Does Huygens’ principle apply to sound waves*kj 1dqzgo p(r)bw)is0z h5n1? To water waves? Explain.

What is the evidence that light is3 2k;qftokr-qyarup2 ucmm(3 25bfr3 energy?

Why is light sometimes described as rays and sometimes as tf j*sih8cep-g ,7p,zwaves?

We can hear sounds around corners, but we cannot see around corners; yet both stp7 -ajo p2txv:i)5* b nss+.aro)pmgound and light are waves. Ertp ):mspsp+5tg)7.a- bovo ia 2nx* jxplain the difference.

If Young’s double-slit experiment were i:t qr/r,.ovu l q d(eof56al9submerged in water, how would the fringe pattel er(o6vr/9f:.dtliq,uq5 o arn be changed?

Monochromatic red light is incident on a double slit, and the interferenp3+u1 zsf9 yapw 9,u2 uzpd:gice pattern is viewed on a,dpwu u2zp3p9: 9fs u1 a+gziy screen 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 3,qq-rxsr r,h96w se asource destructively interfere if their path lengths differ by hrqqs a s9w3,xrre6,- how much?

Why was the observation of h k.v5hctuvk 3g0-cuwslytj*0 b54z7the double-slit interference pattern more convincing evidence for the wave theory of ligvg c s- whjk5l3ty0butkc z4 5.uhv7*0ht than the observation of diffraction?

Compare a double-slit b ykd+1n kawlz:tf( p31w551qr s:g ref oy.p/experiment for sound waves to that for light waves. Discuss the similaritie5kzdr3wg1p.1b fo 5n 1r :stewq/ yfp:kyla( +s and differences.

Why doesn’t the light from the two headligx. )hacm r+ul.hts of a distant car produce an interference patta. m.c rh+)uxlern?

Suppose white light falls*n hi1u9*zkmcon-3m -2 -tdc e wzzb*y on the two slits of Fig. 24–7, but one slit is covered by a red filter (700om-zkn m3e-*b* z nh d-iuwyzc91c*t2 nm) and the other by a blue filter (450 nm). Describe the pattern on the screen.

When white light passes through a flat piece of window glabznd,. ce4ulooot a 3o 9x(lm4o609w vix2)u pss, it is not broken down into colors as it is by a pris2bwo9lo0d4zxv96o imp4 c. a3,nle o uox)u(tm. Explain.

For both converging and d8f+)em;:sn l z4ylkiw iverging lenses, discuss how the focal length for red light differs from t 48w; m:l+elz)ysknfi hat for violet light.

A ray of light is refracvygzr 7dp r/i9a)4nk.ted through three different materials (Fig. 24–55). Rank the materials ar)dgvi kr/p7zyn.94 according to their index of refraction, least to greatest.

Hold one hand close to your eye and focus on a distant light source through a nazc3e v ;k,aeeb+4qn s(h cj(d,rrow slit between two fingers. ( qdve ,j(+b(3ekneha ,cc4;sz Adjust your fingers to obtain the best pattern.) Describe the pattern that you see.

What happens to the dw9cm5hnq um +r ac5ixc(75 di0iffraction pattern of a single slit if the whole apparatus is immersed in (a) water, (b) a vacuum, ins7hi cmm09d5uxqwc i5a ( cn5+rtead of in air.

For diffraction by a single slit, whats 9nc4mj4l7s ;+jevou is the effect of increasing (a) the slit width,le9mcojv+ 4sns;47 uj and (b) the wavelength?

What is the difference in the interference patterns fo.a vb z1dwj y:4*jt)icr 2)sqyrmed (a) 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) many slits, (bm+r*a 1ptalv/d qys 44; f)aml) closely spaced slvm4 dlls+;1* aayt 4fq)r apm/its?

White light strikes (a) a diffraction grating, and (b) a prism. * neb)x0wm5m:wt,sy oivd-o1A 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? Exmei:d 5m*t 1oy w,)nb-0vw soxplain.

For light consisting of wavelengths between 40xy kq+(kl p8vy12 6whd0 nm and 700 nm, incident normally on a diffraction g l8kq2xpyvw(16d+k yhrating, for what orders (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 soap bubbo+za p lf6 93cn2nxz 8,h,vefule and not for a thick piece of glass, cp 9ffl6ax,ou+venn2h 8 ,zz3 say?

When a compact disk (CD) is held at an)c rknl a,0 x-oz*8otp angle in white light, the reflected light is a full spectrum (Fig. 24–56). Explain. r)cto-a o8 znx,pl*k0What would you expect to see if monochromatic light was used?

