Does Huygens’ principle apply to sound waves? To water3eh7tga n q;-e waves? Explain.

What is the evidence that light is endo t++du org0,-v h-ehergy?

Why is light sometimes described as rays and sometimes as wnc,,etmtc* (rkt n; b7x7nx a7h ngi+;aves?

We can hear sounds around corners, but we cannot see around cornerqi:e.io rrzd f9ho17/ s3uv4 us; yet both sound and light are waves. 1iid hu e749r /.qo:fvro3zu sExplain the difference.

If Young’s double-slit experiment were submerged i 2cl/t+5lz dfye,*fzs n water, how would the fringe pattern be changeyt l/f,2 czsldf+5ez* d?

Monochromatic red light is incident on a double slit, and the inter4dhusy/ zk; 6y 5dfmb-ference pattern is viewed on a screen some distance away. ; fsyhy6-dd5zm u/b4k 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 destructive/i-u: mcvy 7qhly interfere if their path lengths differ by how much?i h-:7mvyc/uq

Why was the observation ofyir r+bvzw yx6b:.m7y-hss;) the double-slit interference pattern more convincing evidence for the wave theory of light than the observation of diffs )bhr ;xyb yswry6-+vzm:.7iraction?

Compare a double-slit exp bqnixff auz46o5352 deriment for sound waves to that for light waves. Discuss the similarities and dibo3q 2ff nd4 xz55i6aufferences.

Why doesn’t the light from the(-4mos vl1hyl(nf ,ku5 6luee two headlights of a distant car produce an interference p4 ( -eh f6ylselo(l1vmuu ,k5nattern?

Suppose white light falls on the two slits of Fig. 24–7, but one slit is coujxw9h+h;ak :vered by a red fijh;uka w:+ xh9lter (700 nm) and the other by a blue filter (450 nm). Describe the pattern on the screen.

When white light passes through a flat piece of window glass, u81yr:dwpz m k k:yp.rp7x,s(it is not broken down into colors aszw:py krds1 uxp(k,rypm8: 7. it is by a prism. Explain.

For both converging and diverging lenses, discuss how the focal length for rk+uvx 97amnt: ed light differs frm:vxk7a 9unt+ om that for violet light.

A ray of light is refracted through three different materials (Fit tc6nn)j -j 5xn9t6v;vlwfw 2.fd,alg. 24–55). Rank the materials according to their ind.-;5nt tl2 9, )wc xjffvtvl dnj6n6awex of refraction, least to greatest.

Hold one hand close to your ey50 b1s5 gbjlv+0mgluy e and focus on a distant light source through a narrow slit between two finjysl l1 m00g55+b ugvbgers. (Adjust your fingers to obtain the best pattern.) Describe the pattern that you see.

What happens to the difffm8.qsfy0 6y8bmlf; oraction pattern of a single slit if the whole apparatus is immersed in (a) water, (b) a vacuum, inst 6mylq s0f;o8 .f8fbymead of in air.

For diffraction by a single slit, what is the effect of increasing (a) 1b5/fxb3kz4 -xp sjjfthe slit width bx /x4f1b-sjpzj3 kf5, and (b) the wavelength?

What is the difference in the interference patterns formed (a) by twff3y q v p)0kx2d1kf0io slits $^{-4}\;cm^2$ apart, (b) by a diffraction grating containing $10^4lines/cm$?

For a diffraction grating, what is tsnu*n yek *c3;,ca/q( ngcww2he advantage of (a) many slits, (b) closely spaca c,g2ncekq*( /*3w wu ;nscyned slits?

White light strikes (a) a diffractjnp 3gp.k6 8; 8tnaky5efkv+eion grating, and (b) a prism. A rainbow appears 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 casepgv5;j3p 68 f nnkety.ke+ka8 ? Explain.

For light consisting of wavelengths betjuz,+c d81 nywc/ sxq/ween 400 nm and 700 nm, incident normally on a diffraction grating, for what orders (if any) woudcc sw ,1yz+/ju8x/qnld 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 li bro44ujn9s0 kke a soap bubble and not for a thick piece of glassju0ksnb4 o 4r9, say?

When a compact disk (CD) is held at an angle in white ligh+/lbtn lw01ej t, the reflected light is a full spectrum (Fig. 24–56). Explain. What would you expect to see if monochromatic lighn+j /0tlwleb1t was used?

Why are Newton’s rings (Fig. 24–31) closer togetheq(i5o .(h ex, (qdp:l1edjuclr farther from the center?

