Does Huygens’ principle apply to sound waves? To water waves? Expla qy v9gxcm3 rr7ly1(k;r51wu fin.

What is the evidence that light is enebmb2q ttjd68aqq 1zycq23g,4rgy?

Why is light sometimes described as r*hy4ge5kvsps pye796 ays and sometimes as waves?

We can hear sounds around corners, but we cannot see arw/j t jhr4y,l3ound corners; yet both sound and light are waves. Explain the d l twj4,3ryh/jifference.

If Young’s double-sli e0bw48q/jcjf iklf::2za 6j ht experiment were submerged in water, how would the fringe pattern iw0 l4qjzh2fjka/f b:c 6ej 8:be changed?

Monochromatic red ligeo zn bxqc( r60x,*t:hht is incident on a double slit, and the interference pattern is viewed on a screerh,o:t c6bzxn 0(x*qen some distance away. Explain how the fringe pattern would change if the red light source is replaced by a blue light source.

Two rays of light from the same source de+ ./i:t( ee 7refzhl: xt6cu/q+zflcqstructively interfere if their path lengths diffecxi+/qf fc . 6z:u /q etrlze(7hl:+etr by how much?

Why was the observation of the double-slit h* ojg lfm;nhjzm36) j10ue k;interference pattern more convincing evi3o el0 zg6j*um f1n;m;h)kh jjdence for the wave theory of light than the observation of diffraction?

Compare a double-slit experiment for sound 153h8lypezb) + ggkwtwaves to that for light waves. Discuss the similarities and diffwzg+e3bty8 ) 5lkg1hperences.

Why doesn’t the light from the two head s/9ud7chl .dtlights of a distant car produce an interference 7/uls9 ctd. hdpattern?

Suppose white light falls on3e-j5x2sm 1 2fx,: zejj gbwvo the two slits of Fig. 24–7, but one slit is covered by a red filter (700 nm) and the other by a bl- f2 v 2eb3,gjjwm5xo: 1xjezsue filter (450 nm). Describe the pattern on the screen.

When white light passes through a flat piece of window glass, it is notm lfq53,4q4pv3r 6umv9lus6 2qgz8 ktc/k onh broken down into colors as it is by a pris/f 6mqcu n hl6 vmqv4zkg 8kt3sr3,245oupq9 lm. Explain.

For both converging and diverging lenses, discuss how the fepa7j 3 ft;bbo f2ux hv19.;hvl xr91bocal length for red light differs from that for violet b 2j 31 vohu7;r x.ath9efflv9;1bxbplight.

A ray of light is refracted vdp6at s c./f hgpzc96:cz3)asgn/. v through three different materials (Fig. 24–55). Rank the materials according to their index of refraction, l6c )f nsvt9vhzsdp/6zp /.a3a :. cggceast to greatest.

Hold one hand close to your eye and focus on a distant ligha4rpm) s:*dkkke5t*jcs+* vdt source through a narrow slit bet d*kvp+d 5ck:am *stejrsk*4) ween two fingers. (Adjust your fingers to obtain the best pattern.) Describe the pattern that you see.

What happens to the difbj:1gl w z,r i-bfuoz6+3h6wg fraction pattern of a single slit if the whole apparatus is immersed in (a) water, (b) a vacuum, h,g6w16 ui3 olb+ f- j:zwgrbzinstead of in air.

For diffraction by a single slit, what is the effect of increasi wn+iw/sa26am, 6 qb/q(pdcoq ng (a) the slit width, and (b) the wam2q a+wqcd,sw/6pabq i /n6 o(velength?

What is the difference in the interference patterns formed (a) eiafe*m4hup; 2z))vh by 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) ma2bv (zu frm.(p5bk bx/ny slits, (b) closely s/fu5m (v.bbb xz(k2prpaced slits?

