Does Huygens’ principle apply to soundr9wsc19- :o -kmtc omh waves? To water waves? Explain.

What is the evidence that light is en 8/zuodtn gxfsb4f.9/ ergy?

Why is light sometimes described as rays and some(+b 0)nbbg a+dmi/t vdtimes as waves?

We can hear sounds around corners, but we cannotgd02hi co:o zaq0/9 qk(yp2a l see around corners; yet both sound and light are waves. Explain tqp2dy oa(02aokiz9g hq/ c0:l he difference.

If Young’s double-slit experiment kb-e s(k-9w e egb(ka-were submerged in water, how would the fringe pattern(-beke(eba- k s9k-wg be changed?

Monochromatic red light is incident on a double slit, and w5g*ctx h1ck 2q/y7wpthe interference pattern is viewed on a screen some distance away. Explain how the fringeww72g ccqxh* 5pt1y/ k pattern would change if the red light source is replaced by a blue light source.

Two rays of light from the same source destructively inteawz ,u;h/ by q;5a r.tspoi7:qct(gz. rfere if their path lengths differ bt;5z.ha . ,su7bp q;yzqr( t/iw:gc oay how much?

Why was the observation am- f d uqrt+qf5 8w:lj))9a2pnvrt.kof the double-slit interference pattern more convincing evidence f-+a rtf ftdqq5 lm)up8:n9 rw j2ka).vor the wave theory of light than the observation of diffraction?

Compare a double-slit experiment for sound waves to that for light waves8lbfpbw*dv;j *h xm8+. Discuss thehbw fx;8j d*p8m vb*+l similarities and differences.

Why doesn’t the light from the two headlight e3ym:,xy jh4as of a distant car produce an interference e 3 j:4xa,yymhpattern?

Suppose white light falls on the two sliwu):,: ttwjdsts of Fig. 24–7, but one slit is covered by a red filter (700 nm) wtd,u s: t)wj: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 glklnvu)9 fyw-g46t1v a ass, it is not broken down into colors as it is by a prism. Expllk9wgty6v - 1uv 4f)anain.

For both converging and diverging lenlwvz s e44*b rgg+1j9+,y ra q)f9thnbses, discuss how the focal length for red litarv 9 *gwh4s1 j+)yf, +rgnb9eq4zblght differs from that for violet light.

A ray of light is refracted through 0lnnb r9(5 iajthree different materials (Fig. 24–55). Rank the materials according to their index of refraction, leas( jil0n9a r5nbt to greatest.

Hold one hand close to your eye an)lg7p0h+gh s2nqu r26 zt 3rfsclk14od focus on a distant light source through a narrow slit between two fingers. (Adjust your6khr gu1g7zos2pllf4n)02 rs 3tc q+ h fingers to obtain the best pattern.) Describe the pattern that you see.

What happens to the diffraction pattern of a single slit if the wholey. v3jt8xo .4 zcw3,kdz +g:rlaebu,u apparatus is immersed in (a) water, (b) a vacuum, instead , jzxz: .a+ g3tbek4ovu3y 8.lc,urwd of in air.

For diffraction by a single slit, what is the effect waj zt+qn,ejvs( 8lb*k0 w8/f of increasing (a) the slit width, and (b (q bn8lzwet8vsj0 /* a,fwkj+) the wavelength?

What is the difference in the interference patterns formed (a) ba *,:evi ndwq+ yn5cw;y two slits $^{-4}\;cm^2$ apart, (b) by a diffraction grating containing $10^4lines/cm$?

For a diffraction gratinge2olu4usn)8i 2rv.jx)c8q4 ur kt5 ma, what is the advantage of (a) many slits, (b) closely spaced su4 8k2qse )24cxrv.5mnt ou iu) a8rljlits?

White light strikes (a) a diffractionog t3 xdxf4* /ymddh61 grating, and (b) a prism. A rainbow appears on a wall just below the direction of the horizontal incident beam in xd/yt6dxm31 hd go 4f*each case. What is the color of the top of the rainbow in each case? Explain.

For light consisting of wavelengths between 400 q mqkd8ov+4;5di5( *eorz tbtnm and 700 nm, incident normally on a diffraction grating, ;b ddooz 5mk qtvi*5e+t8r (4qfor what orders (if any) would there be overlap in the observed spectrum? Does your answer depend on the slit spacing?

Why are interference fringes n:gsk 6 vcqd05boticeable only for a thin film like a soap bubble and not fb5:6 cq dk0gvsor a thick piece of glass, say?

