Does Huygens’ principle apply to sound waves? To water waves? amqyg ga2 ,r0)Explain.

What is the evidence2j)qnuoqdx .p sa3.2t that light is energy?

Why is light sometimes described as rays and sometimes as wa3f8q-fkkh+afm*8 jfq ves?

We can hear sounds aroun/i+7b* zffaxs d corners, but we cannot see around corners; yet both sound and light are wavesfxf+/ sa*iz 7b. Explain the difference.

If Young’s double-slit expehhnd9fa5z0q:tgk) m8 riment were submerged in water, how would the fringe pagh )tz:05 f9qkn8hdmattern be changed?

Monochromatic red light is incident on a double slio3 4 q:v6bt(bp *g h6fiaxme1m.ib)rst, and the interference patterf6m a:tq)(b 6io14vghsxmr 3ebp * bi.n is 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 the5bcp 5c;ij5 n67 0qt.hspdnzeir path lengths differ by how much?cc6 b;pzhdp n075st55niqj. e

Why was the observation of the double-slit interference pattern more conviw-ee j nf59;aoncing evidence for the wavee9wa-5 nofj; e theory of light than the observation of diffraction?

Compare a double-slit experiment fqcq91e* 0s hchv)v6 oior sound waves to that for light waves. Discuss the similarities and differencesscv96oc)q 1iqhvh0e *.

Why doesn’t the light from the two *meehms) do*y u2,0uou- hum3headlights of a distant car produce an interference pattern ymu,e s)de h*hmmu*o u32ou0-?

Suppose white light falls on the two slits of Fig. 24–7, but one n bc 2+hy2qw3e9yg9vh slit is covered by a red filter (700 nm) and the other by a blue filter (450 923+begv cyn9h2 ywhqnm). Describe the pattern on the screen.

When white light passes thropy iu+;b1fc;zxkt32p6xilk s u2ql0 6ugh a flat piece of window glass, it is not broken down into 6ts2k6lixi;yfx ;2 bu1u3+q0 z clpkpcolors as it is by a prism. Explain.

For both converging and diverging lenses, discuss how thsfc/f8w +p j*5u 1lyhy3snm m5e focal length for red lightsjy+ 85m/fs * un1pcyh35lw mf differs from that for violet light.

A ray of light is refracted through three different materials (Fac./9lce s2mb0edj l(d bpt gn*o)7r(ig. 24–55). Rank the materials according to their index of refraction, least)*7 /ebotbjne(cg l20l9(.sc ardpm d to greatest.

Hold one hand close to your eye and focus on a distant light source th;zxq5 fyc m),prough a narrow slit between two fingers. (Adjust your fingers to obtain the best pattern.),fm; p5yzcq )x Describe the pattern that you see.

What happens to the diffraction pattern of a single slit if the whole appfzl/vb:z w.1 8tlcxu3l.aee* aratus is immersed in (a) water, (b) a vacuum, instead of inazl vxl twzlee13/:b.cu 8*.f air.

For diffraction by a single slit, what is the effect of incrik l*.n;ljo+c easing (a) the slit width, and (;klc.j+i no* lb) the wavelength?

What is the difference in the interference patterns formed (a) by tw:a v yzpjiw0dys6.nq2).cg.e o 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, *ue8h27 cpoay229eh vnf -dh n(b) closely spaced snuh yapf7cv e2ho d8- nh*e229lits?

White light strikes (a) a diffraction grating, and (b) a prism. A rairc ,epmerl6 n)o2) ev(yu+ v:;hbpc+k nbow appears on a wall just below the direction of the horizontal incident beam in each case. What is the color of the top of th+ep;(:vky,ol2r)) n ceuv chbp+mr6ee rainbow in each case? Explain.

For light consisting of wavelen,eg0tvzd6k; y0( mm ojgths between 400 nm and 700 nm, incident normally on a diffraction grating, for what orders (if any) would there be overlap in the observe0 emk,;6( yvz tm0dogjd spectrum? Does your answer depend on the slit spacing?

Why are interference fringes noticeable only for a thin film like a skj .vt )g rs444mmy,p ml,e+sxoap bubble and not for a thick piece of glass, 4em s, xslr+mg44mp kv.yjt),say?