Why are Newton’s rings (gcwk2evb a0ur0i 6jtnf5 (91wFig. 24–31) closer together farther from the center?

Some coated lenses appear greenish yellow rgn n0 -z.n.igqgtt3r+ vyaefd)/ c59when seen by reflected light. What wavelengths do you suppose the coating +.er-v inn9c yz)n dtfr.t/g3q5 0ggais designed to transmit completely?

A drop of oil on a pond appears bright at its edgn c-u:wwiaiy , 55f6yqx: f31e5a jiphes, where its thickness is much less than the wavelengths ofyc 3,ji w1 yeaa-f6w55npu:5xifi h:q visible light. What can you say about the index of refraction of the oil?

What does polarization tetl(xah z/y833-ousu ill us about the nature of light?

Explain the advantage of polar tt2*r ,3t w2 ppu8.tx7jkk..mvsnaqsized sunglasses over normal tinted sunglasses.

How can you tell if a pair of sunglassv9+ilxgu( h r,es is polarizing or not?

Two polarized sheets rotated a54yl+x v li2npxw6vy1t 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 svf x,msf- vjr+jx fh+ )c(:v(no atmosphere?

If the Earth’s atmosphere were 50 times denser than it is, would cwsp-9ldh4 xo sj:t7g0* dg0 osunlight still be white, or would it be some other7s0cgoph9w0 x * -gdstjdo l4: color?

  Monochromatic light falling on two slits 0.016 mm apart produceh o3g. 0:ivmr,nsu3 bes the fifth-order fringe at an 8.h,bs:e .mnr 0 uo3vg3i8$^{\circ}\,$ angle. What is the wavelength of the light used?    $ \times10^{-7 }\;m$

  The third-order fringe o9 6jg. tk.syxzf 610 nm light is observed at an angle of 18$^{\circ}\,$ when the light falls on two narrow slits. How far apart are the slits?    $\mu m$

  Monochromatic light falls onr*i 1 k(37gnfhxup*o r two very narrow slits 0.048 mm apart. Successive fringes on a screen 5.00 m away an(xr*7r1oghpkf 3 u*ire 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 6egqcz6l15wwf 5 mbmg*2(8vu t56 nm, falls on two very narrow slits 0.060 mm apatcef61v *mqb 5lw ugz8gwm5(2 rt. 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 on two slits and prh 4-bqg wpymp74i:m .poduces an interference 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 wp4q pmg 4:ph.-mib7yof the two slits?    mm

  If 720-nm and 660-nm light passes through two slits 0.58 mm apart, how faro7:i b (zr 4jhhrmn+n( apart are the second-order fringes for them:oh4zn r+hn(7ij(b rse two wavelengths on a screen 1.0 m away?    mm

  In a double-slit experiment, it is found that bludk( iw ne*l 2v:jg(xw* 6cg4obe 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 minimukw*b(2jo (xw*6n e4ggcvi:dl m at the same location?    nm

Water waves having parallel crests 2.5 cm apart pass through two openilb2 :jwvu0h, zngs 5.0 cm apart in a board. At a point 2.0 m beyond the board, at what anguwbvh,j lz:20 le 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 lower8qv;rdvh rr68 slit in Fig. 24–7 so that the two waves enter the slits 180q r 8rhr;8v6vd$^{\circ}\,$ 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 t:2ji )ot9lewtz3 fvl /hird-order maximum for 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. How far from the central bright spot will the second-order mlwf v 3t eij2lo/)tz9:aximum of this light be located?    mm

  Two narrow slits separated by 1.0 mm are illuminated by 544 nm light. Find t+p,fp-(i8cym qw tv:4sg xq 1 /k(zwrche distance b -g8 m+ 4wvc/1,wtpprz f(q sqxik(y:cetween adjacent bright fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 nm in air falls on two sov/kb8j,xs 7,b2mze2ih 3 ;ttlphi 3ulits $6.00 \times10^{-2 }\;mm$ 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) c,yv/c9juxh3cbd kf y k .tl0(-overs one slit of a double-slit apparatus illuminated by 640-93v bkt yk (fyhl xcdc.u0-j/,nm light. The center point on the screen, instead of being a maximum, is dark. What is the (minimum) thickness of the plastic?    nm

  By what percent, approximately, does the speed of red light (700 nm) exceedvc2l0 kn +7hzy3topa4 that of va p4yt0n3 l7c2h ovzk+iolet light (400 nm) in silicate flint glass? (See Fig. 24–14.)    %