When a compact disk (CD) is held at(kczxo4:/xi nk w s,-w an angle in white light, the reflected light is a full spectrum (Fig. 24–56). Explain. What woulxiw 4 -xcn w/zsk,:o(kd you expect to see if monochromatic light was used?

Why are Newton’s rings (Fig. 24–*3 k(uqkdw po/3h 2nys31) closer together farther from the center?

Some coated lenses appear gl0i 5;9u(rmkp kt 1ljpreenish yellow when seen by reflected light. What wavelengths do you suppose thkup1t9mk0 ;jr(5 lpil e coating is designed to transmit completely?

A drop of oil on a pond appears bright at its edges, where:5jae zd qdok5w5: 7pp its thickness is much less than the wavelengths of visi:7zq: 5dw5ao5p pekdj ble light. What can you say about the index of refraction of the oil?

What does polarization tell us about the nature of light?lf-gcoqi x7 ( zokl:.2

Explain the advantage of polarizedsz8avdu0o++kcgt.8 u hhx-(h sunglasses over normal tinted sunglasses.

How can you tell if a pair of sunglasses is polarizi5uekatgd psau,/q4l61r( 2 oing or not?

Two polarized sheets rotated at an ocr+yv,-hx8 l3nov.5ppaj 2 cbg1) uu 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 no atm5 s kzv7f 74x vdc6mp1helq49csf8lb7osphere?

If the Earth’s atmosphere were 50 times djuutm1 .b, j4censer than it is, would sunlight still be white, or would ituc1j4 t j,um.b be some other color?

  Monochromatic light falling on two slits 0.013mx5j 1.vc 90w zhabvcurr4fa.c71 eg6 mm apart produces the fifth-order fringe atcvc3e1.5z rgb j7aa 9w.rmu4c0 xv 1hf 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 angleiyj 7d1ri 8)v:aivr h- of 18$^{\circ}\,$ when the light falls on two narrow slits. How far apart are the slits?    $\mu m$

  Monochromatic light f::p*e5b5(l/wekifujtkp x,/ 3ejyk ialls on two very narrow slits 0.048 mm apart. Successive fringes i5 /ej5ibplx3:ep*yw ,tkjk/ eu fk(: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 6 har)tb l8+w+ikq*bi14 0tc wb56 nm, falls on two very narrow slits 0.060 a 8bb4*iw li0rcq)tb1+kw t+h 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 fallsk) o+/19rw5 / .mqeich agjnue on two slits and produces an interference pattern in which the fourth-order fringe is 38 mm from the)o .w+ek//9ecq1gn5jru m ih a 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 thros1d jj0i+gs u7ugh two slits 0.58 mm apart, how far apart are the second-order fringes for these two wavelengths0g jd 7u1sis+j on a screen 1.0 m away?    mm

  In a double-slit experiment, it is found that blue light of wavelength 460 nl fj2tp n,t7w/m gives a second-order maximum at a certain location on the screen. What wavelength of visible light would have a minimum at the same lotp/tfjnlw 2, 7cation?    nm

Water waves having pk6cd 0(b7wlct zyr: 7j.hoyx9arallel crests 2.5 cm apart pass through two openings 5.0 cm apart in a board. At a point 2.0 m beyond the 6h:br97zcw ckd l7.xo(ytjy0board, 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 igt4 *ds+soj5y; xm t d*-14f3umf hrtyn front of the lower slit in Fig. 24–7 so that the two waves enter the slits 1ddf +1ytoh yr;4s mgm3sxttuj-*5*f 480$^{\circ}\,$ 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 mami2 vxok: ts2z,k;: ksximum for light of wavelength 500 nm is located 12 mm from the central bright spot on a screen 1.6 m fromo x;k :mz2ss :i2k,vkt 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 liggac72n4ge6cn ht. Find the distance between adjacent bright c4ean267n gc gfringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 nm in h3nx 6sdpiua+7mk c;+,6hn ht 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) covers one slit of a double-slit app:4m lh0/lh c6 jyisp8faratus illuminated by 640-nm light. The center point on the screen, instead of being a maximum, is dark. What is the (minimum)8:l hs pc0/lh 6mjyif4 thickness of the plastic?    nm

  By what percent, approximately, does the speeamm1-ti /2cowmwhs e7fj(h8 *d of red light (700 nm) exceed that of o h8c fw7*tjawm 2ihe/m(1sm- violet light (400 nm) in silicate flint glass? (See Fig. 24–14.)    %