When a compact disk (CD) is held atogrvt)m8 +e 6/6ctwj c an angle in white light, the reflected light is wgm ctt 8oer6)j/c+6va full spectrum (Fig. 24–56). Explain. What would you expect to see if monochromatic light was used?

Why are Newton’s rings (Fig. 24–31) closer together farther from the cente yy/ixy5 glk;(zkvg,qo2 /+)efadbv.r?

Some coated lenses appear greenish7,m++txj+3j wlr* jcbuc oj8r yellow when seen by reflected light. What wavcj+3r,lw jxju8+rcm7*+t jboelengths do you suppose the coating is designed to transmit completely?

A drop of oil on a pond appears bright at its edges, where its thickneseq6b7r:rdm -1 nl ,lnas is much less than the wavelengths of7lq ln ar1d m6-,:renb visible light. What can you say about the index of refraction of the oil?

What does polarization tell us about the natur)yzea9hzd nwi8n/9/ v e of light?

Explain the advantage of polarized sunglasses overckga:v fo:q.+20f+: tt lvo gng*erw0 normal tinted sunglasses.

How can you tell if a pair of sunglasses is py 5t1hm:ap pr:j9i8eu olarizing or not?

Two polarized sheets4sc:aj 1o.nfx 9xk 29pl2wzo q rotated 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 color of the sky if the Earth wujsgw jyoh:t:z;4+n(-mf g2had no atmosphere?

If the Earth’s atmosphere were 50 times denser than it is, would sunlight stilj+has -ls 4)xwl be white, or would it be some other color?)l-+ hj4w ssax

  Monochromatic light falling on two slits 06f - )r+y3mamg1wmtlk .016 mm apart produces the fifth-order r falg 3tm+k)1-6mywmfringe at an 8.8$^{\circ}\,$ angle. What is the wavelength of the light used?    $ \times10^{-7 }\;m$

  The third-order fringe of 610 nm lightmh4w:wu5n . cr 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 0.048 m *;q 8d3f*unurbf .* .spqgijrh3(x fru)n f6zm apart. Successive fringes on a screen 5.00 m away are 6.5 cm apart nep*x b(.udr ur.6*qni g*ffzns u8;)qhjf33rfar the center of the pattern. Determine the wavelength and frequency of the light.
$\lambda\;=\;$    $m$
$f$ =    Hz

  A parallel beam of light from a He-Ne laser, with a wavelength 656 nm, fv/e8 * qv4dzedalls on two very narrow slits 0.060 mm apart. How far apae zdqvd/*4 ve8rt are the fringes in the center of the pattern on a screen 3.6 m away?    cm

  Light of wavelength 680 nm falls on t9rd9 3gdk4e+ci 1d(mxhwj b uly kun1/++; jrjwo slits and produces an interference pattern in which the fourth-order fringe is 38 mm from the central fringe on a sk1ilkydm e du94b+;c+(rwnjuj1/hd3r+ gjx 9 creen 2.0 m away. What is the separation of the two slits?    mm

  If 720-nm and 660-nm light passes through twz16yn wtpzf nb(38t j4o slits 0.58 mm apart, how far apart are the second-order fringes for these two wavelengtnyb(813twzp jn64 ftz hs on a screen 1.0 m away?    mm

  In a double-slit experiment, it is found that blue light of v :(he4r efdcd- e)h7bive;yp hwr*)5wavelength 460 nm gives a second-order maximum at a certain location on the screen. What wavelength of visible light would have a minimum at the saeb4h:) eh e5 fvvhr (;)yr-7p *wdidceme location?    nm

Water waves having parallel crests 2.5 cm apart pass through two openinglg* scx a dl-1:;item.+ujc9+nuq g 75)kecdrs 5.0 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 little or no wave actig)c dd1 e-au;rc:s5 + ql *tulcjn.xg+emi9k7on?