  A light beam strikes a piece of glavjg+5/8k//1j m u50penvmhyefe (vgk ss 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 containinh*w+cq f2w x zmx*,j4j 4rq7sbg 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 q(:1yfrrs7n v9p l(ys+5 ymv son a slit 0.0440 mm wide, what is the full angular width of t+sy5yvrsf1 lnrs9: (vqpy 7m( he central diffraction peak?    $^{\circ}\,$

  Monochromatic light falls on a1xdlrhw2+5b;d xo in wd4i-0d 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 fml,fj dj/ ;5qoalls 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 m0 ngvmphjm0 t 2mztaha/eu(. 4 b28h4jtm: -ris the width of the central maximum (in cm) in the diffractiong0- 8jmhu2mt mvnhaehmatbrt 40m.(4 jz /:p2 pattern on a screen 5.0 m away?    cm

  Monochromatic light of wavelength 653 nm falls on a slit. If the an7 fib;2:6c n.cysjsrtgle between the first bright fringes ory :s;2 .c jst7ncfb6in 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 0v u f o8.sgy-o:wh6ei;.0348-mm-wide slit illuminated by 589-nm .ug:yoe;-w v86ifh s olight?    cm

  When blue light of wavelength w5 t3lx u1cv2yb8xs;e.-lwvt440 nm falls on a single slit, the first dark bands on eithe51xs tv3le.y v2w-8uwtlc;b xr 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 sn+n ty08tp43 rk, gzqyh:8daclit, it creates a centralky4tazn qc8y:p r0g8,3tn h +d diffraction peak 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 light so that t3ith6 yfv;sq9wdu 9:yhe diffraction maximum is 4.0 cm wide on a screen 1.50 m away, what will be the width of the diffraction maximum for light of wavelength uq;d yytw:96 39fvshi420 nm?    cm

For a given wavelengt +cjdw8 ;kb9pk qpk1cz+tn 2e;h $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm ligqke z7iq ls.l nq-/,ik8j+hx/hfr g7 0ht produce a second-order maximum when falling on a grating w/hqesq -gjrlfqz,7i/+nxklh 7k.i 0 8hose slits 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 doeslz*ak u-o: 6pq a grating have if the third-order occurs at an 18lua:ozpq -*6 k.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 diffreur qqt7p 2*o i,pdwe(6b-lo( action grating is observedeq6reio*p ,(qd-u 2 (blw7opt 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 ha:js j/a hc;w(zt /mk9es $ 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 qp*yodl70 ss-bku s(, 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 nw*w ot,k.b(s can be seen if a grating with 6000 lines per cm is illuminated with 633-nm laser light? st w.bw(o,nk* Assume normal incidence.   

  Two (and only two) full specac -hv-cbg jw b6:t,j7tral orders can be seen on either side of the central maximum when white light is sent througcbgwa-jj-, v tc7b:6 hh 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 , kn4chzp,xyv8h(em)to 750 nm falls on a grating withezc)( ,hp8y,4 vn mxkh $8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which ptfi1q+ d9ofbv-;mw 4b roduces monochromatic light of a known wavelength $\lambda\;=\;6.328\times10^{-7 }\;m$ is used to calibrate a reflection grating in a spectroscope. The first-order diffraction line is found at an angle of 21.5$^{\circ}\,$ to the incident beam. How many lines per meter are there on the grating?    $ \times10^{ 5}\;lines/m$

  Two first-order spectrum lines mz7: 8wnlnm8du,huwn 6f .0gwg5r; r tare 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 wczk1*e0epx 7 strongly reflected at the center of the outer surface when illuminated normally by white liweepckxz 7 *10ght? Assume that $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringes in Example 24 s8ugu(viqth01- l bh1–8 if the glass plates are each 26.5 cm lo u1 h8lu0h-b(igq1tsv ng?    cm

  What is the smallest x1y;quj;yb s*jr+ zkg(u4wy1ky4,td ka.6 vm thickness 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 y33u4ny. :lcfeixc p 9cl7+ac wellow ($\lambda\;=\;570\;mm$ 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 thee aaug*iq( m03 dark spot at the center) are observed when 550-nm light falls normally on a planoconvex lens resting on a flatu eg q0im3(*aa 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 p6++i6kh5ek mvlkote bky7:.va /y iy5ieces of optically flat glass, as in Fig. 24–33. When light o 6eh.5y 7 kkot/ivkbliym+e65+yk:a vf 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 lay** e4 x(7b1czph vfjxiw;-vnzer be between two flat glass surfaces if the glass is t evx*1-(x cjzihv*f4n ;7wbzpo 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 air32yc 7wtd)r6bmzj9qx 9 , cq 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 alcoholim2;dpm2p(,t o q5ixak ep /8u dq,gf; $(n=1.36)$ lies on a flat glass plate $(n=1.51)$. When monochromatic light, whose wavelength can be changed, is incident normally, the reflected light is a minimum for $\lambda\;=\;512\;nm$ and a maximum for $\lambda\;=\;640\;nm$ What is the minimum thickness of the film?    nm

  When a Newton’s ring apparatus (Fig. 24–31) is immersed in a liquid, m5vha g,k0os5the diameter of the eighth dag0vs,ko ha 55mrk ring decreases from 2.92 cm to 2.48 cm. What is the refractive index of the liquid?   

