky ztyqj8bg ce+ 5h1)zm3mq0 a single slit, it creates a central diffraction peak that is 9.20 cm wide on a screen that is 2.55 m away. How wide is the slit?rc*w8j1y+jg3) mz kybqmh5tq* 0ze u(    mm

  If a slit diffracts 650-nm light so that the d /79dhgrff02 5nnihcziffraction maximum is 4.0 cm wide on a screen 1.50 m away, what will be the width of the diffr0z2h7cn/ 5 fgfni9dhraction maximum for light of wavelength 420 nm?    cm

For a given wavelength sgp(v3-uerxzb :cbo* 9 5ein9 $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm light t+t es7zu4:jcs u b bx80)/sgbproduce a second-order maximum when falling on a grating whoz4 +uj:t87bg u0b csx/)btessse 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 a grating have if the t3yzgyqy/l paa oz5*n1)/9w w bhird-order occurs at aaq zlwnoa/1 y5y)/pb9*y3zw g n 18.0$^{\circ}\,$ 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 grfq g3 f)5v ge:w4xmxt9ating is observed at a 1t5:x xgvw f3)fq49meg 5.5$^{\circ}\,$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction grating z 10(y63fsagr a;zownhas $ 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 normalxauu0 kehw.62 ly 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 gku;mdq + /akd+rating with 6000 lines per cm is illuminated with 633-nm lmdad/ q+ k+k;uaser light? Assume normal incidence.   

  Two (and only two) full spc-t 3j*jc0k jfectral orders can be seen on either side of the central maximum when white light is sent through a diffraction g03jktfcj cj-* rating. What is the maximum number of lines per cm for the grating?    $ \times10^{ 3}\;lines/cm$

  White light containing wavelengths from 410 nm th0o ccp1 w.ez- d(7 1v,mygh haz4fqh j;.o7yco 750 nm falls on a grating with vajmdphg( .hz,7 oeqz1c 70c w-;yhhy1 4.c of$8500\;lines/cm$ 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 wavelength si (2i17 izvdz$\lambda\;=\;6.328\times10^{-7 }\;m$ 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 measureq*ncsh )uclc ; 0,llu6 d4;ucqd 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, whazsuhj 1;9orz(op d3r4o cq3k6t wavelength is most strongly reflected at the center of the outer surface when illuu361 o9z ro ods(4;pzr 3kjchqminated normally by white light? Assume that $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringes in Example 24–8 if the glass plates are ey64jof;e, lx7kkn6d h+ua; cxach 26.5 cm long? 6jhu ,4oy+6eca;k kxnf d7;xl   cm

  What is the smallest thickness of a so7-o3/opqra8qgyv8 enb ,lzq, ap 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 greenishl : ggkv5l(ln: ;y5vzi yellow ($\lambda\;=\;570\;mm$ 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 counting the dari:0 5c; d c.cqoxqf4afk spot at the center) are observed when 550-nm lfcccda q.4xo:;5q i0f ight falls normally on 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 ofypt,mit rd7- . two pieces of optically flat glass, as in Fig. 24–33. When light of wavelength 670 nm is incident normally, 28 dark lines are obttpm7,ridy . -served (with one at each end). How thick is the foil?    $\mu m$

  How thick (minimum) should the air layer be betw 3 fqfay wf;d73qtf/ea5d-ti 0een two flat glass surfaces if the glass is to appear bright when 450-nm light is incident n -tqad053yf/fdf ae;f7t 3qiwormally?    nm
What if the glass is to appear dark?    nm

  vA piece of material, suspected of being a stolen diamond 0waw qw1p1 vj4$(n=2.42)$ 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 uegw/b+ej;lh94 , qp j$(n=1.36)$ 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 immersed in a liquid, nfun1 2 g/ l-mxjh*gl5gjf.* g6ptui5 the diameter of tux5 *i 5tn uj1g- lmgg2 p*flg/nh6f.jhe eighth dark ring decreases from 2.92 cm to 2.48 cm. What is the refractive index of the liquid?   

  What is the wavelength of i-qx0)nzi* zjcu*j-(f gl+ yrthe light entering an interferometer if 644 bright frinjljnzqyzu -*cf i 0r*i)g -(+xges are counted when the movable mirror moves 0.225 mm?    nm

  A micrometer is connected to the movable mirr*1wd 956 btk: vdy f2yp2vaeyior of an interferometer. When the micrometer is tightened down on a thin metal foil, the net number of bright fringes that move, compared to thyevtv1yayd5 2w 2p*6:bkfid9 e 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 c 8.1 eeba8pgj$M_1$ 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 -3g4acyrms;yb1f q z) interferometer (Fig. 24–59) passes through a small glass container containing 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 interqyszca 13ym )4bfg ;-rferometer is in vacuum. $n_{gas}$

  

