Does Huygens’ principle apply to sound waves? To wate( sc41 6n+s4wkzsnsp or waves? Explain.

What is the evidence that light is eyn. w gxhbj)c126yhq3nergy?

Why is light sometimes described as l t2pe3/m9sb zrays and sometimes as waves?

We can hear sounds around corners, but we cannoho3n8wgtnjlk ep ;4pe; f4y/2t see around corners; yet both sound and light are waves. Explain the difference.knp lwnefpeg j y;32o/48;th4

If Young’s double-slit experiment were submerged in water, how would the fringe zo1+s yde 5z056erg+c0 s7 m.m3u- nfhjktcrmpattern be chang m6zy j00zsge5-3t ehko cu+fn+md .rs57r1cmed?

Monochromatic red light is incident o zw 0 rl5l94u*uxil 3qw+lqu4sn a double slit, and the interference pattern is viewed on a screen some distance away. Explain how the fringe pattern would change if the re uwiu*0qqs l5r3+u 4xwlll9 4zd light source is replaced by a blue light source.

Two rays of light from the4**kwd )mpgoo+ o7qfj same source destructively interfere if their path lengths differ bdooj o7 m)qfpkg**4+w y how much?

Why was the observation of the double-sl-4 ra0)xpfkfdj7,b/ ew xj ic fy+8p.fit interference pattern more convincing evidence for thebej4 rfp8 f)/ix ,wfpxk 0c7 .afd+jy- wave theory of light than the observation of diffraction?

Compare a double-slit experiment for sound w9dhaeg.v- j77lxrc - baves to that for light waves. Discuss the similaritiesx.crgba77 eh-d9v lj- and differences.

Why doesn’t the light from the two headlights of a distant car1p01pxukv j x*8y+ djn produce an interference n1uxv* y0djpxpk1j8+ pattern?

Suppose white light falls on the two slits orl / jbsble/f0 4iu..l p we0ft2;kh0vf Fig. 24–7, but one slit is covered by a red filter (700 nm) and bleulv;/f4 sw b/h lp0.i0rkf 0 ej.t2the other by a blue filter (450 nm). Describe the pattern on the screen.

When white light passes through a flat piece of 1(f7fz wb;efi nc,tr4 window glass, it is not broken down into colo;41rebff ,nf 7czw( tirs as it is by a prism. Explain.

For both converging and diverging lenses, discuss how the focal lh /o8zr ax4t ul/ ,p8uui(kz4vength for red l/xpuvt4 zl ( uh,r8 /kui4zao8ight differs from that for violet light.

A ray of light is refracted through thrce7)yc7on. xd *sr 9qaee different materials (Fig. 24–55). Rank the materials according cex7sq7cyod)9a .r n*to their index of refraction, least to greatest.

Hold one hand close to sgq ,xet 8tz).your eye and focus on a distant light source through a narrow slit between two finx.tzsqg , t)8egers. (Adjust your fingers to obtain the best pattern.) Describe the pattern that you see.

What happens to the diffraction pattern of a single slit ifid( 4p6x +hqpv the whole apparatus is immersed in (a) water, (b) a vacuum, instead of in air.(x 6vhpqdp 4i+

For diffraction by a single slit, what is the effect of increasing (a) the slbfsa;0m)as ndnc s/ 2z5v-kd:it width, and madcds/vs 5:na-;s bf2z )k0n(b) the wavelength?

What is the difference in the int20oeflfdfx 5sl2t5(nerference 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) closelyh 2 j,ja pprmo3ycw4p07/bs6 y 4j3ysy /j mppparhw6 7 ,20cbospaced slits?

White light strikes (a) a diffraction grating, and (b) a p 42bh .ynd8ucq(mitwya;i 8u 2rism. A rainbow appears(ti y. cau42di ybnmh28u;q8w on a wall just below the direction 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 z f5- h,nkl9imbetween 400 nm and 700 nm, incident normally on a difffm5n9z ,lki-hraction grating, for what orders (if any) would there be overlap in the observed spectrum? Does your answer depend on the slit spacing?

