Does Huygens’ principle apply to sound waves? To wat/ s3xsf* ;yac ne2x 0u4(pvscver waves? Explain.

What is the evidence that lf, *e7(kv4c5vint kbe b(nf b8ight is energy?

Why is light sometimes described as rays and sfr*0 (7jphryc2)sgk c ometimes as waves?

We can hear sounds around corne+;(ghlm f yq2jqdt q+b-3havhq3ey97rs, but we cannot see around corners; yet both sound and light are w9vdej+h3;q-3+glfyqhqb myq72 ta (h aves. Explain the difference.

If Young’s double-slit experimw,ov- se/2hw q4ug7d ient were submerged in water, how would the fringe patuqg,wv7 s 2e /4hoidw-tern be changed?

Monochromatic red light is incident onffyohb 8 4j5hkaaz5,lqy8r :0 a double slit, and the interference pattern is viewed on a screen some distance away.hk af5ro5 zyh:f q08a,lyjb84 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 thexu;6bqbzsb,s.f 2k-) b: w.0 ym 76honeeevkgir path lengths dn6zbxs7e o)kbbb vg-u..kqf:h2m6y e;, e 0wsiffer by how much?

Why was the observatiofu9-7ut/w k-z uq1sae n of the double-slit interference pattern more convincing evidence for the wave tuu-z e9qfkw 7t/1- asuheory of light than the observation of diffraction?

Compare a double-slit experiment for sound waves to that for light wav ac10.-xcw+osxm f +ti+u.uuves. Discuss the simi+.uco+it1w+ mu.xvu- 0as cxflarities and differences.

Why doesn’t the light from the two headlights ofnznaa e1 *oyvq0ie9.0 a distant car produce an interference pat0qvn* yn9ae1.ieza 0o tern?

Suppose white light falls on the t0 yhs q0 :pvil 2e-ksb,eybk59wo slits 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 the pay0:hyivkeb p 2e,0qklbs9 -s5ttern on the screen.

When white light passes through a flat piece of window glass, it is not brokhylt-syg9 0w)/6e qka1c-g .wv3wypeuup f, 5 en down into coe0-cs1.wy6/ g kwp tg-yha)yl up,ue5 9 vf3qwlors as it is by a prism. Explain.

For both converging and diverging 48diocify 5r;l28.s0x tfai z lenses, discuss how the focal length for red light diffr .4s ic2o8ix8af0f z5l d;tiyers from that for violet light.

A ray of light is refracs- q1j6nly ;s /r7jjpjted through three different materials (Fig. 24–55). Rank the materialsj; qpjns7rjly 61-/sj according to their index of refraction, least to greatest.

Hold one hand close to your eye and focus on a distant light soupvi)t8zz*1dr/v0h8fhvz(3z fzo rs2 rce through a narrow slit between two fingers. (Adjust your fingers to obtain the)do0vz8z8(t1vh r/h f*i pvz3 sz2fr z best pattern.) Describe the pattern that you see.

What happens to the enlz ,t03av.d;kx: 9n rljai5 diffraction pattern of a single slit if the whole apparatus is immersed in (a) water, (b) a vacuum, insteadd5n9x nez0;tlk ar,a3 v:l. ij of in air.

For diffraction by a single slit, what is the effect ,j6 puncp2 t1:(4dwvw :0 gclfnuhwo; of increasing (a) the slit width, and (b) the wavele w4 l6tju(ow2:huwcngp c10p v,f :d;nngth?

What is the difference in the interference patterns formed (a) by two s(pc+/zgck;2hr r2u mv lits ${}^{-4}c{m}^2$ apart, (b) by a diffraction grating containing ${10}^{4}lines/cm$?

For a diffraction grating, what is the advantage of (a) ma;xrcb)lc / zc6ny slits, (b) closely spxb; crclz/6)caced slits?

White light strikes (a) a diffraction grating, and (b) .w2 o7d5cv tpwa prism. A rainbow appears on a wall just below the direction of the horizont v5wdwpt.c2o 7al 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 a, g p2ixr,q) 1nk+tp4*ismio l7kmx6normally on a diffraction grating, for what orders (if any) would there be overlap in the observed spectrum? Does your answer depend on the sli*+2ig x,n14opliix7)arm q6p ,tskkmt spacing?