White light strikes (a) a diffraction grating, and (b)n / s,kgv26fjm a prism. A rainbow appears on a wall just below the direction of the horizontal incident beam in each case. What is the colo/6 mvsfnj2gk,r of the top of the rainbow in each case? Explain.

For light consisting of wavelengths betweef hlkx*))hv(i; p2mucby( q c-n 400 nm and 700 nm, incident normally on a diffraction grating, for what orders (if any) would there be overlap in the observed spectrum? Does your answer dependyi2(b (lc)xvqku)f h*;h pm-c on the slit spacing?

Why are interference fringes ne ud65v6b2 i siun1k+ff.x*q zoticeable only for a thin film like a soap bubble is* x venz2.fi6d6k5u1 +qufb and not for a thick piece of glass, say?

When a compact disk (CD) isp/dk/n3u9r/ vk3hepmhykh2sae l- 9: held at an angle in white light, the reflected light is a full spectrum (Fig. 24–56). Explain. k/39 yp hkmn/:v3dhu/-la rheskpe2 9What would you expect to see if monochromatic light was used?

Why are Newton’s rings (Fig. 24–31) closer together farther from the center? ca-v090mgr+/h:r * 9d he6mzx*z)lbj h gitiu

Some coated lenses appear greenishqhnuh* le26 e(d5(f5yokb q-w yellow when seen by reflected light. What wavelengths do you h eqe5kowl (n5hbqdy(fu2 - 6*suppose the coating is designed to transmit completely?

A drop of oil on a pond appears bright at its edges, where its thiqjf4xsp1 w3sz/ h7bg4ckness is much less than the wavelengths of visible light. What can yosbh13/swqgjp4 zxf7 4u say about the index of refraction of the oil?

What does polarization tell us about the,:s0fje u 1tq,pm 9*0snnt lej nature of light?

Explain the advantage of polarized sunglasses overq:e/hqbptf**rq4+bety4mp j 3 7n b6r normal tinted sunglasses.

How can you tell if a pair of sunglasses is poevcc1 0ltnbs 4d)9fc,z2i. ql larizing or not?

Two polarized sheetsj * ce*logh8.s rotated at an angle of 90$^{\circ}\,$ with respect to each other will not let any light through. Three polarized sheets, each rotated at an angle of 45$^{\circ}\,$ with respect to each other, will let some light through. What will happen to unpolarized light if you align four polarized sheets, each rotated at an angle of 30$^{\circ}\,$ with respect to the one in front of it?

What would be the color of the sky if the Earth had n/x8bum9ft g 4jo atmosphere?

If the Earth’s atmosphere were 50 times denser than it is, would sunlight stillh)53l fzd).vxpo rj2y be white, or woxf vp.2 hr )l3djzoy)5uld it be some other color?

  Monochromatic light falling on two slits 0.016 mm apart6 zeuc25)jy kq produces the fifth-order fringe uy6q2j c)z5keat an 8.8$^{\circ}\,$ angle. What is the wavelength of the light used?    $ \times10^{-7 }\;m$

  The third-order fringe of 610 nm light is observed at an angle .g8 ir*,,: vyda yx .r2ygtoiuof 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. Succe c :-l c:u+z buaznicd)-zz8z0ssive fringes on a screen 5.00 m away are 6.5 cm apauc:0z-z: l -8cbazinzz)d+ucrt 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,,30 t(e rcc25vwl9d1sxgjy i d falls on two very narrow slits 0.060 mm apart. How far apart are the fringes in the center of the pattern on a screen tj(sd5x, 2cl wrcvg y 0d139ei3.6 m away?    cm

  Light of wavelength 680 nm falls on two slits and produces an inur(fm.(wx s4y terference pattern in which the fourth-order fringe is 38 mm from the central fringe on a screen 2.0 m away. What is the separation (w(4yfums xr. of the two slits?    mm

  If 720-nm and 660-nm lighief*utmbs:-/qk3qd()-w3 r q gph: vdz6*sci t passes through two slits 0.58 mm apart, how far apart are the second-order fringes for t m*f- wd hzc kbit-/p:3)u(:3*gevqqiqds 6r shese two wavelengths on a screen 1.0 m away?    mm

  In a double-slit expkk; gx;p/:brd eriment, it is found that blue 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 p gkx ;;bk/r:dminimum at the same location?    nm

Water waves having parallel crestt ey: )- l1vgcpix.b k+xw4xkv5d2-ins 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-t 1wcv -5. y-eg)vt:bxx p2+dl4iixnk khrough” direction would there be little or no wave action?

