Does Huygens’ principle apply to e728;xs hm1 wafntj;koja *mi6vg,c 5 sound waves? To water waves? Explain.

What is the evidence thil4l2 yx3 xfj6yxy ;3hat light is energy?

Why is light sometimes described co:(9v h hb;gad7wt+yas rays and sometimes as waves?

We can hear sounds around corners, but w++ 2 e*ju cmuu,vgfu3re cannot see around corners; yet both sound and light are waves. Explain the differen+v,jguuc3em2f ur +u *ce.

If Young’s double-slit experip*g,1 l fnn9 evoh./+(grle ylrj1l3o ment were submerged in water, how would the fringe pattern be changedpe , 119ro3foy/. glvn(l+*herlnjgl ?

Monochromatic red light is incident on a double slit, ab*h1vf ;f (yww9ut*yfnd the interference pattern is viewed on a screen some disfyy1h fuf;*wtw9(* bvtance 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 patkl;p93a k :qunh lengths differ by p;nqk3l9 :a kuhow much?

Why was the observation of the d9ifakkf3jy d5o c31k *ouble-slit interference pattern more convincing evidence for the wave theory of light than the observation 3a9 k3*15fdky oifkj cof diffraction?

Compare a double-slit experiment for sound waves to that for light waves. Discft*8e7g up9z) *yw sklamq22 dt-.xdmuss the similari2d*79. -)aex us zmmwkdtyl 2qt*fp8gties and differences.

Why doesn’t the light from the two headlights of a d8i rl9mxq/2fv+vyb0j9olp ; distant car produce an interferen8l+rfjv 0;dqmlv y px 2i9b9/oce pattern?

Suppose white light fallcdfo q0w3n 9t(w2uk33sr oduzg9ox.mx o:2q/s on the two slits of Fig. 24–7, but one slit is covered by a red filter (700 nm) and the other by aumd2w/3o9.cdqxtk3zq s9 or3o:(x ou2w0fgn blue filter (450 nm). Describe the pattern on the screen.

When white light passes through a flat piece of window glass, it is not brokeyn)v )e qwbqqx3 3)rc,n down into colors as it is by a prism. Explawv,) qc3q q) n)xbre3yin.

For both converging and diverging cgh g1jlu hdc2b7*ebiokx (7y*lf*; 4lenses, discuss how the focal length for red light differs from that * bcd*2x*eu1h hjc;g 7lklo(4iy gf7bfor violet light.

A ray of light is refracted through three diyt+ w)aqknt-q,.jcf( h+6 hp sfferent materials (Fig. 24–55). Rank the mat+fk(j q y-p,tqs)hw+cht6.a nerials according to their index of refraction, least to greatest.

Hold one hand close to your eye and focus on a distant l /jrmi. c +uw40-jpxcmwl*xz3k8 x 9gqight source through a narrow slit b-.iw9cru z4gc+ w8xx/0kx p qjl3mm*jetween 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 slit if the whole apparatu ifrctiqn9bz6a2z6,/s is immersed in (a) water, (b) a vacuum, instead of in a,ai/bf z ti6n2 cr6qz9ir.

For diffraction by a single slit, what is thepxo+( t kfgwpp7 u9a7;:.bsfc w;7ahh effect of increasing (a) the slit width, and (;pf7g: kcup .wo9hxtspb; 77+ahfa w (b) the wavelength?

What is the differen cne12msaz. 3 t-f 0ewqgrgpl o2w7*6yce 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 advantt tujl+ 9qqj9o9*d ,yra45i mmage of (a) many slits, (b) closely sd9+,9 jjiu rtymmoql4ta*q59paced slits?

White light strikes (a) awbn5r ,oz3 if7 ivrp*;3qw.qm diffraction grating, and (b) a prism. A rainbow appears on a wall just below the direction of the horizontalp. 7 *ib3iv3zof5rm,qrw;q wn 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, incident normallur 3,( k3ei b*eopf wymp6s59ny on a diffraction grating, for what orders (if any) would there be overkifp oermy* (p5336,b9wun selap in the observed spectrum? Does your answer depend on the slit spacing?

Why are interference fringes noticeable only for a thin film like a sou -bawz8pla;xlsh ;.+ap bubble and not for a thick piece of glass, say.aa;-bx;pu s8h llwz+?