Why are interference fringes noticeable only for a thin film like a soap bubb7 r eme/q 1ie/p-orv;kkh5f0 rle and not rk eev7 q ih/;peor-m105/fkrfor a thick piece of glass, say?

When a compact disk (CD) is held at an angle in white8dfd b kz1pa. e15k9qm light, the reflected light is a full spectrum (Fig. 24–56). Explain. Wh5d9.pea1qmbkf 8 1zd kat would you expect to see if monochromatic light was used?

Why are Newton’s rings (Fig. 24–31) closer togethern9 u,temioyy 6ui.j 8, farther from the center?

Some coated lenses appear greenic+jg. th72 cd k*y-yf1fw1nnbsh yellow when seen by reflected light. What wavelengths do you suppose the coating is designed to transmit co*wk 7bnjf+gth y- ccf 12.d1nympletely?

A drop of oil on a pond appe-ux pey6:iw )iars bright at its edges, where its thickness is much less than the wavy-iw:p ) xeui6elengths of visible light. What can you say about the index of refraction of the oil?

What does polarizatim hus21qy/:t zon tell us about the nature of light?

Explain the advantage of polarized sunglasses over normal t8 6erwh)jwesl w w0a1(inted sunglasses.

How can you tell if a pair of sunglasseslku;i qkw0 ja78yd/3 y is polarizing or not?

Two polarized sheets rotated at an ang ms1ui f)aliir-6; n1tg:vz)jle 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 2b/:fx qd q:q0/tyrdp if the Earth had no atmosphere?

If the Earth’s atmosphere were 50 times denser than it is, would sunlight sa n*sgc lh3h68:we/flz5 ne8wtill be white, or would it be some nf h*gll:w c8e8/ 5eaz6hns3w other color?

  Monochromatic light falling on two slits 0.016 mm apart)qq5dlwok8 5 x r2kxn: produces the fifth-order f:25rd5 8qkk)nxxowq lringe at an 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 angle of e/3u8wthse y*a t5a,d18$^{\circ}\,$ 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 mm apart. Suc gr86:dn nrb.ccessive fringes on a screen 5.00 m away are 6.5 cm apart near the center of the pattern. Determine the wavelength and frequency of the lighcb. n8gnrdr:6t.
$\lambda\;=\;$    $m$
$f$ =    Hz

  A parallel beam of light from a He-Ne laser, with a wavelength 656x7.hiu pp9f )r2cyd lkouqkx6b2 w::: nm, falls on two very narrow slits 0.060 mm apart. How far apart are the fringesr2d9x :pcfky7 u2 lpk.wqh)io:b6u:x in the center of the pattern on a screen 3.6 m away?    cm

  Light of wavelength 680 nm falls on twy xyamsl6d1+ntrfhi b +1(3 8jes52 xad9l+u to slits and produces an interference pattern in which the fourth-order fringe is 38 mm from the central fringe on a screen 2.0 m awam2 1+1etd9xd+ fsbyj3turylnxlis 5( a8+h 6ay. What is the separation of the two slits?    mm

  If 720-nm and 660-nm xy;qis t.w dx6nk(n)gpiwr-52i9l *ilight passes through two slits 0.58 mm apart, how far apart ip9swti dn)xg;( niw6yl 2xi5rq.*-k are the second-order fringes for these two wavelengths on a screen 1.0 m away?    mm

  In a double-slit experiment, it is found that blue light of wavelength 460 nm giz 3+f etl ;w2p6bllf3ives a second-order mabfe6p3lfw+t2;3 l ilzximum 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 ti4gnk18m/j c p ;/tvn os3cwf/hrough two openings 5.0 cm apart in a board. At a point 2.0 m beyondvwgtpc /i j3ko;cm/n8/ 4s1nf 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 placed in front of the lower sldp gjzf-v 4k./r mv;,zit in Fig. 24–7 so that the two waves enter tgrj.;-pvm/kz f 4,zv dhe 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,j*r wlntaj;ycg 6b*i-;4 z 1jl b-;bhy 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 *j4bwjn;j ; 6b;l gi hy-1ryaztb-*clthe central bright spot will the second-order maximum of this light be located?    mm