Some coated lenses appear greenish yellow when se5tk b+q u+rf)ben by reflected light. What wavelengths do you suppo+bt+5q u )fbkrse the coating is designed to transmit completely?

A drop of oil on a pond appears bright at its edges, where itv/45 hvausfm3qa 1/ug s thickness is much less than the wa14mvsh gfa3 q uu5/va/velengths of visible light. What can you say about the index of refraction of the oil?

What does polarization tell us abouidx1*wb j ;3yft the nature of light?

Explain the advantage of polarizedo;df jw xpgvb38xix7m 7y1woy; yk6.7 sunglasses over normal tinted sunglasses.

How can you tell if a pair o.t4ha-v7dc z ot4 zk0gf sunglasses is polarizing or not?

Two polarized sheets rota.5(n--rxy ,o 8 mg9nnbplcmq dted 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 /;t+kno n- yogif the Earth had no atmosphere?

If the Earth’s atmosphere were 50 timht*4w y6+kqla5zooe hp0h *- oes denser than it is, would sunlight still be a h *l+ht*oh eky56o4-0zwp qowhite, or would it be some other color?

  Monochromatic light falling on two sl n tzg1qv /3g,2 q+ax7navhn/h/cts+b its 0.016 mm apart produces the fifth-order fringe at ann +/ 7,2nhtggc1av/xtq q+/hab3 znvs 8.8$^{\circ}\,$ angle. What is the wavelength of the light used?    $ \times10^{-7 }\;m$

  The third-order fringe v mutm,;gq b5+ jh-z;v0s csdcm,)zm4 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)+ b;ik az 8;jt8yiuy /7 fz ikra/o:rr7uwq:k 0.048 mm apart. Successive fringes on a screen 5.00 m away are 6.5 cm apart near the center of the pattern. Determine the wavelength andr tf ka ba)wy/ kuo7 :+;i8zi8;7/uj:ikyrrqz frequency of the light.
$\lambda\;=\;$    $m$
$f$ =    Hz

  A parallel beam of light from a He-Ne laser, with a wavelength 656 ntjr i;j89cawl3k +za2m, falls on two very narrow slits 0.060 mm apart. How far apartr 3w+;tlz9ac2j ai 8kj 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 ;p j;lvg,3pqtg2n 4g/z88 rsrwrtl(m pattern in which the fourth-order fringe is 38 mm from the central fringe on azj; s ,q2rgw8rrl/; g(m8t4 ltppgv3n screen 2.0 m away. What is the separation of the two slits?    mm

  If 720-nm and 660-nm light passes through two slits 0.58 mm apart, how far ay/1pc j*xt0eijo* ;+c/ .fk gu8y5 c 8jokawxspart are the second-order fringes for these two wavelengkg c c.oijo /8cj*xj+ ky8f01saep*wuy;xt 5/ ths on a screen 1.0 m away?    mm

  In a double-slit experiment, (y0fb.ts ey)n it is found that blue light of wavelength 460 nm gives a second-order maximum at a certain location 0. (b)yte nyfson the screen. What wavelength of visible light would have a minimum at the same location?    nm

Water waves having parallel crestm601cru3 5)8t - jcslu+ hhnj xnnbsw(s 2.5 cm apart pass through two openings 5.0 cm apart in a board. (nsnxb-5)j j8mc0+uh 6wl3t r chu1 snAt a point 2.0 m beyond 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 slit in Fig.*k1k ya :caqf: 24–7 so that the two wavesf1c a yka*k::q 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 waveleng*k/yk(/tze k6e eprk2da7 x 1sth 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 proje7p6e kzer ysx/d(2/kkkt a 1e*cted 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 separate l6mhiuesqb y8 g3gsq44xc-9stw2.2hd by 1.0 mm are illuminated by 544 nm light. Find the distance between adjacent br4 82.qg23 6hl -ehgbmytusss4x qi c9wight fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480m11 0ro7.ws)ii9zg:. dhhx htmd .g cx nm in air falls on two slits $6.00 \times10^{-2 }\;mm$ apart. The slits are immersed in water, as is a viewing screen 40.0 cm away. How far apart are the fringes on the screen?    mm

  A very thin sheet of plastic (n=1.60) colum.7.+b3 i vo,gmf pdvers one slit of a double-slit apparatus illuminated by 640-nm light3p..imul7ogb, v+m df. The 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) excqj8u 15 gp1 :9hryhi8h cxym m*pq01kweed that of violet ligh:q uy yq8pprg8k05hxh1 91*icm1w jhm t (400 nm) in silicate flint glass? (See Fig. 24–14.)    %