When a compact disk (CD) is held at an angle in whit1n/;mi 4kaypw e light, the reflected light is a fuwn/41;ypk ami ll spectrum (Fig. 24–56). Explain. What would you expect to see if monochromatic light was used?

Why are Newton’s rings (Fig. 24–31) closuwu9v :6vojp dm 8:d1 deul++mer together farther from the center?

Some coated lenses appear greenish yellow when seen . tc+y/nup3 ws9 (il lrri63ufby reflected light. What wavelengths do you suppose the coating is designed to transmit s(r ri3ti /uuc w6nfy+.lp93lcompletely?

A drop of oil on a pond appearwlp sz ;z uzow:un(/q 2*8fea:s bright at its edges, where its thickness is much lszezu8plno; u:(2fw/z qw* :aess than the wavelengths of visible light. What can you say about the index of refraction of the oil?

What does polarization tell us about bs+d3 qwi1pp/c4g:fzni nrz+ssw+01the nature of light?

Explain the advantage of polarized sunglasses +3 ;la4twcu ngover normal tinted sunglasses.

How can you tell if a pair of 6f)x8(yythzh sunglasses is polarizing or not?

Two polarized sheets rotated at an angle of fsw;+6m e/wzr90$^{\circ}\,$ 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 color7i7s+ezg(i;9ughcx c rl)jf 8u u+mw3 of the sky if the Earth had no atmosphere?

If the Earth’s atmosphere were 50 times denser tpz(cv(6b+htmm r- ;e hhan it is, would sunlight still be white, or wmr+;(zhe h6bp- tcv (mould it be some other color?

  Monochromatic light fal qkw-7ldy 16pjik5z)uz-i1m s ling on two slits 0.016 mm apart produces the fifth-order fringe at a6pi71 -dzsz k1kuimq w)j l-5yn 8.8$^{\circ}\,$ angle. What is the wavelength of the light used?    $ \times10^{-7 }\;m$

  The third-order fringe of 610 nm light is ob+p s4.c2rvomvserved 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 :kp4 (tfdhdq*mm apart. Successive fringes on a screen 5.00 m away are*khtf(d: pqd 4 6.5 cm apart near the center of the pattern. Determine the wavelength and frequency of the light.
$\lambda\;=\;$    $m$
$f$ =    Hz

  A parallel beam of light from a He-Ne laser, with a wavelength 656 nm, falls on rv:s+bb zx*9tax:fr: two very narrow slits 0.060 r:+:a t* :bfzs9xxvbr mm apart. 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 an interference patty3fe+uk :)lhh ern in which the fourth-order fringe is 38 mm from the central fringe on a screen 2.0 m awayeuyh+ :f) 3klh. What is the separation of the two slits?    mm

  If 720-nm and 660-nm lz7vv22h pr 7hsight passes through two slits 0.58 mm apart, how far apart are the second-order fringes forv7s7hhpv z 2r2 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- pf)w 1o*crf nml+lc) nm gives a second-order maximum at a certain location on the screen. What wavelength of visible light would have a minimum at th)m )*1+ rflfn-cpclowe same location?    nm

Water waves having parallel c wyak/l5j8tv4 rests 2.5 cm apart pass through two openings 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 thltway8v5 k j/4ere be little or no wave action?

Suppose a thin piece of glass is placed in front of the lower sltb tv77 4:brb3sc* oikit in Fig. 24–7 so that the two wab3: 4irt77tvcbsk *o bves enter the slits 180$^{\circ}\,$ out of phase (Fig. 24–57). Describe in detail the interference pattern on the screen.
24-7
24-57

  In a double-slit experiment, the third-order maximum for light of wavelength 50ogta+ gb n+(xmt0ys:lfh8-m*0 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 slotnylf a 8 b(+m+*mh-st:gg x0its. 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 illuminated by 54gau 2tvjdy9.*vpxt ;+ 4 nm light. Find the distance between adjacent bright fringes on a screen 5.0 m from thepg v v dx2jyt*;9t.au+ slits.    mm