  A light beam strikes a piece of glb7(ruq -. gkognav,6gass 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 contai e(,mglyme en847v*mwning 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 slik v v/8nsdzzq9 l0w1aav.(d51elc ez)t 0.0440 mm wide, what is the full angular width of the central diff(z v51. ak)9e qavecnz d1zw08sl/dvlraction peak?    $^{\circ}\,$

  Monochromatic light falls on a sla 6ab (p/ gay 0qj3)+cqgtunt..wf: tyit that is $ 2.60\times10^{ -3}\;mm$ wide. If the angle between the first dark fringes on either side of the central maximum is 35.0$^{\circ}\,$ (dark fringe to dark fringe), what is the wavelength of the light used?    nm

  Light of wavelength 520 nm falls on a slit zxv ,7-t.z7rldywy+rthat 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 iv:fw,i/q0f6kv vbg n 65 -hpvalluminated by 450-nm light. What is the width of the central maximu-qvv5k afh6vpfw0n, g/bi : v6m (in cm) in the diffraction pattern on a screen 5.0 m away?    cm

  Monochromatic light hf1 d9-9/mp 8sukgbp ye,klk 2of wavelength 653 nm falls on a slit. If the angle between the fir,8 pu 9kkld 9mp12ghek-bfy /sst bright fringes on either side of the central maximum is 32$^{\circ}\,$, estimate the slit width.    $\mu m$

  How wide is the central diffraction pe8u 8s5fowz ay9ak on a screen 2.30 m behind a 0.0348-mm-wide slit illuminated by fawy5z8 s8u 9o589-nm light?    cm

  When blue light of waveleq z qi+.g:;n*v5sf yqdngth 440 nm falls on a single slit, the first dark bands og dizq* ;qf+y:5v n.sqn either side of center are separated by 55.0$^{\circ}\,$. Determine the width of the slit.    $ \times10^{-7 }\;m$

  When violet light of wavelength 415d +lhnt yaa779gzrpr m8xl-9; nm falls on a single slit, it creates a central diffraction peak tha9m+a9pzt nlhx87d g rla7;-yr t is 9.20 cm wide on a screen that is 2.55 m away. How wide is the slit?    mm

  If a slit diffracts 6jcpb; c s4.-:oei(e av4 govy;y/ni-w50-nm light so that the diffraction maximum is 4.0 cm wide on a screen 1.50 m away, what will be the width of the diffraction maximum foj-oocvc;n4/yp:( w4ei.- aeb v;siy gr light of wavelength 420 nm?    cm

For a given wavelength ez1u d;p.f*k*jj5sv mw1r2p:/a udfy $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm light pg :rfwnhf j:51roduce a second-order maximum when falling on a grating whose jf5f:r1w: nghslits 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 ) qfet-wn 0v.,t3if wedoes a grating have if the third-order occurs at anenfi3,- t).qw v0w fte 18.0$^{\circ}\,$ 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 diffraction gratino c4l,j6 9fy2/tu0vi x /maioig is observed atofy//4ju0i9,ltxi mi 6o2 ca v 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 )3q(b:*ywo - jdnusj ah3.5bmw0 sgyszs 0xb*$ 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 1ywofb4 h)u o2ydc;d*on a $9700-line/cm$ grating is revealed to contain three lines in the first-order spectrum at angles of 31.2$^{\circ}\,$, 36.4$^{\circ}\,$, and 47.5$^{\circ}\,$. What wavelengths are these?
$\lambda_{31.2}$    nm
$\lambda_{36.4}$    nm
$\lambda_{47.5}$    nm

  What is the highest spectral order that can beshx+vc*;hh/ zt)cfea8 5.pb e seen if a grating with 6000 lines per cm is illuminated with 633-nm laser light? Assume normal incidencc ve;*.x tsfb)ca hhhz5 p/e8+e.   