  A light beam strikes a piece of glass at a 2i la9n:: e drz7oe)ib60.00$^{\circ}\,$ 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 lighb.alxk .x.n 6kt containing two 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 sli6 4i8we9f gbztt 0.0440 mm wide, what is the full angular width of the central difg8w 4 69efbztifraction peak?    $^{\circ}\,$

  Monochromatic light falls on a slit thmug 4r0 upp9t;at 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 that is 50vg+hg)oe xrft8fq1$ 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 i kxa902d ,uxkns illuminated by 450-nm light. What is the width of the central maximum (in cm) in the diffraction pattern on a screen xk2k,xuda90 n 5.0 m away?    cm

  Monochromatic light of wavelength 653 nm falls on a slit. Ixhw73o(b 90p x*5esynr 4ypr ef the angle between the first brigery0*e 3rop(s9nb4 w pxyh 5x7ht fringes on either side of the central maximum is 32$^{\circ}\,$, estimate the slit width.    $\mu m$

  How wide is the central diffraction peak o *8upu;)xlmw qn a screen 2.30 m behind a 0.0348-mm-wide slit illuminpw ; mu*ulq8x)ated by 589-nm light?    cm

  When blue light of wavelength 440 nm falls on a single slit, the first dar.:e- /tz rcjnhk bands on either side of center j zr-:ent./ chare separated by 55.0$^{\circ}\,$. Determine the width of the slit.    $ \times10^{-7 }\;m$

  When violet light of wavelength 415 nm falls ovak //s;57z*/ bae;ymjs zv f 6.ytmlyn a single slit, it creates a central diffraction peak that is 9.20 cm wide on a screen that j m/7/;lsfa* /6ayk5zet mbvvyy; z.sis 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 cm vc8y3v3(ghvmr 5 2dd7 mk)r8o5m xq6noopa :pwide on8m6hkn y v:v8 gmd7)r od3oq23orv(5 pcpax5m a screen 1.50 m away, what will be the width of the diffraction maximum for light of wavelength 420 nm?    cm

For a given waveleng9gh hj-l 5*tfcth $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm ,-. ku dyo:hgn2qor q-light produce a second-order maximum when falling on a grating whose slitd ,.r- gqouk2h:y no-qs 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 hpwp7f 9oc8 (48txbz1q ob;azkave if the third-order occurs at an 18.zqcb(w9o8 fkt7xbao8; zp 4p10$^{\circ}\,$ 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 fa7(jmklcer)ob*w493 d ptn9 k vlling on a diffraction grating is observed at a 15c94 ktj7opewdv 9)mb*(rn3kl.5$^{\circ}\,$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction grating has 6n) zp/u tv,ld$ 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 h)- acdsrh2 ,kon 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 ordez6lb cvz j:(a.r that can be seen if a grating with 6000 lines per cm is illuminated with 633-nm laser6vzcz(: abjl . light? Assume normal incidence.   

  Two (and only two) full spectral orders can be seen on either side of i6he,k0od)y rqn6*s7lhvuue* fcfds6 8 p6g6the central maximum when white light is sent through a diffraction grating. What is the maximum number of lines per cm for the g6kdh) vsd06u,g 8c h67f6ouf y6e*leq*isrp nrating?    $ \times10^{ 3}\;lines/cm$

  White light containing wavelengths from 410 nm to.fok: 2 j)pmtqgd/;hsw.qw)7y pt x v*9-cznb 750 nm falls on a grating with 27h ;/ q)csw: .tyv.domjkztx g9 wfpq*b)pn-$8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which produces mcy2 u,.c z3wuqonochromatic light 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 areb3w zd/qb 4 re8.m5ix*eyfr6u 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 12w 3a jhl 9fytz4jvt;140 nm thick, what wavelength is most strongly reflected at the center of the outer surface when t l;3t h9vfwyazj1 4j4illuminated normally by white light? Assume that $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringes ij:.qa y6 z,klyn Example 24–8 if the glass plates are each 26.yjqay k :,.lz65 cm long?    cm