  Light of wavelength 480 nm in air falls t aiglt c,ha/3l5 06kyon 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.*/giusnpv-g)t )wbl( 60) covers one slit of a double-slit apparatus illuminated by 640-nm light. The center point on the screen, instead of being a maximum, igg)-/w*t vl(pi sun)b s dark. What is the (minimum) thickness of the plastic?    nm

  By what percent, approximately, does the speed of red lidka3;o5j( np0 9lx bpzght (700 nm) exceed that of violet light op(an3l9zp5 d ;jx0bk(400 nm) in silicate flint glass? (See Fig. 24–14.)    %

  A light beam strikes a piece of glass at a 60.: ive 7tvn+hw200$^{\circ}\,$ 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 wavelenm;vcyozsv,h-a3+ j.n gths, $\lambda_1\;=\;450\;nm$ 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 widm , ui6asb lz/.homj7u1z6btqnm -5+j e, what is the full angular width of the central diajj,nzl m/5to1q bm -6 bi6+7m.u zsuhffraction peak?    $^{\circ}\,$

  Monochromatic light falo7u*qglz*aro *9y .t mhs/.3b b93u cgdfmob .ls 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 slit thath6z0cla np 6 +vqjyvnc93z- 4f 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 illumina/aiy, 85xbg(ovv t kq9ted by 450-nm light. What is the width of the central maximum (in cm) in the t, bqkvov9axy /5i 8(gdiffraction pattern on a screen 5.0 m away?    cm

  Monochromatic light of wavex0kd*o uxt:3 rlength 653 nm falls on a slit. If the angle between the first bright fringes on eitherkx0x3d u*r: to side of the central maximum is 32$^{\circ}\,$, estimate the slit width.    $\mu m$

  How wide is the centrn 2vima/; m ,/j de7*vwtwz*bmal diffraction peak on a screen 2.30 m behind a 0.0348-mm-wide b wndvw/ ,e jv m2m*m7*/tiz;aslit illuminated by 589-nm light?    cm

  When blue light of wavelength 440 nm falls on a single slit, the d 3t3 r5r-muivfirst dark bands on either side of center ar im3rutv5d- r3e separated by 55.0$^{\circ}\,$. Determine the width of the slit.    $ \times10^{-7 }\;m$

  When violet light of wavelength 415 nm falls on a sis5 juxh yliw )s71s2p-kigj+ /ngle slit, it creates a central diffraction peak that is 9.j7ss)p5 g/2hxiwi yks -jlu+ 120 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 4.0 cmppt)2/m+ybyd)qj8c )rc8ggv ,ol9l w wide on a screen 1.50 m away, what will be the width of , pp)rc 2ojwgg/ vlty+9c 8y8m)b)lq dthe diffraction maximum for light of wavelength 420 nm?    cm

For a given waveleng ttqs6o+frl1: th $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm light produce a second-order maximum when agpaac84xi2q,ip.- o6cu 4jpdxu :ne8j6 5 mrfalling on a grating whose slits,844oj2.pp 5ixjxn8 aap cidmrqe-ugc :6 u6a 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 third-order oczu 6zk : 2iiy nizc5y8r98.ndecurs at an 18.09ni8z2yizc. 58:k6i deyu nrz$^{\circ}\,$ 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 gratinxkx 0fm 6y)b8vg is observed at a 15.mb )fk0xy68v x5$^{\circ}\,$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction grating ha,zqcq+s6he6zs 7i9 uz:hpj )j s $ 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 normallyh erq70po20ld 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 th*hov 9l5-yzpt**hiq;x 3v;(gua rx xdat can be seen if a grating with 6000 lines per x;;*tv gh 5i(ryqx*hl oa p9v*3z xud-cm is illuminated with 633-nm laser light? Assume normal incidence.   