  Two narrow slits separated by 1.0 mm are ilgx(j07k(idkd( + heaj luminated by 544 nm light. Find the disjd(g (kea0djxh+ 7(ik tance between adjacent bright fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 nm in air falls on td, wqnu1v4n:iwo 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 of a double-slit a3xw g /x.x tt6l1(noeipparatus illuminated by 640-nm light. Txt n6x (g1/i teowl.3xhe center point on the 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)-z g 1v-geh)8 5houc rz8ogw)s exceed that of violet -5wg8sghuvz-) oghcoe 8z)1 rlight (400 nm) in silicate flint glass? (See Fig. 24–14.)    %

  A light beam strikes a piece of glas,/aq p2 iq+m0 cbygx9t2) +i(qqsz pzhs 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 wav2:d1zi jsu. hwelengths, $\lambda_1\;=\;450\;nm$ 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 wided.xpt66pc pn,r . ngw0s hsgj,o ;j)(l, what is the full angular width of the cets nohc6w,p(;lp .r6.gn)x gd, psjj0ntral diffraction peak?    $^{\circ}\,$

  Monochromatic light falls on a slyc h5mj vq3eo* zb15d7it 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 sli+g nwn+m*f x-ay u8o21nocf3 wt 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 illuminatedfby:dbf. --u/iq wn t7 by 450-nm light. What is the width of the centri y/uqfw-b:bd -.nt f7al maximum (in cm) in the diffraction pattern on a screen 5.0 m away?    cm

  Monochromatic light of waz+x6m:4e 2rjunfk6c y velength 653 nm falls on a slit. If the angle between the first bright fringes on either side of tf+ kx2jzmny e4: uc66rhe central maximum is 32$^{\circ}\,$, estimate the slit width.    $\mu m$

  How wide is the central diffraction peak on a screen 2.30 m behinde1 9)mrinu5jl8 ew-hf a 0.0348-mm-wide9)w fie-jr1m85u hln e slit illuminated by 589-nm light?    cm

  When blue light of wavelength 440 nm falls on a single slit, thef:8;a z( vxojr first dark bands on either side of rf8x zva; o:j(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 creates afw cjdum;/ f)* central diffraction peak that f c)f;*/mwdujis 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 diffraction maximum is 4)bl))l/de;b 6k md4yyy75ljo cor1o h.0 cm wide on a screen 1.50 m away, what will be the width of the diffraction maximum for light of wavelength 4moeol4 ) k1ly) ; crddy6b) 5jhy7/lbo20 nm?    cm

For a given wavelengta3xnya5j4xc* h $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm lighty;ghqw0gn8e p5yelgrj j b2z1.k ;+0;c/hreg produce a second-order maximum when falling on a grating whoebpyjq8gew;k c00 1;.ger 5r/l2gjyg hnh+; zse 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 thegfe le8tvu70s, ue, /p third-order occurs at an 18.e upuvt,s/f7e0 8l eg,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 fa vrqph6y-b4c*wlb99 a lling on a diffraction grating is observed-y p6 *9a4wbv9qrchl b 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 h-p h ff,aiop:0as $ 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 acg1)dhhavo:9*fgp2 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 speu.ft xci *u5bms(-wg9 ewy a+-ctral order that can be seen if a grating with 6000 lines per cm is illuminated with 633-nm gww5s 9t--b( c*me .+aiu xfuylaser light? Assume normal incidence.   