Why are interference fringes noticeable only for a thigvorph*p46a wzgq v- -qr w4c/r4i77t) eeto)n film like a soap bubble ang o a)7z4rqvi/-hg) e6-q4t owr v*pe74tw rcpd not for a thick piece of glass, say?

When a compact disk (CD) is held at an angle in white light, the reflectefhq)uvx -(/j,v*.vrqmq 8,ne5lklor d light is a fv-x, n. e5 m/qr,* kvhqjv8lou)( flrqull spectrum (Fig. 24–56). Explain. What would you expect to see if monochromatic light was used?

Why are Newton’s rings (Fig. 24–31)jm 40pv0fw*5)0nr 1 *ygoloe ep4dnkr closer together farther from the center?

Some coated lenses appear greenish yelwzf xu77z5c, a-nye9q 1idat .low when seen by reflected light. What wavelengths do you suppose the coating is designed to transmit completelyy 1 7f.adcq 5wzi,ue-xnt97az?

A drop of oil on a pond appears bright at its edgu *9 a(u4ezrekou1:h.k twpm ,es, where its thickness is much less than the wavelengths of visible light. What can you say about th eeo,14 *9t.ahkwm:u pukrz(ue index of refraction of the oil?

What does polarization tell us about the nature of li82mh y8hisn v9ght?

Explain the advantage of polarized sunglas98le x3aj/nori xf568 uwjz8f ses over normal tinted sunglasses.

How can you tell if a a1fh -uqu:zdu*pd 5460ljfa spair of sunglasses is polarizing or not?

Two polarized sheets -8q:b xgl w(pfg 6ztf7rotated 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 tg ;19ribge -hkhe Earth had no atmosphere?

If the Earth’s atmosphere were 50 times densj (h,ip1 ch5*jmwvdclzj 0 6h1er than it is, would sunlight still be whitec51 ( ph6iv0l,1 djmjwj zch*h, or would it be some other color?

  Monochromatic light falling on two slits 0.016 mm apart pwi;5hxh 5ps43fow sx81m 6y karoduces the fifth-orderw1 x;sf3my8 ih45 5xoahpk6 sw fringe at an 8.8${}^{\circ }$ angle. What is the wavelength of the light used?    $\times {10}^{-7}m$

  The third-order fringe of 610 nm light is oise 9ofz/w ip533,lgc4n r xk54dt8d lbserved 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 twovo9 v)-.wt/lnqb uhi ( very narrow slits 0.048 mm apart. Successive fritbuvvlwn)/oh- 9i.q (nges on a screen 5.00 m away are 6.5 cm apart near the center of the pattern. Determine the wavelength and frequency of the light.
$\lambda =$    $m$
$f$ =    Hz

  A parallel beam of light from a He-Ne laser, with a wavelength 656 nm,ssrsc-d * ,alfog+d5 4 falls on tw-l,+ds4s*fco g5a r dso 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?    cm

  Light of wavelength 680 nm falls o-5nu q/nm 0o4ox6rm+as hn0ub n two slits and produces an interference pattern 0ub4m6o/ uh+smaoqx-n0rn5nin which the fourth-order fringe is 38 mm from the central fringe on a 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 ae2-frgroh knm5 fn56:o3)c qcpart, how far apart are the second-order fringes for these two wavelengths on a screen 1.0 m a-3 :)cc26nr ormfh okg fqn55eway?    mm

  In a double-slit experiment, it is found that bluh9) cu;*r zouu ub2a9ze light of wavelength 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 same location? )u*; uuh29bozza9ur c   nm

Water waves having paralleld 1mf9 per2;6hpgoj;u jw l3;l crests 2.5 cm apart pass through two openings 5.0 cm apart in a board. At a point 2.0 m be f19r2we;lj;;h d3lp6umo g jpyond 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. 24+1mpxdvu x 9)g5xeg/a 5.lbcq–7 so that the two waves lg95gm1 .b) upae+5xcd/xqxv 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 forhodk rp byqi z6:z0)75 light of wavelength 500 nm is located 12 mm from the central bright spot on a screen 1.6 m from the slits. Light of wavelength 650 nm is then projected through the same slits. qzdyb6 7 )p ikzor0:h5How 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 544 nm light. Find f; ro6p grxcu1;f(k* bthe distance between adjacent bright fringes on a screen 5.0 m from the slits. rgxfu(fkb1; 6p;c* ro   mm