  Two (and only two) full spectral orders can be;mflh 4dn ;ki2 seen on either side of the central maximum when white ligh; mkil24 fdnh;t 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 falls on s,;ge,q uw)u)a0a)ic n*yw iaa grating with ciaueni)waya*, q ;g) ,)us0w $8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which produces monochrs)j u- :kjc. oqrqo-oxz41, upqj,np9 omatic 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 spectrumql5 v ;r:ank;+i7jalx 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 m d ,2ij+)8y 1bw cdz*2cwkyllreflected at the center of the outer surface when illuminated normally by white light? Assume thai2dy) 82 jwbz k1mwd,y lc*lc+t $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringes ih m5yf+ .o- 9oeq, +8hpzhvofrn Example 24–8 if the glass plates are each 26.5 cm+oy5 ,hfop.f zqh-v9ro 8h+ em long?    cm

  What is the smallest thickness of a soapka. g y5sqlb8 9ui56ei 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 ye82k; 2ett3n w exuffd/llow ($\lambda\;=\;570\;mm$ is strongest) when white light reflects from it. What minimum thickness of coating $(n=1.25)$ do you think is used on such a glass $(n=1.52)$ lens, and why? $t_{min}$    nm

  A total of 31 bright and 31 dark Newton’s rings (not counting the dark spot at7f3 lws0d5ge a0cz 7lr5m,z lt the center) are observed when 550-nm light falls normally 7 l5sgftd z,rwalem7c3zl 005 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 optically fi8vxm4*d. b me a 8sf.s4/zaz;4: 0admstvb zblat glass, as in Fig. 24–33. When light dvsat.4sb mm;b i*z/xf 8d4a4mv .azs0e : 8zbof 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 thd) 1jvy8o; xrse air layer be between two flat glass surfaces if tx vs1jd);yor 8he glass is to appear 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 stolen diamond)0dpe /czv xeh.r+))wwofk/ o $(n=2.42)$ 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 alcohol7tx.znj+ ,iqb mfd6p 7k4ygu4 $(n=1.36)$ 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 (F 6mq y opa 5)c;(qpjdh0kx1:xfig. 24–31) is immersed in a liquid, the diameter of the eighth dark ring decreases from 2.920qk5q 6a;hfxj m 1)yxodc( p:p cm to 2.48 cm. What is the refractive index of the liquid?   

  What is the wavelength of the light enteringh ir8 3tcts).m an interferometer if 644 bright fringes are counted when th)ct. 38sm hitre movable mirror moves 0.225 mm?    nm

  A micrometer is connected v 8z:+kuwu +fjto the movable mirror of an interferometer. When the micrometer is tightened down on a thin metal foil, the net number of bright fringes that move, compared to the empty micrometer, is 272. What:w++j 8vfkuuz is the thickness of the foil? The wavelength of light used is 589 nm.    $\mu m$

  How far must the mirrqrvhz qz: vodoc3sgn y86 6.;g+v,tz,or $M_1$ 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 lttun f x- ;t6z c4x; uny(o9psw)/s+han interferometer (Fig. 24–59) passes through a small glass container containing a cavity 1.30 cm deep. When at txw6z/;n+ xs( lhsyf n9uop)c;tu4- gas is allowed to slowly fill the container, a total of 236 dark fringes are counted to move past a reference line. The light used has a wavelength of 610 nm. Calculate the index of refraction of the gas, assuming that the interferometer is in vacuum. $n_{gas}$

  

  Two polarizers are oriente9*ndo2z u8nuid at 65$^{\circ}\,$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s angle fo;u. x.s3na qonce.q ,kr an air–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerged in water if the z9;ipq 8ekq(dv2z , q9igkw.ulight is hitting the diamozq8d9e9qkwigviz .,u;(p q2knd $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the l2sn8 4t*ihysz ight passing through them is a maximum. At what angle should one of them be placed so that the i i *n4szth8y2sntensity is subsequently reduced by half?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be pu he0:aykg4j/rx0l d0laced so as to reduce the intensity of the incident unpolarized l 0a: 4/jyek0rhlg0uxd ight to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oriented at 40exd i085q.2i zytv4p0*mwwxz$^{\circ}\,$ 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 2e5/3zk q/;skd +djhg 6qrb ioat 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 for5ee( phj*aw6 u x:f3lt light coming from beneath the surface? Compare to the angle for t*h(:feulw3 x5a jpe 6total 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 shhqs2yr , hija; 6:ips5eets, each of whose a,s;h26jpsa5r:i hyi qxis makes a 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength i ix2zvfv485s 7idnm,$ 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 mox8udx6yy;*ye84fn3q 4o vm yzuntains or airplanes can interfere w4y;xv6z n4fyy8xm y 3qeo*d8uith 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 separate sources passes through a diffraction grating wiet)f 3bierx .up+nv+ 3th u p+tie.n3 vfx 3+)rbe$ 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 zaa9gz b-;6do knfl; tx1d+8 ppasses 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 the central maximum than the 590-nm liz6-kgxb1a 8; +zpld;d 9ontfaght. What is the wavelength of the unknown light? $\lambda_2$    nm

A radio station operating at 102.1 MHz broadcas97tyq mk40eai ts from two identical antennae at the same elevation but separated by an 8.0-m horizontal distance d, Fig. 24–60. A maximum signal is found along the midline, perpendiculytm0i4qea k9 7ar 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 doorwaywg3k z1pb *4oyhbe)1r 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 on the plbpw ekg h4*3)o1zbyr1ayground outside the doorway.    $^{\circ}\,$ either side of the normal.