  Two (and only two) full spectral ofge8e6-qzw1 gx3 6ip pds:b+wrders can be seen on either side of the central maximum when white light is sent through a diffraction grating. What is t6g:8 xsegp1ei wwq3 dz bpf+6-he maximum number of lines per cm for the grating?    $ \times10^{ 3}\;lines/cm$

  White light containing wavelengths from 410 nm to 750 ,syxx*s;su9snm falls on a grating with9s y ;sus,*sxx $8500\;lines/cm$ 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 cuai n/nmld/3e8 w26v 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 byxkhc39):owja8m,2 :dk x ero sa(w sx- 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 wavelenskb *tcmm ren-6k2./ egth is most strongly reflected at the center of the outer surface when illuminated normally by white lightckre *- nt.6ke2m/smb ? Assume that $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringes in Exampr3xer mf6ksf p18;) txnlv3d2le 24–8 if the glass plates are each 22tdf;m13vr) skrlx8pe6n xf3 6.5 cm long?    cm

  What is the smallest thickness of a soap filmnv: x9qg, mnrfqb.k *4 $(n\;=\;1.42)$ 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 * rr,qkbbxwjo n8mn5 5yr1* y1yellow ($\lambda\;=\;570\;mm$ 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 dark spot mn7p2g-wkvezw3 s+. u 6cw )swat the center) are observed when 550-nm light falls normally on a planoconvexv 7wzgw3-w s.n e26wc+u)pm sk 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 of opticalla*ly m72omv v )7tnzg/y flat glass, as in Fig. 24–33. When light of wavelength 670 nm is incident normally, 28 dark lines are observed (*v2/gl zo77ytm)manvwith one at each end). How thick is the foil?    $\mu m$

  How thick (minimum) should : sfp6dt,qb+;zqdl0y the air layer be between two flat glass surfaces if the glass is to appear bright when 450- q,+;qf dsp06zldy:bt nm light is incident normally?    nm
What if the glass is to appear dark?    nm

  vA piece of material, suspected of being a stolen d rqibb8srfrs8soq li37 2*y-,iamond $(n=2.42)$ 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 alcoheeg b)3lz 2nv9ol $(n=1.36)$ 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,*twjfbbf/ gt9 - g*bhv+,gm* t 4z2gre the diameter of the eighth dark ring decrea2*v wgtrzf+9,bj* *g f hmb4-/btt eggses from 2.92 cm to 2.48 cm. What is the refractive index of the liquid?   

  What is the wavelength of the light entering an interf3ni9yp+tj/e*l. ;yrza.n qs kerometer if 644 bright fringes are counted when the movable mirrjr*n+peiy; s3 . n.yz/9al ktqor moves 0.225 mm?    nm

  A micrometer is connected to the movable mirror of an interferometer. a)4 f/dp tla99(g7.ci op7drjhv prg :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 thickness o)t/fgpa ij7lrcpv:hg ( .od4r 79p a9df the foil? The wavelength of light used is 589 nm.    $\mu m$

  How far must the mirror e9m1l yme dl9vx66i7u$M_1$ 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 interferomxj vp /pjm6k 24rcn5 nk.c,f3seter (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. Calcu rfn6p4vxm,3cnjk2c5p. k/jslate the index of refraction of the gas, assuming that the interferometer is in vacuum. $n_{gas}$

  

  Two polarizers are oriented ag)*ue4 g3:7spkzj ,7jp t cnkut 65$^{\circ}\,$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s angle for qkxos:8dvl*ij* - )/ds vq7d qnjp :a3an air–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerged in water if the l3 k imktnur +cxrvz,l.tu+:-3ight is hitting thx3.utlrkku,zvm t+ c:+ n r3i-e diamond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the light8m-t, qmhir -. vjm7vt passing through them is a maximum. At what angle should one of them hm-t8qv 7vm.r,-ijmt be placed so that the intensity is subsequently reduced by half?    $^{\circ}\,$