Suppose a thin piece of glass is placed in front of 6t-wh3w8 kj4muyz( aj the lower slit in Fig. 24–7 so that the two waves ente-kw 6jhz may8j (wtu43r 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 experib,2emhvdo*-rfcvjuby5pezdl/ 41 *1 ment, 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. Ligvbdh,e4v-uz*2m c r 1e1f jp5l b*/odyht 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 1.0 mm are i.fg(bhu-*;ucf g yc3 hu hyf,5xiv:,blluminated by 544 nm light. Find the distance between adjacent bright frifbhy*u.xv hhgfugy i bu-;:,cf 5c,3(nges on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 nm in air fadzv(;ivkq1fh 3h vhc3(/a4palls 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 ofcg89q v3ue(r t a double-slit apparatus illuminated by 640-nm light. The center point on the quvtg3e r8c9 (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) exob+ kwp4l.r5 r8ev/ktceed that of violet light (400 nm) i kk5.t/ owr +4vlpeb8rn silicate flint glass? (See Fig. 24–14.)    %

  A light beam strikes a pi ndx0:s i9s mjbq)vl0-ece of glass 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 t 0u+os/*ee/roqnvfdwbx i9+- wo 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, what is the f,da4.vgf bvjb;3iz mw9x6p/d ull angular width of6 jxpb/;gf bz d3am4,w 9i.vdv the central diffraction peak?    $^{\circ}\,$

  Monochromatic light falls onacb qm(sh a322 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 ony,dtl+ znoetw; p*.,n 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 is illuminated by 450-nm light. + 4d/bum2olct What is the width of the central maximum (in cm) in the / 2b+ltu4odc mdiffraction pattern on a screen 5.0 m away?    cm

  Monochromatic light of wavelength 653 nm falls on a slit. Ifuj fp:/ ) 7rfw*nriigg-h:3jja 6)rxy the angle between the first bright fringes *giwjjunj fg:xihar: 3r/-)7p) ryf6 on either 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 mpd lw03fzf3z5 behind a 0.0348-mm-wide slit illuminated by 589-nm lighff53pzw0 zdl 3t?    cm

  When blue light of wavelength 440 nm falls on a single s2vrfy5t11p0x o 1ebfrlit, the first dark bands on either side of ce5vf12 e01bfpyx1rtronter are separated by 55.0$^{\circ}\,$. Determine the width of the slit.    $ \times10^{-7 }\;m$

  When violet light of wavelew36jtg 9of, uength 415 nm falls on a single slit, it creates a central diffraction peak that is 9.20 cm widegeuj wtof6,3 9 on a screen that is 2.55 m away. How wide is the slit?    mm

  If a slit diffracts 65f 6 3oj8in gh7os.xl5tyiu9y/0-nm light so that the diffraction maximum is 4.0 cm wide on a scr65oul9o .i7ity8 jxs3f nhyg/een 1.50 m away, what will be the width of the diffraction maximum for light of wavelength 420 nm?    cm

For a given wavelength: *nj5 f8p x)vmfi 0+vxrkz.aw:vl(km $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm light proda, m 2ciep*zd7uce a second-order maximum when falling on a grating whose sl*,e2 z7 dimapcits 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 ns9gl4l6fh -yn2i6 sfgrating have if the third-order occurs at an 18.0f siln64yn 6sg2- l9hf$^{\circ}\,$ 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-gsg+5 ou ;ci(z jav4: ,qrbel8-*cm fenm light falling on a diffraction grating is observed at -,4:fi5 8 gq *ls cvcauzogbr;+j( eema 15.5$^{\circ}\,$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction grating ipud c780a c8 3zgujg4c r4pc28ojao ()p5zcq 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 lbv* ezr 7ynv 2r6b(0.rtb23s bsjaw1a $9700-line/cm$ 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 grating with 6000sz3 ymiq5j d48*ecy- d lines 8md35j z4 -dy*iesqcy per cm is illuminated with 633-nm laser light? Assume normal incidence.   