  Two polarizers are oriented amkaj4l7z-z w3 t 65$^{\circ}\,$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s angle f)mi ,h;pc:ie um,g/wg or an air–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerged in water ifj0g; l,pvcin ngl 4,cwq(k9 c+ the light is hitting the d+ cnjp,(qi ,c;w 0lng4gv9kcliamond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the light p 5(cw rjvj9hil 8:n5cqn 8a6iiassing through them is a maximum. At what angle should one of them be placed so that the in8:qjhjw55 ii8n 6 cv9li(arcntensity is subsequently reduced by half?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so as to reduce the ine.rjei 987-:ogpckm btensity of the in k9ce-i8p e.rog:jb7 mcident unpolarized light to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oriented 7b37liq ny2z wat 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 xctz5b7 /e7sr z,tkbu2 5t6zo38.0$^{\circ}\,$ 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 fopjdgal(x4te ih; :ly(lu ;q;( r reflections off the surface of water for light coming from beneath the surface? Compare to the angle for t:;hjl;xydglu(;ta q(p iel( 4otal internal reflection, 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 successive Polaroid sheets, each of w/6f8lcvu3e7p gw6 6atrt evw1hose axis mpwvw 6371vert l8efg /c66u atakes a 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength vne fdugc /a+1,dyp y5e4 e9l2$ 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 refleckqwig::)d kxo 2xx59 tting from mountains or airplanes can interfere with the direct signal from the statio: kti92xx dkgxw): o5qn.
(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 y*7 nxg0qc)ke grating with qe7ky 0)* gxnc$ 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 pa3qd kj jllrr g3sc0+-2sses through two narrow slits 0.60 mm apart. The screen is 1.70 m away. A second source of unknown wavelength produces its second-order frin j3sgr0 - 3qcjk2+rlldge 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 8pnfnaohi7 dft;s8/z y .,us0 two identical antennae at the same elevation but separated by an 8.0-m horizontal distance d, Fig. 24–60. A maximum f;88zdasniso,y 70/up.n fh tsignal 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 from an outside doork v f(6jfia59*s buei;way 0.88 m wide, and blows a whistle of frequency 750 Hzek95(jvf*i bafius6;. Ignoring reflections, estimate at 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 of ws5 aw,5 xb:xididth D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a series of parallel lines fmcdn;h4oqo cd s(oa dwn 30(1g7 2e+wacross them. When normally incident 460-nm light is ona ng4 m;o(dco e(dch+ f017w q2w3dsreflected 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 nw z-0t+ki3 npio second-order spectrum for any vi 0kt-z3ipwn +isible wavelength?   $ lines/cm$

Show that the second- and third-order spectra of5lo*zhz1rp gzp i,pd5rd*:ds3u - s 8a white light produced by a diffraction grating always overlap. What wavelen5dus:r,1l* pz5p8pgd iz z-3aho*sdr gths overlap exactly?

  When yellow sodium lighl1v*6olqoa 8enl s(cmu6-p /rt, $\lambda\;=\;$ 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 gr0 ftli*(6s horating with and the pattern is viewed on a screen 2.5 m from the grating. The incident light beam htr6osi*f(l 0consists 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 rur+* xkc(n s4: l78mapshp+lsefraction of a clear material if a minimum of 150 nm thickness 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 c8h:ns 4 slps7(amk *xc++p urlhoice for an answer?

  Monochromatic light of 7h5 ur b.f.xrrvariable wavelength is incident normally on a thin sheet of plastic film in air. The reflected light isrfr5 u. h7x.br 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 an anti-reflect3j*ocpt(k z t)kfv2k ;ive 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 layu.h.mrz2f; p ,w(9f,vv(o ych nsb-ds er between two flat glass surfaces if the glass w,fz9( shnfmbu..pvcr , dvy hs (2;o-is to appear dark when 640-nm light is incident normally?    nm
What if the glass is to appear bright?    nm

Suppose you viewed thqko-0yzhz04c )i;zp 8kz k5ute light 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 the minima compared to zz k40u5-z0)qyzohk ct ik;8pthe maxima and to zero.
24-30
24-36

  At what angle above the horizon is the Sun when light reflectin)k0v*b g x)ywboj xv,j6twu: (g off a smooth lake is polarized0 ob,xugjv)w(yx* w :b)k6j tv most strongly?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so as to reduce theyr;-w8iv q(8/e0 xpdyp5ztld intensity of the zq-yli5r8xp dtv wd8y (;p0/e incident unpolarized light by an additional factor (after the first Polaroid cuts it in half) of
(a) 4,    $^{\circ}\,$
(b) 10,    $^{\circ}\,$
(c) 100?    $^{\circ}\,$

  Unpolarized light falls on two polarizer sheets whoseh wtb8av:b2 y/ transmission axes are at right angles. A third polarizer is placed between the first two so that its axis y8 va:bwtb2/ hmakes 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 success.sa mg-r*10j lc9kgii ion 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 1.0 cm and is pointed at the Moonaiuse1 6x -nj*.1pdwt , which is approximately 380,000 km from the Eart6spauj-*n dxe.1it w1h. 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 at a j u5;*y ziajdoy4gh25e8 wys m+9:ssh1/sibm10$^{\circ}\,$ 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 hw1o )xb ri*ao-mri5m 0vd:e* $(n=1.34)$ 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 radio waves in phase with bt4z1 krk3gp j j/.4gweach other. They a4wt4zkk1pg 3 jr/jg.bre 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 light containing two wavelengths, 420 nm and n6fu ozczq, llx:9;: w650 nm, enters a silicate flint glass equilateral prism w: z,o ql;l:9xz6un fc(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 andgecni2 32 smjrxpm,69 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