  At what angle should the axes of + l6sgri4h2k .ckyjs ;two Polaroids be placed so as to reduce the intensity ofck.+ 2;ks ish 6jgylr4 the incident unpolarized light to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are ox4mc4elq; : srwc x k4yaxv01-riented 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 orien x0/tcbcabf7l 8)al,fted 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 off th85t juv:-p *hew4/.tme wysd pe surface of water for light coming from beneath the surface? C54* t/e- u hjwem dspv8p:.ytwompare 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 passes through five successive Polaroid2/i osk*tt m+k sheets, each of whose axs2k/ tm*tiko+is makes a 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength eaos0l9 90zgp.xzfx 1$ 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 r 7-ey y: vhdeuc:/dfn-u5 4wxseflecting from mountains or airplanes can interfere with the direct signalxhf4 und-s yve:-57:ec /wydu 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 pasp .nfzqp+i )5sses through a diffraction grating with pfi )znsp5.+ q$ 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 throughy (t:dme 82lut 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 dl8m:2t (yeut 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 broadcastsm/r( iefzt rd81rn7 q9 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 exten78red 9 nz rqfrt(1mi/ding 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 ff*7nkwb2swq1 e tl*n )0p v:gtrom an outside doorway 0.88 m wide, and blows a whistle onks0v2pl:e n* 7*w q wtb1)tfgf frequency 750 Hz. 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 zbric/. m7ld*6e/ zyt(+ awn; qaqje4a 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 series of parf esjcz48 m5*lallel lines across them. When normally incident 460-nm light is reflectes8zm5c fj*le4 d 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 centimete 3nnv4ql6;tcj,gqx7 0) uv lcgr must a grating have if there is to be no second-order spectrum for any vitx,n63c);c7gujgn 0vlqlq4 vsible wavelength?   $ lines/cm$

Show that the second- and third cm831nr7)nr j nrvwwbh5 *s1y-order spectra of white light produced by a diffraction grating alway 8 5 jyw)br1rr1scvnh73*wnmns overlap. What wavelengths overlap exactly?

  When yellow sodium lf bjq,732dw/ j elul6hight, $\lambda\;=\;$ 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 grati2e*rqc3bsxc(,u zqozwohuig,, dn;a ( t(/ i, ng with and the pattern is viewed on a screen 2.5 m from the grating. The incident light beam consists of two wavelengths,nwhzu tic r,, izuq(o32cde( ,x,o;*gs (q/ba $\lambda_1\;=\; 4.6\times10^{ -7}\;m$ 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 mm.p . - lrb-g*m.j,ls5*5q/yv u yc kajal;lcvaterial if a minimum of 150 nm thickness of it, when laid on glass, is needed to reduce refle-llja/..yjpc5 ;cq uy-kas b.v*rl mg5v*m l ,ction 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 wavotj z/bxe/,e 7elength is incident normally on a thin sheet of plastic film in air. The reflece,/ ezo/7 jbxtted 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 an*ufrkz/w4 5amg it5 ;kti-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 foowkxg eg4 42; ppzypo+ j9)g:gr the air layer between two flat glass surfaces if the glkygpjz: 9wgpgp ) ;44eo2+oxgass 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 lvn5rk*4(u zf:75 avos+hygaw ight transmitted through a thin film layered on a flat piece of glass. Draw guah5*7 (yo+5 vnfrz:svaw4ka 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 the maxima and to zero.
24-30
24-36

  At what angle above the horizon is the Sun 6y*w2mtodu7o* ol9qkwhen light reflecting off a smooth lake is polarized most stron962*koy m7t*qu wo lodgly?    $^{\circ}\,$

  At what angle should the axes of tw3 bo gaqmh2fr /mt2;s2o Polaroids be placed so as to reduce the intensity of the inoh3/2m gsat;m2r2fqbcident 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 tra9n:,pyumz fq )nsmission axes are at right angles. A third polarizer is placed between the first two so that its axis makes zp:un,)m f9yq 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 successic pxwv28e)thmf;x 7hc* -xwb/on 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)zw:w.oll*eu a slit of width 1.0 cm and is pointed at the Moon, which is approxiw:* zlelo)uw.mately 380,000 km from the Earth. Assume the laser emits waves of wavelength 630 nm (the red light of a He-Ne laser). Estimate the width of the beam when it reaches the Moon.    km

  A series of polarizers are each placed at adrl(v kfq7, ,1ldcuu7. crh5n 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 5iai ,s7z+8( 2 qm9q6 svebyevbg9uko $(n=1.34)$ 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 ra)xa b.b aar.60 myzbho96ae-s diating 6.0-MHz radio waves in phase with each other. They are located at0)m asz -ya6x9arhab6.be o.b 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 650 nm, enteg/mw)j6rslfu :rs13 0 a3doxswh2y 9urs a silicate flint glassh )fs1suda /3w g ulw39roy2:6xmsr0j 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 flou p)vffd3d/l/-: qyqcc8k c1 0kx 9y3h sx+blat 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