Suppose a thin piece of glass is placed in front uy ucj6oh+q862pg 0e0okx6l u of the lower slit in Fig. 24–7 so that the two waves enter t+0qex 6u0kolju6yc 6 op gh2u8he 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 expe d)sn-l,a22k 9io6cf.q w 4mgv;w xlh- ndqfr5riment, the third-order maximum for light of wavelength 500 nm is located 12 mm from the central bright spot on a scrgl49f;,nqa.2 ohxnd f- wil qmk vc) wd5sr2-6een 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 second-order maximum of this light be located?    mm

  Two narrow slits separated by 1.0 mm are illuminated by 544 nm light. Find the fpk ufllb7x0sj:9t2796fyt+ p gl5 bs distancek5f0 sjy ls2x9l7flbu7+tb:ppt6fg9 between adjacent bright fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 nm in air fallvnc4u7yhp; -f s on two slits $6.00 \times10^{-2 }\;mm$ apart. The slits are immersed in water, as is a viewing screen 40.0 cm away. How far apart are the fringes on the screen?    mm

  A very thin sheet of plastic (n=1.60) covers one slit of ab(,zv co,ae sq83r(bsp6yz ar1yzt9: double-slit apparatus illuminated by 640-nm light. The center point on the screen, instead of being a maximum, iy, rqzav rs3z8cey(6 (aobp s,91zt:bs dark. What is the (minimum) thickness of the plastic?    nm

  By what percent, approximate pv qe0f sq8aya:70,jyfh2:iyly, does the speed of red light (700 nm) exceed that of violet light (400 nm) in silicate flint glas fea 8i0qa pqfj:02yyv:7, hsys? (See Fig. 24–14.)    %

  A light beam strikes a piece of kl6q 6+rxf /lco/am5 iglass 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 wavxjgw *; vu98qiyf k1*fnae +k2hs+un.elengths, $\lambda_1\;=\;450\;nm$ 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 v- .rh)y p(c1t g0ncaswide, what is the full angular width of theypacr1v c(h s )0ntg.- central diffraction peak?    $^{\circ}\,$

  Monochromatic light falls i;pwd5nc 9,0 .bfyhk, u)abph0f zj-eon 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 sa8) q0,la fffiuq9/nr2 z)zaslit 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 illuminaz1zyrz :+jlb /ted by 450-nm light. What is the width of the central maximum (in cm) in thezjz/+z:br 1y l diffraction pattern on a screen 5.0 m away?    cm

  Monochromatic light of wavelength 653 nm falls r* ba-6qxyj9g on a slit. If the angle between the first bright fringes on either side of tg -x9bj *qry6ahe 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 0yasimym ,3, 2t.0348-mm-wide slit illuminated by 589-nm lig2,i ya,m mys3tht?    cm

  When blue light of wavelength 440 nm falls on a single slit, wwr*0x9d)aa79 9icuy3 q ktp;h lf 7yithe first dark band;70 ua79tdwl 9fqcr)* 9wp i xy3iyhaks on either 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 7vpd k x+ez,0 h*5bwokon a single slit, it creates a central diffraction po*wkdz7px, + hev0kb5eak that is 9.20 cm wide on a screen that is 2.55 m away. How wide is the slit?    mm