  Light of wavelength 480 nm in aiq a+ s6wd.o-2/ev c ga*yojn.er falls on two slits $6.00\times {10}^{-2}mm$ 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= 77x6b lq+sns,gjn9 uh1.60) covers one slit of a double-slit apparatus illuminated by 640-nm light. The center point on the screen, inste +q,7xbsjusl 6hg97 nnad of being a maximum, is dark. What is the (minimum) thickness of the plastic?    nm

  By what percent, approximately, does the speed of red lbc ;52y lb.bt/z5rfejight (700 nm) exceed that of violet light (400 nm) in silicate flint glass? (See Fig. y 2rczj.;b55/bftebl 24–14.)    %

  A light beam strikes a picl;q:3ixm. 3v8v uuekece 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 contains g(g;y ehi)8cing two wavelengths, ${\lambda }_1=450nm$ and ${\lambda }_2=650nm$, 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 29ywcnkcxls 1 gll*/uu+ml.,eong wv 843u; aa slit 0.0440 mm wide, what is the full angular width of the cwl ov 3*4gwc /;gu aenmsl ,ull19nxk.82cu+yentral diffraction peak?    ${}^{\circ }$

  Monochromatic light fallb i+cy/pt r*q* k ysx+r*5x9fzs on a slit that is $2.60\times {10}^{-3}mm$ 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 fallr;ih p:rb6 / avkldp80s on a slit that is $3.20\times {10}^{-3}mm$ 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.cl6zg twv4jlzq-cn q2e(-w2)3hdulb 7h 1a d by 450-nm light. What is the width of the central maximum (in cm) in the diffraction pattern 2vzhae6jdb2cwzl lqd17 qulgw 4-.n-ct)h(3 on a screen 5.0 m away?    cm

  Monochromatic light of wavelength 653 nlhacyxt cpn *:9)n ,p;m falls on a slit. If the angle between the first bn)thcnpl,xa9* : py;cright fringes 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 mra3ztuhmavr9d /t2 )ui x0*+ v behind a 0.0348-mm-wide slitr9+aa0dzm v/vx3rut)t iu* 2h illuminated by 589-nm light?    cm

  When blue light of wavelei:/ y;tx0 ,ltvqmn6 wgngth 440 nm falls on a single slit, the first dark bands on either side of center are separated by 5x/ q:; ygvl0t,mi wt6n5.0${}^{\circ }$. Determine the width of the slit.    $\times {10}^{-7}m$

  When violet light of wavelength 415 nm falls on a single slit, itwns8gny2 ipx3z4s- g2 creates a central diffraction peak that is 9.20 cm wide on a scrg2-s xsywnnig3 p2z84een 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 cmx.zr/g y1-,ah,i tt*h) s( vyr6x ymxm wide on a screen 1.50 m away, what will be the width of the diffraction maximum for light of wxz *yvhxr6ty -m1y xir,ah/s,. t (m)gavelength 420 nm?    cm

For a given wavelengtr9ubw2wmkbm:sd, wm2bx+f0 9 h $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm light l1/ok1xzk.zjb8 5g lfproduce a second-order maximum when falling on a grating whose slits are/1x g.f 8kz1bzlol j5k $1.45\times {10}^{-3}cm$ 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 thiau0 -6us0gn dgrd-order occurs at an 06n d -ggsuu0a18.0${}^{\circ }$ angle for 630-nm light?    $\times {10}^{3}lines/cm$

  A grating has $8300lines/cm$. 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 grating is obs:iuhfdkm: 9iv1i6pk; erved fk:umipi k69d;hiv1 : at a 15.5${}^{\circ }$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction grating he,ai08(.7don z 3 l xx3hoqfkmas $6.0\times {10}^{5}lines/m$. Find the angular spread in the second-order spectrum between red light of wavelength $7.0\times {10}^{-7}m$ and blue light of wavelength $4.5\times {10}^{-7}m$.    ${}^{\circ }$

  Light falling normally o ;gpzm g0n,3gxn 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 that can be )-s erebqfo) +2 4jrqu7eho2p yx 4d7iseen if a grating with 6000 lines per cm is illuminated with 633-nm laser light? d )fy7)ei2q+ereq 4 uo7-xo24sbhjp r Assume normal incidence.   