  What is the smallest thickness of a soap filmygph8 s:x3gsxl 1,zz8 $(n\;=\;1.42)$ 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 yelum: 6ht s9 2zlm3 )wa)wprw4qqlow ($\lambda\;=\;570\;mm$ 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’she8 bfq 6y 2:lnx3hfo h+1p,eq rings (not counting the dark spot at the center) are observed when 550-nm light falf2hh: ohfe+16x y qlq8nbp ,3els 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 of two pieces of optical8 n,/53ykncxz 3/5ylvwh ,w7 q vnipnjly flat glass, as in Fig. 24–33. When light of wavelength 670 nm is incident normal/5/iwznvnk5l n3 pjvyw yc x7,3,q8hnly, 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 between two flat glass sur+ 8nzm3vdf +ep1 iz yjmgk2*9wfaces if the glass is to appear br p+m2inm d 8kwfye*1+zz vj39gight when 450-nm light is incident normally?    nm
What if the glass is to appear dark?    nm

  vA piece of material, suspectedl0(; ctbipngv5n0 t1 fz aop5 es6*6sv of being a stolen diamond $(n=2.42)$ is submerged in oil of refractive index 1.43 and illuminated by unpolarized light. It is found that the reflected light is completely polarized at an angle of 59$^{\circ}\,$. Is it diamond? ----待选择----yesno 

  A thin film of alcohol zst-ijd/ 6a / p7y1nto$(n=1.36)$ 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 diam7t8 )ay) 1ux3p q2vvpqc3oldoeter of the eighth dark ring decreases from 2.92 cm to 2.48 cm. What is the refractive index of the liqui 1u to)a8qvoc32q3yp) dvxl 7pd?   

  What is the wavelength of the light entering an interferometer if 644;c+79)ipecl .psxlsk bright fringes are counted when the movable mirror mov e)scksl.;7c +ppxil9es 0.225 mm?    nm

  A micrometer is connected to the movable mirror of an interferometer. When thmg quh*c1py0.h /-ccht5u0l ce micrometer is tightened down on a thin metal foil, the net number of bright fringes 0 y0 5l ch*1-.ughupmqct/ chcthat 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 mirror tfl26jd u13ug $M_1$ 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 interferometql xd uo xo:5u)dqmv18z6l00 oer (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 referencex v5zu : ld 08qdo0ul)oxm6oq1 line. The light used has a wavelength of 610 nm. Calculate the index of refraction of the gas, assuming that the interferometer is in vacuum. $n_{gas}$

  

  Two polarizers are oriented atrvgwb.r -:tqwca)td7.zn+ p4 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–glaim62xn-/5kb w:3i0 cpir5tcu p vcr i/ss $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerged in wat-3.,br r0yfnl i szkk)i/ dp:-bw/ zqzer if the light is hitting the dia3l0bf)iyibz/k-z . ,nr r d-:kqpzw/s mond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the light passingh-y4k */okumsq h2d1p through them is a maximum. At what angle should one of them be placed so that the i 1oumh d ph-sy*kqk2/4ntensity is subsequently reduced by half?    $^{\circ}\,$

  At what angle should the axep0g3c hir try,q*-k ;vs of two Polaroids be placed so as to reduce the intensity of the incident unpoqhy,-*cr; rv0kpti g 3larized light to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oriented+.0ljxi j(o j07z3)puxbdlp c 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 as5y1n 6d8op smt 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 reflectiony .a(e:aupu 2r 4n3nccs off the surface of water for light coming from beneath the surfaceun: (r4 ac. ua2cp3ney? 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 passes through five successive Polaroid sheets, each of whose tp4 wvy,h4 s+caxis makes ,pv4t+ hwcs 4ya 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength g-zjuh y2sd;r28.,n.ot b lbh e (p5do 9aux-m$ 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 refle2*nakplh29q c x9ny2z cting from mountains or airplanes can interfere with the direct signal from tnxn22k9* q2hp 9 zyalche 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 diffraction grating withfg-- h, yya jj.ek-c8z ,.k-e c-yzyh gaf-jj 8$ 3.00\times10^{5 }\;lines/m.$ The wavelengths of the three lines are $ 6.56\times10^{-7 }\;m$ (hydrogen), $ 6.50\times10^{ -7}\;m$ (neon), and $6.97 \times10^{ -7}\;m$ (argon). Calculate the angles for the first-order diffraction lines of each of these sources. $\theta_{h}$    $^{\circ}\,$ $\theta_{n}$    $^{\circ}\,$ $\theta_{a}$    $^{\circ}\,$

  Light of wavelength 590 nm passes through two narrow slits 0.60 mm apart. The 5q+y8i6gz 0ant60 s,wobed ltscreen is 1.70 m away. A second source of unknown wavelt s8wez 6ayt+ ,5gd06obln0iq ength 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 at 102.1 MHz broadcasts fr jlwyju08v m+ nn.p9:iom 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 a0vwumi8jn9 j y+p.:lnt 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 out .)1hw+a +qc4cd1vgdc1 u knruside doorway 0.88 m wide, and blows a whistle of frequency 750 Hz. Ignoring reflections, estimate at what angle(s) it is not possible to hear the whistle clearly onu++gdccw.kch 1r 1)avqnd u1 4 the playground outside the doorway.    $^{\circ}\,$ either side of the normal.