  Two (and only two) full spectral orde9q e; yh.uf0o3opi:mors can be seen on either side of the central maximum when white light is sent through a diffraction grating. What is the maximum number of lines per c9o e 03:iopu.oqhyfm;m for the grating?    $ \times10^{ 3}\;lines/cm$

  White light containing cs5,g tq;0tcv- 47fc+c pkc yawavelengths from 410 nm to 750 nm falls on a grating withfc0-c7cv ;gt4k ,5c ta+spcq y $8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which produces monochromatic ligh+pm6o:j* ua gw+vk1q9 iobna+t 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 lines are measured bu kexa1z p.z1t1 o) u*:(zxhzcy 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 wavelu vfw*bhp 0avi k2/8(kength is most strongly reflected at the center of the outer surface when illuminated normally by whi8vk2u /b0pw*(vfi kh ate light? Assume that $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringiaj o8o uvf,-8es in Example 24–8 if the glass plates are each 26.5 cm voujof -ai8,8 long?    cm

  What is the smallest thickness of af:*upls9a+ lw 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 t,dm. h kj .sp0ewr6-myellow ($\lambda\;=\;570\;mm$ 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 riryhv0hj667 wt(prp ;i te gf 7i 0l(*h;rgz9dmngs (not 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. 24–31). How much thicker is the y ghri(;pr076*twh9m( idleft; pz rg6jv0 7 hcenter than the edges?    $\mu m$

  A fine metal foil separates one end of two pieces of optically flat glw6q6e(. 8/1gu mtv zbc)nbqnaass, as in Fig. 24–33. When light of wa6 qe (wzc8 n61/uamtv)bq.ngbvelength 670 nm is incident normally, 28 dark lines are observed (with one at each end). How thick is the foil?    $\mu m$

  How thick (minimum) should the air layer be betweep v4destlizw2- i955jdhj/ z9n two flat glass surfaces if the glass is to appear bright whs-j9hp2tie5lzi4z5dw v d /j 9en 450-nm light is incident normally?    nm
What if the glass is to appear dark?    nm

  vA piece of material, suspected of bqfqhps1f n 1u i3t;a56cmi.k 8eing 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 alcohol g )z9f326 qjpp81a rylyx ibe)$(n=1.36)$ 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, the d wv lmb:vt/,(diameter of the eighth dark ring decreases from 2.92 cm to 2.48 cm. What is(mv /dlw bv,t: the refractive index of the liquid?   

  What is the wavelength of the light entering an interferometer if 644 d;4t .zj up nh3v7v dhk *rrs1,u,,jesbright frinr,pjjkuz rh, 17 d h;.td sn4ue3*,svvges are counted when the movable mirror moves 0.225 mm?    nm

  A micrometer is connected to the movablp. h (/u;ay 1.cca8ahoh kojinrlt(( +e mirror of an interferometer. When the micrometer is tightened down on a thin metal foil, the net 1;a( h+ ooj ia.n kh8yrtac(.(lhcp/unumber 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 mirrokj2bx za/9of 9r $M_1$ 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 through a smaln l3n-8,d1 /km0z;wftg j thudp-wr6il 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 d/ wkn,u8il tgpjdmrzt3 ;1hf 6w0 n--the gas, assuming that the interferometer is in vacuum. $n_{gas}$

  

  Two polarizers are oriented at 1t.gsi*yjr8o:1 fzbl c yx b,465$^{\circ}\,$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s angle wi a 0h.*fobf)/ysin.for an air–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerged in water if the light is hittingz ) p1rl6n7 a x15c8qgztm3dbg the nagcgz1dl m1z5 b 3)qr 768xtpdiamond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the lig u+y+vj)b,3cnulmuuam 1eyzx89 ah m;nav4.-ht passing through them is a maximum. At what va l ju+yymv; )9,1un3xz+aane.4cu8 m hu-bmangle 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 placed so as a66gncw *5s 9r: kp:gprj4 :.a7y(bt dn fbcgjto reduce the integp b4cdr ja7n9:6ptrg j5k(f:g a:cwb6sy*n.nsity of the incident unpolarized light to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are orieio.u;qys)g : izzbj;8nted 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 atqpktkcnl b4yq 08h531zzcr e mm(--:w 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 off the surface s9; y:qv7.q dcr6xl(vbql,ngr6 / jigof water for light comig9llbxr vqq6 7,r./vyg ndi (:;s6cqj ng from beneath the surface? Compare to the angle for total 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 passe0z 1)k:mwz7 jp/8ypivq(ro np s through five successive Polaroid sheets, each of whose axis makes aq7zp)(1v0m: 8z ynj/ip o wkpr 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength wk(fq)rrx)e/ 5l hvm8$ 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 can 2dbtuya0p)+t interfere with the20)dy t+abtpu direct 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 diff:q unz00 krnd4-0)sm s ze7kmbraction grating with sne k7mru )nq0:dsbk4zz0-m 0 $ 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 pass zb6 ud.g9ej0hes through two narrow slits 0.60 mm apart. The screen is 1.70 m away. A second source of unknown wavelengdj0he9 zbgu6. th produces 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 ab6zdoyn,l, -it 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 along the midline, perpendicular to d at its midpoint and extending yolni z,d6-b ,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 wide, jd2v 2rvwq ng/6 0wle0and blows a whistle of frequency 750 Hz. Ignoring reflections, 2dn2w/g06 ev 0 rjlwvqestimate 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 g*wo8 glhay53width D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a series o a;0oc;kpdo0x f parallel lines across them. When normally incident 460-nm light pc;0o0 kod;axis 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 no second s2eiw,ye6/k t7fl z9z-orf/k z9t ze,slwe672 yider spectrum for any visible wavelength?   $ lines/cm$