  Two (and only two) full spectral orders can be seen pptw v9.0)mwrn-2r up on either side of the central maximum when white light is sent through a diffraction grating. What is the maximum number of m 0)v-p nrr.pwp92twulines per cm for the grating?    $\times {10}^{3}lines/cm$

  White light containing wavelengths from 410 nm to 750 nmi uagf8+wh; n7( h.moo falls on a grating with ;.fgw+h8homn a( uo7i$8500lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which produc+p djri6k5l- l6- kh4cjkx.kies monochromatic light of a known wavelength $\lambda =6.328\times {10}^{-7}m$ 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?    $\times {10}^{5}lines/m$

  Two first-order spectrum liner*0*woy, *+jmia 2ft q/yeydo s 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 wavelenij i6carve,95 1+omqq gth is most strongly reflected at the center of the outer surface when illuminated normally by white light? Assume tv,1r 9q qca5jo6meii+ hat $n=1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringes in Example 24–8 if tzb7i d/zj;dh1 he glass plates are each 26.5 cm long? dd bhzi17; /zj   cm

  What is the smallest thickness ofar tp i.,3pcd1 a soap film $(n=1.42)$ that would appear black if illuminated with 480-nm light? Assume there is air on both sides of the soap film. $t_{m}in$    nm

  A lens appears greenish yl+k :oqk2v +vkellow ($\lambda =570mm$ 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 Newwy-u l(lo. kc0ton’s rings (not counting the dark spot at the center) are observed when 5ckyo(w .- ull050-nm light falls 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 o d,1* qkl ,;dlnz1lffkh:uie2f two pieces of optically flat glass, as in Fig. 24–33. When light of wavelength 670 nm is incident normally, 28 dark lines are observed (with one at each 1,ulf ekl2i dhd k:q ,;*z1nflend). How thick is the foil?    $\mu m$

  How thick (minimum) uiv z j c(v2xys32rk)(h(/ iudshould the air layer be between two flat glass surfaces if the glass is to appear bright when 450-nm light is incide hv3kcixs(zv2()rd j2(i uu/ynt normally?    nm
What if the glass is to appear dark?    nm

  vA piece of material, suspea3dz7u:m yx x5ezz22 *a;lmb scted 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 alcohe5:sdv g-xw-k radem.mvb2-8ecr j-2ol $(n=1.36)$ 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 $\lambda =512nm$ and a maximum for $\lambda =640nm$ What is the minimum thickness of the film?    nm

  When a Newton’s ring apparatus (Fig. 24–31) is immersed in a liquid, tq cp:q9e9st r6he diameter of the eighth dark ring decreases from 2.92 cm to 2.48 cm. What is t c6rq9s te9:pqhe refractive index of the liquid?   

  What is the wavelength of the light entering av,t8r jguud *k-j 1)wzi4l;h zn interferometer if 644 bright frinh1,gz8 irluvj tu- 4j)z*k;w dges are counted when the movable mirror moves 0.225 mm?    nm

  A micrometer is connected to the movable mirror of an interferometer. Whx:i3d,l-tmg p en the micrometer is tidgl m, pit:3x-ghtened 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 of the foil? The wavelength of light used is 589 nm.    $\mu m$

  How far must the mirro ;1bu9*8jmatrb t9mbp p+6zk 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 interferometer (Fig. 24–59) passus6w ht0zgvqc6 p u0w.7 ok69les through a small glass container containing a cavity 1.30 cm deep. When a gas is allowed to slowly fi0k6.w9otwqu7cl u6s zp 0vh6g ll the container, a total of 236 dark fringes are counted to move past a reference line. The light used has a wavelength of 610 nm. Calculate the index of refraction of the gas, assuming that the interferometer is in vacuum. $n_{gas}$

  

  Two polarizers are ofrvip f9;2b5.skfzd jcu9m,. riented at 65${}^{\circ }$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s angle for 0pj b,vuu0zq ;y,hz)v7e-zoqan air–glass $(n=1.52)$ surface? ${\theta }_p$    ${}^{\circ }$