  If a slit diffracts 650-nm yfrwq so p52ds2(yn ,kn:ms xgpc*9:-8atuu6 light so that the diffraction maximum is 4.0 cm wide on a screen 1.50 m aw2*sadus:5-fcsq ug nym,t ryp p:k2o6 x(8n9way, what will be the width of the diffraction maximum for light of wavelength 420 nm?    cm

For a given wavelength6y+gkq ;sju8b $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm light produc5,x+b (mp oy s6pe;aykvc7q 9ee a second-order maximum when falling on a grating whose slits areabp6qv7y59(eo pk,; x ye+ msc $1.45 \times10^{-3 }\;cm$ 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 do go5ts ur9: m u5mr2hsb3rjcg0,b:xp.es a grating have if the third-order occurs at an 1x,ocrg t:rb0:bmup9 uhs3sm25 rgj 5.8.0$^{\circ}\,$ 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 d-f ;y.px)ih 6x ( 1dbh*sng,pe ;gkmchiffraction grating is observed at akx g.chm;e6 hp-s,bg)xhn*1;ypdf( i 15.5$^{\circ}\,$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction gratink *r(8ua.qnfn g has $ 6.0\times10^{ 5}\;lines/m$. Find the angular spread in the second-order spectrum between red light of wavelength $ 7.0\times10^{-7 }\;m$ and blue light of wavelength $ 4.5\times10^{-7 }\;m$.    $^{\circ}\,$

  Light falling normally o:d7e b.k m9dkdkq 7;xhn 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 ori1l n)dff3+ zjder that can be seen if a grating with 6000 lines per cm is illuminated with 633-nm laser light? Assume normal incidenf+)n1 lz3d ijfce.   

  Two (and only two) full spectral orazd7 pb(9bj)h-2daz/t 3gs,i svh xy 6ders can be seen on either side of the central maximum when white light is sent through a diffraction grating. What is the maximum number of lines pe-)/j tpavshgy72bddz3,zhb s9 (ixa6 r cm for the grating?    $ \times10^{ 3}\;lines/cm$

  White light containing wavelengths from 5rev * ) s8qgf2ckzde7410 nm to 750 nm falls on a grating withdec 28*gr7)esq vfk z5 $8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which produces monochromatic lighti gpnhm)7v* 1q 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 spectrumt 7a+o mkkmy(: lines 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 is most strongly r 3zi01fl: a qtyx/fq:reflected at the center of the :lxq1q f/traif: zy30 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 Ext-d6:7 :n;m rlq)lr0posoz hgample 24–8 if the glass plates are each 26.5 nr:h0qm tgdlzl )p-:o 76;s orcm long?    cm

  What is the smallest thicknem 2nx:a0 py0wrss of 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. $t_min$    nm

  A lens appears greenish yellow ykce u mx. nyb(h0 9e1 mfp7i(cfg;/3e/(nwrk($\lambda\;=\;570\;mm$ 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 d7zw6ixh1(rdyhn2sve+1z 7 pg ark spot at the center) are observed when 550-nm light falls normally on a planoconvex lens resting on a flat glass surface (Fig. 24–31). How much thicker is the center than sy 7 6 px1zegv7w(i2dz1hrhn +the edges?    $\mu m$

  A fine metal foil separates onz4) 1eu3vdq dcc(eaw; e end of two pieces of optically flat glass, as in Fig. 24–33. When light of wavelength 670(zw 1ude)q3cc ;eva4d 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 thbg6mpj8w*9re 7 tzh (de air layer be between two flat glass surfaces if the glass is to appear bright when 450r9p67*zhbg md(wje8 t-nm light is incident normally?    nm
What if the glass is to appear dark?    nm

  vA piece of material, suspected of be69 lga ao wm+laa+r/3zing 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 alcohh3zp7s wr-q4g -,0o:z fvpr avol $(n=1.36)$ 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 (pt29q g y0mk9bFig. 24–31) is immersed in a liquid, the diameter of the eighth dark ring decreases from 2.92 cm to 2.48 cm. What is the ry09 gm9t k2qbpefractive index of the liquid?   