  Two (and only two) full spectral orders can be seen on either side of 0shw.uzn a) s1/n+ ubhdr+r,sthe central maximum when white light is sent through a diffraction grating. Wh dazhb1 hnuws+/0 s.)ru,s+ nrat is the maximum number of lines per cm for the grating?    $ \times10^{ 3}\;lines/cm$

  White light containing wavelengths from 410 nm to 5be2qtef4 50x jjv+hd750 nm falls on a grating with 20jqt+x4 dhbfeej5v 5 $8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which produces monochromatic light of4dzh: 6z*nlnu;a-(-ihmkgyv.ecp 9 w 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 li mrroi(r +wjp *:lz0j(nes 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 w phn7f2em k*i9avelength is most strongly reflected at the center of the opn2 fim h*e7k9uter surface 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 24iny:n bet;w (rbu/ 965ggvk5k–8 if the glass plates are each 26.5 cm lrv:kyeg t(6; iu/b9wkg5nb n5ong?    cm

  What is the smallestoizi- ,h0: )g mavv)pz thickness of a soap 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 ya6ee8)ka 5 fz; gpg+bnellow ($\lambda\;=\;570\;mm$ 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 counj (khug(7o-rg4 ,x zvhx0u)ynting 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. 24–31). How much thicker is the center th 0hgzx)ny(xkgh (7rj- ouv4,uan the edges?    $\mu m$

  A fine metal foil separates-c pz.e *hj6-vdx l,+cn4yvem one end of two pieces of 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+ d*hv4x - vnczje-pc.e,m l6y is the foil?    $\mu m$

  How thick (minimum) should the air layer be bejr .sl0(m3udzbnv02lq+ln7b ks-3s q tween two flat glass surfaces if the gla+ .jqklsn3 n lsbus z07-qv2 r3m0(bdlss 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, suspected of being a stolen diamondi+1 jg)d*u . kmiin+ahsxb;/71oyw av $(n=2.42)$ 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 y4+y. e(iih*j xrkt9b $(n=1.36)$ 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 apparat q whrflr5a-30us (Fig. 24–31) is immersed in a liquid, the diameter of the eighth dark rin 3awlfrrh 5-0qg decreases from 2.92 cm to 2.48 cm. What is the refractive index of the liquid?   

  What is the wavelength of q pq1p /iq7g:cb+hf egmq0kp ,/z -+cwthe light entering an interferometer if 644 bright fringes a7 e-qpkqb+1/c whq/,i:p0g q z pcgfm+re counted when the movable mirror moves 0.225 mm?    nm

  A micrometer is connected to the movable oe.b /t5s(wqkmirror 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(se. tw o5bk/qkness of the foil? The wavelength of light used is 589 nm.    $\mu m$

  How far must the mirror d6veel ltb8e *m/q ,/h$M_1$ 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 te*h kyq6)e;x jhrough 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 intek*6e;jqh xey) rferometer is in vacuum. $n_{gas}$

  

  Two polarizers are orientf:kk/,o nej4e ed 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–glp 8 kjq+ -;vtfp*/gmxh8.0 ikmd)unw gass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerged in water if the light is 3 mt,r qyp b7a ap7:g+kus /tdh1bzp+3hitting the di :k btdh+m7pq3rp+g ty/ ba,pas3z7u1amond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the lighwut;huf6 b8b; t passing through them is a maximum. At what angle should one of them be placed so that the intensity is subsequently redbf; t8buu;6 whuced by half?    $^{\circ}\,$

