Does Huygens’ principle apply to sound waves? To water waves? Exp0i38(rqxihau:nk- m m 5q ba,clain.

What is the evidence that httz+l2 u45 k,iat ma1light is energy?

Why is light sometimes described as rays and sometimes a) s**:-, t. taclwtrwz(m zkjequ a;5ws waves?

We can hear sounds around co0a iq/ )s*o8-a*fzgsf0b b ezgrners, but we cannot see around corners; yet both sound and ligh-s zz80sa)*og feqbbgif/*0a t are waves. Explain the difference.

If Young’s double-slit experiment were submerged in water, how woq9 t ctpoc,kjefwxe+06 yw: :.uld the fringe pattern be changco:w. e w0j kqetcf:9y,x+t6ped?

Monochromatic red light is incident on a double slit, and ti:0hd a28qz)xc1 qkuw 0zj9fre 4rmb3he interference pattern is viewed on a screen some distance away. Explain how the fringe pattern would change if tmi1w3:0 b0e)j 2zaqr4 zkrfud9 cxq8hhe red light source is replaced by a blue light source.

Two rays of light from the aj: ;sq m3gbyg7 al sx)iqv31:same source destructively interfere if their path lengths diffex:l:y);7q3ijvasmbq 1s3 gg ar by how much?

Why was the observation of the double-slit interference pattern more cd 9s0t */g-qx5 synerjqm9i*aonvincing evidence for the5 0/x qmy9nrd9es* j -g*staqi wave theory of light than the observation of diffraction?

Compare a double-slit experiment for sound waves to that for light wav uydc*qm,cxdb8s:i)c oyuas(b0 55s;es. Discuss the similarities and difq)(:dcoxs *50dby cs u5,c a;bm8syiuferences.

Why doesn’t the light from the two headlights of a disdtxq u61; :yestant car produce an interfe:dy t6s1; quxerence pattern?

Suppose white light falls on the two sliingm6/:b b2oy ts of Fig. 24–7, but one slit is covered by a red filter (700 nm) and the other by a blue filter (450 nm). Describe 6yg2 ob: bi/mnthe pattern on the screen.

When white light passes through a flat piece of p)r qwp/xo.bd uj.h us(fb8-+;. ljk l:hnp y:window glass, it is not broken down into colors as qhy:f)k + hw8u.- xr snp;op(dulbp/j. jb:l. it is by a prism. Explain.

For both converging and diverging lenses, discuss how th ld(r1+9sbgns e focal length for red light differs from that for vigbls91d(s+ n rolet light.

A ray of light is refracted through three different materials (Fig.webrbrz c-972 24–55). Rank the materials according to their index of refraction, least to great-9 27werrz bbcest.

Hold one hand close to your eye and focus on a distant light source through ye/ a1d.x p 6cdvl9d+pa narrow sl6dv +dl9.ey 1dp/cxpa it between two fingers. (Adjust your fingers to obtain the best pattern.) Describe the pattern that you see.

What happens to the difn+pc qlem5)r(y5ix q:fraction pattern of a single slit if the whole apparatus is immersed in (a) water, (b) a vacuum, instead of inq n 5cq l(+xrm:5pey)i air.

For diffraction by a single slit, what is theg-o0c5kvdwt;1mwy3:)gop q t effect of increasing (a) the slit width, ak1t)opgd -5ot;:wmy g0 3vwqcnd (b) the wavelength?

What is the difference in the interference patterns formed (a) by6k* etw)p+1h4h ppg cuc/i9oo 1rwq9c 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) closel7uz 1zfsaw90 ry4x(s 8b7gqf 8eh5we hy spaced slitxe98f z7su5 1f q we wh74bg(rzya08shs?

White light strikes (a) a diffraction grating, and (b) a pri:bqf yzroy. 4ys)6wo.wc6w0yy o 8 ff1sm. 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 case? Explair6 1yo wzyw:yosq6 .cfy.8f0 4y of)wbn.

For light consisting of wavelengths between ypq//;ycy 5aqs44h1 ffon(y v 400 nm and 700 nm, incident normally on a diffraction grating, for what orn chpfs 14;vq(/5yyf/a yoyq4 ders (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 soalo50val c;cx+/i9z wa:i+bet p bubble and not for a thick piece of glass, saye05 ctxcv+i9/o+l b wlza ;ai:?