If parallel light fall 6o .i(l(aoj l9;qriiks on a single slit of width D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a serie.-)l) kwz2iurg**)jc vd.1e ce dvvaws of parallel lines across them. When normally incident 460-nm light is reflected from the wing, t))ci1)d-2 we.zrj *wvl gad.vv*u c kehe 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 a35k ukcj/(zk if there is to be no second-order spectru aju /(5kz3kckm for any visible wavelength?   $ lines/cm$

Show that the second- and third-order spectra of white light prod ddafb*w8cb/4 uced by a diffraction gra f4bd8ab/w*d cting always overlap. What wavelengths overlap exactly?

  When yellow sodium light, miv8f7ge54u 9lu :iyr$\lambda\;=\;$ 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 pattern is vd-jg2 /(wcqdb4bc-qb ozm 0*viewed on a screen 2.5 m from the grating. The incident light beam consists of b*g/b0zcjq d(qo m-bv -wd4c2two 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 cleardvhk(r 96vch: i+m o:eb m1xp2 material if a minimum of 150 nm thickness of it, when laid on glass, is needex vc6mbh:poim9 +ev1h k:2r(d d to reduce reflection to nearly zero when light of 600 nm is incident normally upon it? Do you have a choice for an answer?

  Monochromatic light of variable wavelength is incident nc);ed- jqr;cnormally on a thin sheet of plastic film cn qrec;-j d);in air. 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 k35xt x0pzz0q6 ) grs5c1.oho a zst/wan anti-reflective coating $(n=1.38)$ applied to a glass lens in order to eliminate
(a) blue (450 nm),    nm
(b) red (700 nm) reflections for light at normal incidence.    nm

  What is the minimum (non-zero) thickness for the air layer between tcf+hhvr*+jbng/ a75p:9ownf ajf- g,wo flat glass surfaces if the glass is to apagfh :+fgoj c7np-ran5b,wh/vf j *9+pear dark when 640-nm light is incident normally?    nm
What if the glass is to appear bright?    nm

Suppose you viewed the light trjmc38 b,7 oho2tyay 8qansmitted 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 m8o qt,boy3h2camyj8 7inima compared to the maxima and to zero.
24-30
24-36

  At what angle above the horizon is the Sun when light reflecting off a s gc5+0c. wvrweer7 /ejmooth lake is polarized mostrr+/w0 eve.cejc gw57 strongly?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so as qsx94*k taq6uyb 7p /cjxu4kz)x 85bi tnd3n5to reduce the intensity of the ibxps57ti x89jk 4kqnnuz5tyc4 u 6)a qbx3*/ dncident 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 transmissioczomoae6 ev;+foj:l 70us :;w 7vrf1zn axes are at right angles. A third polari1e6rwm:;fca uoov oz7z0el :v+;f 7s jzer 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 succession with their c f8+j ;cy5za 4ied ky0h9aa8aaxes 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 xx z7gvn;y- +-t,8sadwsd :bhof width 1.0 cm and is pointed at the Moon, which is approximately 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. :ndh dvb+stawxy- 7x-g s8,;z    km

  A series of polarizers are each placed at azhdbzlk53 v4z7(m m w- 10$^{\circ}\,$ interval from the previous polarizer. Unpolarized light is incident on this series of polarizers. How many polarizers does the light have to go through before it is $\frac{1}{4}$ of its original intensity?   

  A thin film of soap w gfy)no crc 9cq:(nt4 lcs.9,$(n=1.34)$ 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 each orh.5i x i(3(qb9qe9sqlg 4xnl ther. They are located at point s(9q ( l49n53rxixebqiq hg.ls $S_1$ 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 6..yzmq t8wv3-r 5 qali50 nm, enters a silicate flint glass equilateral prism (Fig. 24–58).qa.t3-l v8ry5m.qiw z
(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 o46gp oe 8ipsu(y* 5gkone 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