  What is Brewster’s angle for a r 52f9i3v uhvv 4ln6z.8digaldiamond submerged in water if the light is hitting ti hv2u.ng l 4a93vr5dvf6 8lizhe diamond $(n=2.42)$ while traveling in the water? ${\theta }_p$    ${}^{\circ }$

  Two Polaroids are aligned so that the light passing through them is a maxi9xt4 )y .vt*oajp d3inf2y q,jmum. At what angle should one of them be placed so that the intensity is sjpi, .q 4yx)2n *dy9at3tfvj oubsequently reduced by half?    ${}^{\circ }$

  At what angle should the axes of two Polaroids b)ilgtgrf1 n3 *e placed so as to reduce the intensity of the incident unpolarized lig 3ftil1ngr)g* ht to
(a) $\frac{1}{3}$ ,    ${}^{\circ }$
(b) $\frac{1}{10}$ ?    ${}^{\circ }$

  Two polarizers are oriented at 4-3lh)rd lsvi-ba6 d 5l0${}^{\circ }$ 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 rb eak7*-w*or 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 an mf8.gy9yad/gqv g(qpkq+8c 4gle be for reflections off the surface of water for light coming from beneath the surface? /.kg9g8q4+pgafcqy8yqmv d( 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 ${\theta }_p^{\prime }$   ${}^{\circ }$

  Unpolarized light passes through five successive Polaroioz9+xulf -j 0wd sheets, each of whose axis mu+lj90 -fo zwxakes a 45${}^{\circ }$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength hp+ki+-i3tzt pzv0.lv p - rz9$5.0\times {10}^{7}m$ 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? ${\lambda }_2$    $\times {10}^{-7}m$

  Television and radio waves reflecting from mountains or airplaneupga q-m1) omd0tto 8/s can interfere with the direct signau-qp) /t g0d1m amt8ool 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 diffraction gf:j q797b8c*s+ 9:iajer lbtvm g7p iwrating with qfjpegm 9 b8 ab+s7:rti*w :v7lc9ij7$3.00\times {10}^{5}lines/m.$ The wavelengths of the three lines are $6.56\times {10}^{-7}m$ (hydrogen), $6.50\times {10}^{-7}m$ (neon), and $6.97\times {10}^{-7}m$ (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 apard)uq42 ifwbg(vw u 5p3t. 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 maximum than the 590-nm 5vd 2upbui)qfgw (w3 4light. What is the wavelength of the unknown light? ${\lambda }_2$    nm

A radio station operating at 102.1 w)h5mqxv oo7n6wtyk(58 kl9j MHz broadcasts from two identical antennae at the same elevation but separated by an 8.0-m horizontal distance d, Fig. 24–qhkw( ym kt o76958xn5owlv)j60. 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 agmwdkbgp+8 :a :3x8 vmn outside doorway 0.88 m wide, and blows a whistle of frequency 750m: wdg3p + kbm8v:ag8x 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 wuzbx*3 u n+h6elnuy11s, ti( 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 serh.8l/ q4 9a 26 rim4jou+mnq.u3kjedyh cmvr5ies of parallel lines across them. When normally incident 460-nm light is ref.64 mr5mqhai+ 9vuo nmkrq u8l ech 34.jyd/2jlected 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 gratix7 jdq+e,u2 xmng have if there is to be no second-ordej, q7 e+2muxdxr spectrum for any visible wavelength?   $lines/cm$

Show that the second- and third-order spectra of white light produced by a diffrq 5e,jk9vmq,k action gr5mekkjvq, q ,9ating always overlap. What wavelengths overlap exactly?

  When yellow sodium liz g9bxceeh/ (c/.h- xjght, $\lambda =$ 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 withql/x 4*unx(yw and the pattern is viewed on a screen 2.5 m from the grating. The incident light beam cons (qxu4xy/lw* nists of two wavelengths, ${\lambda }_1=4.6\times {10}^{-7}m$ and ${\lambda }_2=6.5\times {10}^{-7}m$. Calculate the linear distance between the first-order bright fringes of these two wavelengths on the screen.    m