Show that the second- and third-order spectra of white light produced by a diffr*c 9+n5b)2knewlaa (rzhz shx 0xfn(3action grating always overlap. What wavelengths ovzsn0a(hzw cka2 *h xn xr)l5feb9+3n (erlap exactly?

  When yellow sodium ligcx a 94mlnp67qht, $\lambda\;=\;$ 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 zfr,, d/fyzier5v a-y- ho+y9pattern is viewed on a screen 2.5 m from the grating. The incident light beam consists of two wavel f,ayfr,o+ h9di-e vrz/y 5yz-engths, $\lambda_1\;=\; 4.6\times10^{ -7}\;m$ 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 150 nm thickfa-5c /phk4kmness of it, when laid on glass, is needed to reduce reflection to nearly zero when light of 600 nm is incident normal-4 /mhac5k fpkly upon it? Do you have a choice for an answer?

  Monochromatic light of variable wavelengr pnu u018hpk5th is incident normally on a thin sheet of plastic film in air 0up8nkrp51hu . 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 thickness needed for an anti-rd mc4+./y; usv p6mg0jlue/sceflective 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 between two flat glasuwo3+( 8c/txwxwjiy ;qyx46i s surfaces if the gl xy3 jcxoqywtww;u6(i4+x8/iass 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 transm:id.;nlp m: mbht6z8 bitted 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 valmbh8p:.6t idzn:m ;b lues of index of refraction. Discuss the relative size of the minima compared to the maxima and to zero.
24-30
24-36

  At what angle above the horizon is the Sun whekpgajq*f2rr8j+ qx .+ n light reflecting off a smooth lake is ++ * pa8.rgr x2kjqjqfpolarized most strongly?    $^{\circ}\,$

  At what angle should the axes of tw5q nsj00u,n yro Polaroids be placed so as to reduce the intensity of the incident unpolarized light by an additional factor (after the firnj yq,usn 005rst 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 are 5ltqhi ,s il e,g0is/2at right angles. A third polarizer is placed between the first twolhi ess/ i2ilt0g,5, q 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 succession with their axes vertical, atx9x l+ qv6m7lpdq *i;n 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 Moon, wh oea3;* 31gcitdewg-hich is approximately 380,000 km from the Earth. Assume the laser emits waves oe-g *ti13ow3ag d;c ehf 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 6 ;kw0ec6/uoxc e i -4kpbbc* c1.jmmx10$^{\circ}\,$ 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 a119yehz h;m/ynr +fa$(n=1.34)$ 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 w;o.yi77vo/z 6ymvpqpm s) 6fl aves in phase with each other. They are located at poi oy6/pvlpq7) v6 sf.7 ;omzymints $S_1$ 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 c uf 7bbuc1ox2wijh*.5 oy ie-9ontaining two wavelengths, 420 nm and 650 nm, enters a silicate flint glass equilateral prism (Fig. 24–58). 7oc5i u1fj9 i2eyobw*b -x hu.
(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 and one r:no6 *o6bc:a.mr))twfbf a t 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