  At what angle should the axes of two Pola+x 4p6kjc1 j1 vprltt-roids be placed so as to reduce the intensity of the incident unpolarized lighj x v1kp+ -r6tcplt41jt to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oriented at -r3zo2 oo8p kws2 x 0ecw.ng5n40$^{\circ}\,$ 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 orientruho x2-jr0el- .8da jed 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’xk383f td v5)zvty t+xs angle be for reflections off the surface of water for light coming from beneath the surface? Compare to the angle for total internal reflection, and to Brewster’s angv5 txk z3 t3xt+8fyd)vle 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 0m( ohg2psl)6 *sgdfrPolaroid sheets, each of whose axis maf(p0grgs )dm 6osh2 l*kes a 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength *c7 mt /tjpsz;qw20-4bmsaz r$ 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 fr y ;w5bism,+suom mountains or airplanes can interfere with the direct signal ,siumb+w;y s5from 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 th( lttgctvz5h( c5v48m.h1 anvrough a diffraction grating with v15a tv4h(thvl n5 c.g8c(tmz$ 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 through two narrow slits;q)dj 8 vee 8wi,-bvhv 0.60 mm apart. The screen is 1.70 m away. A second source of unknown wavelength produces itsdv,)v w;bevjeh8 q8-i 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 operatings x)9p,tpsr8j at 102.1 MHz broadcasts from two identical antennae at the same elevation but separated by an 8.0-m horizontal distance d, Fig. 24–60. A maximum signal is found) jt,psxrps98 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 doorway 0.88 m wqocd0shdq f1) *;uat +ide, and blows a whistle of frequency 750 Hz. Ignoring reflections, estimate at wd1so c)htudq*a+f 0;qhat 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 w6g f54,qcbv8 58 q 4fzabnq7qu/*hbg epdsd-uidth D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a series of parallel linumk+;v 3e2 )cdlye 6waes across them. When normally + cmu2al)yde k 6;ve3wincident 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 grath3y.e:hansp eiq:spudk 9 + k+*g-i8zing have if there is to be no second-order spectrum for any visible wavelen-+e senhpq +si*u:z.ki9: hy 8d3kgapgth?   $ lines/cm$

Show that the second- and third-order spectra ydm j7 8oon-y/z;m qn4of white light produced by a diffraction grating always overlap. What wavelymnd oqy4 m;noj7/-8 zengths overlap exactly?

  When yellow sodium light,8 iurnjme6 ..rax subao2)9idy0k b( + $\lambda\;=\;$ 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 ande/ 2: m;xeevqm 5s5dug the pattern is viewed on a screen 2.5 m from the grating. The incident light beam consistsm:gmev5 5d ;/ueq 2sxe 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 aj;zssxb/dm (0vl4qp5 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 cho4 sv(mlx0 z;jbq s/dp5ice for an answer?

  Monochromatic light of variable wavelength is incident normally on a thi:3 tpt;bb ic +q+qgq/cn sheet of plastic film in air. The reflected light is a minimb3;pqb :qqct++g/i tcum 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-reflecti(z-e31tqricg :bbeb 8ve 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 (;1r92inbti-mt bv/ pinon-zero) thickness for the air layer between two flat glass surfaces if the glass is to appear dark when 640-nm lightnipi-t vmrb/1t; ib9 2 is incident normally?    nm
What if the glass is to appear bright?    nm

Suppose you viewed the u:vng bfs+x/1light 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. Discussu v+fg/n bxs1: the relative size of the minima compared to the maxima and to zero.
24-30
24-36

  At what angle above the :u - 9j apmdz6ms 3y+49rxlfpphorizon is the Sun when light reflecting off a smooth lake is pdrp4 3lu:p xzf9a-9smp+ ymj6olarized most strongly?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so551gs6us w wi/q-mrnz 8 co/oo as to reduce the intensity of the5mzwg 6w/snooo-5u/ 18qci s r 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 whose transmission axes aruwg0c.e tf3q/ e at right angles. A third polari0c/uw3f gq.etzer 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 success;i o1hism71yzoqjv 2*b-l+yqion 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 a p7cnmkpss7 zj *:; rm5gc29hst the Moon, which is approximately 380,000 km from the Earth. Assume the laser emits wav7 25; jhcms *:kspm7pgzr9nsces 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 polarizer9zm4r wlwqj;tp ns xi1.. m-i8s are each 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 )i(ziq)w/ h gc 1mk;fh$(n=1.34)$ 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 antennab hg)uqp 2d2lb3 riitaq9*o xcl o*6-.s radiating 6.0-MHz radio waves in phase with each other. They are located ct qoiuq*rd- xbo2*gh bpl23l )9.6ia 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 twogean1 fs,n+*t wavelengths, 420 nm and 650 nm, enters a silica*a1 ,fnne+sgt te flint glass 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 lenefikh9b. 2/rts has one flat surface and 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