When a compact disk (CD) is held at an angle itn8x1 ili1h +on white light, the reflected light is a full spectx lt1n8+hi1 iorum (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:rh 8q vf0,rnr from the center?

Some coated lenses appear greenish yellow when seen by reflected light. What n he699s gpl*qj.m 9qo (cmjc3wavelengths do you suppose the coatingje *9n9mol qjpmc hg(.963cs q is designed to transmit completely?

A drop of oil on a pond appears bright at its edges, wher zri* ,6t9f q) sw9nzj:xuq5a* sme6hqe its thickness is much less than the wavelengths of visible light. What can n9zj5 ze* raf wsqt):*xhq ,9qm6usi 6you say about the index of refraction of the oil?

What does polarization tell us abocza5ofv79h 4c 8p rhd4ut the nature of light?

Explain the advantage of polarizmx edf2qh1- h27 nlh3sed sunglasses over normal tinted sunglasses.

How can you tell if a pair of sunglasses is polarizing bcwklf)3 dbhq14wb 5 4v -cet8or not?

Two polarized sheets rotated at an angle of 909 nh 6eh+;j b6,uvroqwv3q i8b$^{\circ}\,$ with respect to each other will not let any light through. Three polarized sheets, each rotated at an angle of 45$^{\circ}\,$ with respect to each other, will let some light through. What will happen to unpolarized light if you align four polarized sheets, each rotated at an angle of 30$^{\circ}\,$ with respect to the one in front of it?

What would be the color of the sky if the Earth had no ah1t9r4br8 cq ntmosphere?

If the Earth’s atmosphere were 50 times denser than it is, woumm1zkms h-v .e)kz7 p6c;)ggpld sunlight still be white, or would it be s)ksz)pmep 7 .1 gmmg6-ch;z kvome other color?

  Monochromatic light falling o9qo*bxf e:nzyzzc;o;qteo .zu )i *,smbj 3+6n two slits 0.016 mm apart produces the fifth-order fringe at an 8.;z,sq6j3c: xzz )yuo . qtf9 b**;eibz+n omoe8$^{\circ}\,$ angle. What is the wavelength of the light used?    $ \times10^{-7 }\;m$

  The third-order fringe of 610 nm light is observed jyko wtzqem v.;2)2+sat 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 mm apart.sdrnxus -/ )r sb4m0/h Successive fringes on a screen 5.00 m away are 6.5 cm apart near the center of the pattern. Determine the wavelength and freq dbrx)ur4 s/0sshmn/-uency of the light.
$\lambda\;=\;$    $m$
$f$ =    Hz

  A parallel beam of light from a He-Ne laser, with a wavelength 656 nm, falmg iyxbn+*/( lls on two very narrow slits 0.060 mm apart. How far apart are the fringes in the center of the pattern on a screen 3.6 m away?+ xbn/y(*m igl    cm

  Light of wavelength 680 nm falls on two slits and produces an interferenca6 w1 i )(xm8govuv1pjfx e/cmi5)qw3e pattern in which the fourth-order fringe is 38 mm from the central fringe on a screen 2.0 m away. W1cp)/x) jx53 a1wv u( i6mimqveowf8ghat is the separation of the two slits?    mm

  If 720-nm and 660-nm light passes through-*f30fh s 1rv ,brywa. 4fiyatv6jz 4t two slits 0.58 mm apart, how far apart are the second-order fringes for these sv61-a4f rt*fraytbf j0 iy 4h.vw,z3two wavelengths on a screen 1.0 m away?    mm

  In a double-slit experiment, it is found that blue light of wavelength 460 n7g;f5vv0ui*-etmb zj m2v q9o .buk x1m gives a second-order maximum at a certain location on the screen. What wavelength of visible light would have a mitbu7qe ;vmf m-vjg5 xu*9 10i2kobzv.nimum at the same location?    nm

Water waves having parallel cresp .kck gbh)b04ts 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” directi 4p hg0kbck.)bon would there be little or no wave action?