If parallel light falls on a single slit of n - rd ( rv50;d9v u39ryekb7ov5wqezlwidth D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a series of paraxtabe 4jv-hi +xq-edtz x-1 *aq . x22w7mhdn)llel lines across them. When normally incident 460-nm light is reflected from the wingjnt7qa 4tb xxdx-+ w xh mqeh21dv.e ia-)z-2*, 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 grating have if there is to be no second-o2b 6qvrw7qg(/ wrm u)trder spectrum for any visible wavelength67 u)v/gm q(tb2 rwwrq?   $ lines/cm$

Show that the second- and thirdb7(ac8 b0qkkp9v u5sl-order spectra of white light produced by a diffractionpka08qckv ( 7b5ul b9s grating always overlap. What wavelengths overlap exactly?

  When yellow sodium l5 4 yh, sur0gm:sqpvsz,k2 7szight, $\lambda\;=\;$ 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 gratz1 uh1 y+k w5a7ne.bdwing with and the pattern is viewed on a screen 2.5 m from the grating.5.+1hywnwu 1k7 eadzb 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 of a clear material if a mi1reh:mnt9e.4 vx3ip p nimum of 150 nm thickness of it, when laid onpmh9 .3it:rp1v4ene x glass, is needed 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 incidenz7vnm2(q;i .m0k vohv t normally on a thin sheet of plastic film in air. The reflected light is a minizv.v(v h o0mmik; 2n7qmum only for $\lambda\;=\;512nm$ and $\lambda\;=\;640nm$ in the visible spectrum. What is the thickness of the film $(n=1.58)$? [Hint: Assume successive values of m.]    nm

  Compare the minimum thickness needed for an anti-reflegfs z ,0ydqy1;ctive 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;/ u;gcps+r su layer between two flat glass surfaces if the glass is to appear dark when 640-nm ligh/uu+gr ;sps;ct is incident normally?    nm
What if the glass is to appear bright?    nm

Suppose you viewed the light transmitted through a a*6h)vw*z,kd(9z .yvlhqdd y 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 relativev6ywq d a9kd(l*,z).*dzv h hy 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 smooth lar5:2o crfm*wwc ehva p6: 1uuf/f:jc9 ke is polarized m or:wpj a6uuerc:1v/f* cfc hf:92mw5ost strongly?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so as t(g37c,ojdf (9 pd:b 7iob yg:8mcpbibo reduce the intensity of the incident unpolarized light by an additional factor (after the first Polaroid 9b, (i: fg7bc c8gb(bd op3miy:doj7pcuts it in half) of
(a) 4,    $^{\circ}\,$
(b) 10,    $^{\circ}\,$
(c) 100?    $^{\circ}\,$

  Unpolarized light falls on two polaav-t m-o7)kcod-i)n g7q.0v0tc gnx hc (w(lwrizer sheets whose transmission axes are at right angles. A third polarizer is placed between the first two so that itoc ov(w.w qnmxi vtck-h-g(7g- 0n0t )7dl)acs 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 successiohr /d-4 of2faun 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 a slit of width 1.0 cm and is pointed at qm3fgbrq e hj4* l:txi5j10*xthe Moon, which is approximately 380,000 km from the Earth. Assume the laserh5mtbq lj: exx*41g3 rq*i0jf emits waves of wavelength 630 nm (the red light of a He-Ne laser). Estimate the width of the beam when it reaches the Moon.    km

  A series of polarizers are each placed at a 1qi44 wsg(zmy6jgea8/ad bq-- 0$^{\circ}\,$ 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 m 57jetffjf:s 56:x,2slhj ds$(n=1.34)$ 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.-ki 1ezns vo9*0-MHz radio waves in phase with each other. They are1k9nvo ie z-s* 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 containing two wa(h 4iv*i owu gvj g42;d)6kyqevelengths, 420 nm and 650 nm, enters a silicate flint glass y)h 4v 4g(ie2j okv;gdu*iw6qequilateral 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 lensf6lb+. t r8q4k u2bo5xgo fco; has one 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