  What is the wavelength of the light eo(wd ) e1 (mue)1kpu pv04ocem5dva)fntering an interferometer if 644 bright fringes are counted when thv )dae1vwdep1)fm50)p(emcu(o uo4ke movable mirror moves 0.225 mm?    nm

  A micrometer is connected to the movable mirror of an interferometer. Wheto ( 4mbwtj0fph:v5;sn the micrometer is tightened down on a thin metal foil, th0wjtp o;4btfm(vs :5h e 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 mirronb- r7f5x 7n*;c(u7ujp te sbdr $M_1$ 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–dbx *x8,fl;bt 59) passes through a small glass container containing a cavity 1.30 cm deep. When a gas is allowed *d8fxl x,t;bb to slowly fill the container, a total of 236 dark fringes are counted to move past a reference line. The light used has a wavelength of 610 nm. Calculate the index of refraction of the gas, assuming that the interferometer is in vacuum. $n_{gas}$

  

  Two polarizers are orientv a;tk4 ,bxpg4ed 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 4b7eny 6ds 9(ajm8zqc/ a*ujc an air–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerged in water7o ksot dqki0 k/w6)szis( 145rqdux+ if the light is hitting ti5d+)dk ts60xq k(q u/oi rs4s wo1zk7he diamond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are alignpi0*rf,fpqio - 0upwp )h5pc8 ed so that the light passing through them is a maximum. At what angle should one of them be placed so th0upopcp5h,8i -0iw *pq) f fprat the intensity is subsequently reduced by half?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so as to reduce the iva/v0i wrc9 jgx n)9qq 2s0ez)ntensity of the incident unpolarized x0i92 )0zgvq)c9snjrveaw / qlight to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oayma36*ei av(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 orientedew- opoyu )m0psq,+j til ;r*) 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 the surface of water for fwq d n.(*umf i87xrcz2f)ty5light coming from beneath the surface? Compare to the angle for total internal reflection, and to Brewster’s angle from above the *r m)tqd n5w 8.iuf(2xzff7ycsurface.
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 Polaro.d)8vqz iq0v mrm z.s)id sheets, each of whose axis makes a 450vq.rm8)z .vzqsimd )$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength */ aia(ctpl8s ea/y03q r/kd c$ 5.0\times10^{7 }\;m$ passes through two parallel slits and falls on a screen 4.0 m away. Adjacent bright bands of the interference pattern are 2.0 cm apart.
(a) Find the distance between the slits.    mm
(b) The same two slits are next illuminated by light of a different wavelength, and the fifth-order minimum for this light occurs at the same point on the screen as the fourth-order minimum for the previous light. What is the wavelength of the second source of light? $\lambda_2$    $ \times10^{-7 }\;m$

  Television and radio waves reflecting from mountw;m;qo r , 6 :rb/xyssv4sj8 akfohsm-2j9u5nains or airplanes can interfere with the direct signal from thejsjsh8q ;:k/fv,6rxo r5m4 29 s mob-yusn;aw 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 soncb w7ymz(+9tt a7 rfnfz*09vurces passes through a diffraction grating with y+wmb ztcazt70 f799rnnfv* ($ 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 z 7 x0(olwj2 m3aqcs(vnm passes through two narrow slits 0.60 mm apart. The screen is 1.72 (s( 7j0lz ova3wxmcq0 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 light. What is the wavelength of the unknown light? $\lambda_2$    nm

A radio station operating at 102.1 l b2w,*nnkbm0xh/4 0fca.bne MHz broadcasts from two identical antennae at the same elevation but separated by an 8.0-m horizonta4knebbl mxa0.2 f,ch n*0nwb /l 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 0.88 mu jbwl* n9ig) (yip4d8 wide, and blows a whistle of frequency 750 Hz. Ignoring reflections, estimate at what angle(s) it is not possible to hear t9jn (wpb di)g48iy*u lhe whistle clearly on the playground outside the doorway.    $^{\circ}\,$ either side of the normal.