Suppose a thin piece of glass is plac2n;pjsp g(b54zxn1ryl8d e5oed in front of the lower slit in Fig. 24–7 so tolgnz21nb(pepsd 5 x;458rj yhat the two waves 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 wave(8esgdc: /aerdnwxv e4/t -/u lk8 (zdlength 500 nm is located 12 mm from the central bright spot on a screen 1.6 m from the slits. Light of wavelength 650 nm is then projected through the same slits. How far from the central bright spot will the s48(l ewkd-g/ exd(/sveza ct/8ud n:recond-order maximum of this light be located?    mm

  Two narrow slits separated by 1.0 mm are illuminated by 544 nm,,1 s.vbk nyjs light. Find the distance between adjaces1, n.b ,jsyvknt bright fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 nm in air falls on two mng .kh xn;0*aslits $6.00 \times10^{-2 }\;mm$ 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 0kc-e0cukp*pn5qpa; one slit of a double-slit apparatus illuminated by 640-nm light. The center point on-0ck0 p5aqp *ke ucp;n 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) exceedju3( ,hw35lsksi 0 ioq that of violet light (400 nm) in silicate flint glass? (S5qjw(h3ksolsu0i 3 i,ee Fig. 24–14.)    %

  A light beam strikes4.bqdjk,p yp6 a piece 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 two qb8 kix e0h5hsc /x4iu46l9ktwavelengths, $\lambda_1\;=\;450\;nm$ and $\lambda_2\;=\;650\;nm$, enters the silicate flint glass of an equilateral prism as shown in Fig. 24–58. At what angle does each beam leave the prism (give angle with normal to the face)?
$\theta_{d1}$    $^{\circ}\,$ from the normal
$\theta_{d2}$    $^{\circ}\,$ from the normal

  If 580-nm light falls on a slit 0.0440 mm wide, what is the full angula :4joyjf)mdh*v*q.msr width of the central d f*j:. vmymq4o )hj*sdiffraction peak?    $^{\circ}\,$

  Monochromatic light falls on a slit th gr.;prjkpgb 57dw:hk*+i8m( leet+rat 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 h ae(t)ca0cl 7falls on a slit that is $ 3.20\times10^{ -3}\;mm$ wide. Estimate how far the first brightish diffraction fringe is from the strong central maximum if the screen is 10.0 m away.    m

  A single slit 1.0 mm wide is illuminated by 450-nm light. What is the width of b r(n 6pe6ho,7g ycn::jrq:blthe ce:lp 6cn:ebo 6yh,j7rg :b(nrqntral maximum (in cm) in the diffraction pattern on a screen 5.0 m away?    cm

  Monochromatic light of w,q sv i i208wqb pg9zgkzmk255avelength 653 nm falls on a slit. If the angle between the first bright fri5 9 ,vz 25pq z8mqkkigbg0wis2nges 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 m behind a 0.0348-mme ,mu8dihc g83-wide slit illuminated by 589-n8egcdm, h3ui8 m light?    cm

  When blue light of wavelength 440 nm falls ons7j7co 0zwo.jbquca27egb j px.:1k4 a single slit, the first dark bands on eitherwc7 c42e0..j :1bg u77oa poqz sbkxjj side of 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 slitv tx-g-fy,t3e uxj0 a8, it creates a central diffraction peak that is 9.20 cm wid8 -u-gfye,x0 vtt3axje on a screen that is 2.55 m away. How wide is the slit?    mm

  If a slit diffracts 650-nm light so thax(;ry *b *rpga :ptgtc;yl45r t the diffraction maximum is 4.0 cm wide on a screen 1.50 m away, what will be the width of the diffraction maximum fx y:rt c;gpgl (5yb*r;4r a*tpor light of wavelength 420 nm?    cm

For a given wavelengtr 5r.1,ccjj3ta utc6 yh $\lambda$, 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 falling h1yz i;v7xv2o oob+,j3fczf: on a grating whose slii b1 v z;fjhyxc2:ov,oo37+fz ts 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 p .tlb2s u2)auhp*gkh,kgjh ;5d k0q8grating have if the third-order occurs at an 18. h8kalgh ,0*p;b5 .ku)tqg dujkh2p2 s0$^{\circ}\,$ 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 diffractionez:ehao.8k4yl aq29 p:sx: kbju .kj 9 grating is observed atleaze 4.kk2byx:q 9::9 s oa8.upkjjh 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 has ujxm6 w70g ,zgfv2 5jg+utz,w $ 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 +cpfo6l)t 6s d3) im :du1iqsqa $9700-line/cm$ 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 gun +s3hjw f;(t7 ni(1 f*-bbmr8fqnozrating with 6000 lines per cm is illumib *83z fjtun7;(n qf(+f-bmh1wnsrionated with 633-nm laser light? Assume normal incidence.   

  Two (and only two) full spectral orders can be seen on either side o/ drfku-qahja,5 s,(s-i4vla -okz 0 mf the central maximum when whiteqjra5k- hovu-0k, sl zf ma(i as-/d,4 light is sent through a diffraction grating. What is the maximum number of lines per cm for the grating?    $ \times10^{ 3}\;lines/cm$

  White light containing wavelengths from 410 nm to 750 nm fnwu7p) 60on qnncc9* lalls on a grating with 0n*ccuwln7)q 6p 9nno $8500\;lines/cm$ 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 ,filj- .klp q*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 ;gtd ux)n:te6nes 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 wavelength-.u51to ;qd uqub w,u1yx(cg y is most strongly reflected at thecuu5uuq gy 1qbx-(yw ;t1. do, center of the outer 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 24–8 if the glass plates are eaoo9z hd:r/t-n ch 26.5 cm lo ot: h-zd/o9nrng?    cm

  What is the smallest thickness of a 70o wba)c/8sz cv 9ybgsoap 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 yellow (bkw (v:e,il xi eg h2me,o86d*$\lambda\;=\;570\;mm$ 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 sps ;h ,j)nt6qto6e;r /r *y9z) ljooorlot 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 cenoo o/j)h6e )n ;sl6,t9 lrzrt*yr; qojter than the edges?    $\mu m$

  A fine metal foil separates oo qwz6 t-3m2x*+iuj kkne end of two pieces of optically flat glass, as in Fig. 24–33.zk*6q2oi3u-tw+mk xj When light of wavelength 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 between -q 13zq)p0h4row9o ct gqnn m,two flat glass surfaces if the glass is to ap0hmrz q49ogn1q t-c,nwp3)oq pear 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 stolen3.;dqi6 zbscjhi qbr(a5 b) v-egb..n 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 alcoho:o wbpyres ,; 680bo,h0dhqkul $(n=1.36)$ 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 immk/ zs-0s8 zkd7 ai z8)hmvy7ezersed in a liquid, the diameter of the eighth dark ring decreases /y8h-vkme zs7iks8 zdz07) az 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 i-goiga0i e1;ol9 i hr.nterferometer if 644 bright fringes are1g9i o0ehg.i ai-rl;o counted when the movable mirror moves 0.225 mm?    nm

  A micrometer is connected to the movable mirror of an interferometer. When the mr1v8n qx57mpinu x4+micrometer is tightened down o41+xx pmrmi 5nvq n87un a thin metal foil, the net number 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 mirro6)g+yw l60bb)w y g,0dldnjt wr $M_1$ 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 intez uz5fuutb-(*1 z3bes rferometer (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 referb5b (e -3fz1*t uusuzzence 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 at oxe )f;(xs3hrfj0x k9 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 airbqzb 2 drn8 y6o1+oab:–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerged in water if the lcn(k lna9ciiej:/8rx(6 q6sl ight is hitting the diaml( /a6 8eqsi ri6(kj9ccnx: nlond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that tj ibh/un:a2,d/i5 (+ cbqs jhche light passing through them is a maximum. At what angle jb q 5+ chn:ids/abjh,(uic2/ 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 to reduce thc3:qbdm2 /c o. l0 a-icvah5)q1zz3kab(a htte intensity of the incident unpkvqcq(izbh-a.c3l /0m b hz1c ta5:ta23ao)dolarized light to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are orientee3f58i*r u;, f8ibtfaez( a ovd 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 af t7,4livr+i ot 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 of water for lig* ( shakscc us975kj q8)na7qdht coming from beneath the surface? Compare to thehs s7 cs)ac7n ua(qk59qkj8d* 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 success)1x hh+;ovady ive Polaroid sheets, each of whose axis makes a oxvh1;y+h)a d45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength vtuo noc* 6h :x1r0kg-$ 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 reflectingjm)lau37pg m td4f- g7 from mountains or airplanes can interfere with u af4-gm3 gt7ldm p7j)the 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 sepaiu*-pcc8 t * ym0ot 7iolw74ixrate sources passes through a diffraction grating with *cc l7m o* iui7t8-4yxto0piw$ 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 5bgnt6xo;n.5sb m7:g m 90 nm passes through two narrow slits 0.60 mm apart. The screen is 1.70 m away. A second source of unknown wavelength produces its second-order fringe 1.33 mm closer to tht;ns .76xgo:5gb bmmne central maximum than the 590-nm light. What is the wavelength of the unknown light? $\lambda_2$    nm

A radio station operating at 102.1 MHz broadcasts from two identica7+ir: ptlowo. l antennae at the soi:t+w7ol r.p ame 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 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 0.8 xlsgjix(.sm oz7u u7*.h1l8 f8 m wide, and blows a whistle of frequency 750 Hz. mluos.j u8lx. i( 71x*ghzsf7Ignoring reflections, estimate at what angle(s) it is not possible to hear the whistle clearly on the playground outside the doorway.    $^{\circ}\,$ either side of the normal.