If parallel light falls on a single slit of width Df) ,;z; nz52f2qfvh0zc kbkyw at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a serij4yh (u wf;d5ies of parallel lines across them. When normally incident 460-nm lighujy5i 4(w;d hft is reflected from the wing, the wing appears bright when viewed at an angle of 51$^{\circ}\,$. How far apart are the lines?    nm

  How many lines per centimeter murd4ol-g)y1pd st a grating have if there is to be no second-order spectrum for any vis1 pd )drg-4oylible wavelength?   $ lines/cm$

Show that the second- and third-order spectra of white light produced bc-lxp((a 7yn23m a zvcy a diffraction grating always overlap. What wavelengths overzv n2 x m-7yc3(a(aplclap exactly?

  When yellow sodium ligh lm/h/ ozrtg;o4f ./59mtfzmpt, $\lambda\;=\;$ 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 gr*e,ni,0c .tpny7 xarlating with and the pattern is viewed on a screen 2.5 m from tr* etn ,p7c,iyln.0xahe grating. The incident 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 c5qq) 4l juk3+yry;( vuwg b/qof a clear material if a minimum of 150 nm thickness of it, when laid on glass, is needed to reduce reflection to nearly zero when light of 600 nm is incident normally upon it? Do you hc ;ygb(5wquvkq)3 r/qy4+ljuave a choice for an answer?

  Monochromatic light of variabl9izx9qky*.o5o+ bu- upf2w g ze wavelength is incident normally on a thin sheet of plastic film in air. The refi f x uwzob9-po2z*qg9u.5k+ylected 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 ne)h r.bqr*p2f*byj3wu eded 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 u. zg2pig:2 +2en)u)y t *jxi b7kdajnfor the air layer between two flat glass surfaces if the gla j)ib27 2unk jn:ze d2+.ip)ugayx*tgss is to appear dark when 640-nm light is incident normally?    nm
What if the glass is to appear bright?    nm

Suppose you viewed the light transmitte0en)vfe+tngd6fyf5 f;3il q/d through a thin film layered on a flat piece of glass. Draw a dii0 g5en)v n6f qfdey+ft3fl/;agram, 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 Sul2dwi+-it95c8 b )n1xvmr j gen when light reflecting off a smooth lake is polarized9c21bv8w j+ ntxdigem)i l -r5 most strongly?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so as to red-m6fff qs*eooebwlc7nf ) g)31 w yb.8uce the intensity of the incident unpolarized light by an additione yfwf.- 8* gnfwsbf))3 qomcel167obal factor (after the first Polaroid cuts it in half) of
(a) 4,    $^{\circ}\,$
(b) 10,    $^{\circ}\,$
(c) 100?    $^{\circ}\,$

  Unpolarized light falls on two pokqo7*oqif2m)cvi1cvbb / 5 ;j larizer sheets whose transmission axes are at right angles. A third polari5o *vj 7i/f1 c2bvi;bqq)mo ckzer 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 5nujvwn r* g:5izbgk9- ornbuo;2( 6rin succession 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 t7jct:pqz0f- ttj 2( za slit 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 las(tz 20:jtt-qcjf t7zp er). Estimate the width of the beam when it reaches the Moon.    km

  A series of polarizers are each plaz5c 7aytl67i eced 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 l2we/*cf.8bkh ko p1z$(n=1.34)$ 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 v8wj ( sqgfh-*in phase with each other. They are located at pointsjg(*w-s8hfv q $S_1$ 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, enmw hnwyw2+) :10ccmqvters a silicate flint glass equilateral prism (Fig. 2:q )0y2c+m hww mcwn1v4–58).
(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 and.s4*z3jyuc19pc uj ic 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