If parallel light falls on a single slit uy ..qdievj7/ of width D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a series o1wf 2de4cv f2 /sf-da) +gt1e vzvoah t2zg36yf parallel lines across them. When normally incident 460-nm light is reflected from the wing1 zt+fydvhego2vvz24 a13f gt ) dcaf/2-swe 6, 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 gratin6vlnl7a-wu bxni,o6;kv-o ;gr , 1ryxg have if there is to be no second-order spectrum for avx6yxwkourg-,o7lr ;ib-6 a1 n, ;vnlny visible wavelength?   $ lines/cm$

Show that the second- and third-order spectra of whcwq y q4lhz28-ite light produced by a diffraction gr cwl8q- q2hy4zating always overlap. What wavelengths overlap exactly?

  When yellow sodium lightyr bvx.5p t;w r;wkm*x m,3/ik, $\lambda\;=\;$ 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 diffractl+zr2h) l( avlion grating with and the pattern is viewed on a screen 2.5 m from the grating. The incidev )lazll2hr(+ nt light beam consists 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 a m2.(tw-5r97zw az2x) wck wdnuq s zu(qinimum of 150 nm thickness of it, when laid on glass, is n2aq7(). 9wqwkduwt2cwz (-nsr 5 zzxueeded 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 4ido+ sn4(rhk variable wavelength is incident normally on a thin sheet of plastic film in air. The reflected light is r skho(d4+n4ia 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 thic,vt vv v7;vb8/- vggiokness needed for an 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 layernggz:d..m9 bc /vl9az between two flat glass surfaces if the glass is to appear dark when 640-nm light is incident normalndz:v/9glab gz. c9m. ly?    nm
What if the glass is to appear bright?    nm

Suppose you viewed the light transmitted through a thin film layered on ,a k3g,sreu7m6ux*nnf o ; (nsa flat piece of glass. Draw a diagram, 3,exr*no 6u(gk,;nnf m7susa 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 when light reflecting off a smo xoyzv9am0sft 7hj myi+7xq+w )(f6l9oth lake is polarized most stro9hxiwty 9mx +fy0(vlfsq6+o a77)j mzngly?    $^{\circ}\,$

  At what angle should the axes of two Po2zbl/8 q fdvxmwv6b-)laroids be placed so as to reduce the intensity of the incident unpolarized light by an ad6bb8qm)d /lx2zfv-v wditional 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 sheet, dotzbw pl4 l/uh5(: 6n4.do6g qwieus whose transmission axes are at right angles. A th,wwp5dbq4o led 6nuiog.6 ( h:ul4/tzird polarizer 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 axes vertical, 3k0 fsy yh3,tuat 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 slitu6ny0(xp0i plo8k*ca d t qra860.cuf of 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 0 6p*0kt6 .cu nyaxroq0dau (i8p8cflwidth of the beam when it reaches the Moon.    km

  A series of polarizers are ean;(w 4pwumu:5oohj.u- ffdy(ch 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 l5c ,bh/wi3d2 aczw p*$(n=1.34)$ 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.o igu9ea)i m8hz q5372o 4lnpu0-MHz radio waves in phase with each other. They aroqa2)3leozh4 m8n iui5p9u 7ge located at points $S_1$ and $S_2$, separated by a distance $d\;=\;175m$, Fig. 24–61. What are the first three points on the y axis where there will be destructive interference? (Destructive interference in this case means that a radio receiver placed at that point would pick up no signal).    m    m    m

  A parallel beam of light t/q6 qi7f,z3( ffba rtcontaining two wavelengths, 420 nm and 650 nm, enters a silicatqt aff,i76qbz( rf /3te 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 lens has one flat surface andc,n*cs-gj:kf5c g 7zg 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