  What is the wavelength of the light en4q;p 2ndp,k/hn(yvoeq, v qu1tering an interferometer if 644 bright fringes are counted when the movabyepq4qp vn2 k/ dqh,u ;(,vo1nle mirror moves 0.225 mm?    nm

  A micrometer is connected to the movable mirror of an interferomete7/y.xvmfs s ea5*htv9r. 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 is the thickness of the foil? emtaxy9fh 5v*7vs.s/The wavelength of light used is 589 nm.    $\mu m$

  How far must the mirro *wy- apcslr5w.- 2khdr $M_1$ 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 int-vjk/5ejj ) ) sb q7(prjf9dzrerferometer (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 -/zsfpr ) q7kjj5j()rbd ej9vcounted 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 oriented b5g j5zuudx. 1at 65$^{\circ}\,$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s angle ffwr gbnnl )j1q9iuowbgw0 *xy+3.679zrhsg/ or an air–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s anglef oxa 0e..,jh2b)bu mv for a diamond submerged in water if the light is hitting the diamo)avm bfe 0h..b u2xj,ond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the light passing through them i-9/jzbr9sl8kbbsm)bl-iw + f s a maximum. At what angle should one of them be placed so that the intensity is subsequently rbl+b s9b/wi8j rs)9 k f-blmz-educed by half?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placek(9a6.o :qiv yxq,dli x 4dr6qd so as to reduce the intensity of the incident unpolarized light toq (9y kd. xax:di4r6 io6,lvqq
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oriented at r tepj :v v vj57-i7va4v,e9rb40$^{\circ}\,$ 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 at fnt2q o-6 u4az38.0$^{\circ}\,$ 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 reflw8 y. *ag;eb(sm:khx oections off the surface of water for light coming from beneath the surface? Compare to the angle for total internal reflection, and to Brewster’s angle awbke ;(gymx* ho 8s.: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 passess.dt-2 rp,9u ;n zumhh through five successive Polaroid sheets, each of whose dzmun2 u-,th9p .;r shaxis makes a 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength fslm2wc b;xbn 1k *t0mx c92u. h*7aii$ 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 mountains72 aa8e,p,x9 mqdmihj +m(ern or airplanes can interfere with the direct signal from th n( m,7he9iqmpra+ , axjdm82ee 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 with 6o6ak zxyeh90x 696ok eya0zh$ 3.00\times10^{5 }\;lines/m.$ The wavelengths of the three lines are $ 6.56\times10^{-7 }\;m$ (hydrogen), $ 6.50\times10^{ -7}\;m$ (neon), and $6.97 \times10^{ -7}\;m$ (argon). Calculate the angles for the first-order diffraction lines of each of these sources. $\theta_{h}$    $^{\circ}\,$ $\theta_{n}$    $^{\circ}\,$ $\theta_{a}$    $^{\circ}\,$

  Light of wavelength 590 nm passes through two narrow slits 0.689-z/ipu- f twgu zu vtlyp) bqp/:,y40 mm apart. The screen is 1.70 m away. A second source of unknown wavelength produces its secyt8/b4wy t, /izpp-)zuq:uu 9 vf-lpg ond-order fringe 1.33 mm closer to the central maximum than the 590-nm light. What is the wavelength of the unknown light? $\lambda_2$    nm

A radio station operating at 102.1 MHz broadcasts from two idm ;+dpsi 7wklf0 /6zdqentical antennae at the same elevation but separated by an 8.0-m horizontal distance d, Fig. 2d7m ; wf+qi0lzk/pd6 s4–60. 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 ansjs;, rj3npo, outside doorway 0.88 m wide, and blows a whistle of frequency 750 Hz. Ignoring reflections, estimate at what angle(s) it is not possible to hear the whistle clearly on tj 3jpno;s s,,rhe playground outside the doorway.    $^{\circ}\,$ either side of the normal.

If parallel light falls on a single slit of width mq9n y(h+e(bjn+ sa(i D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a series of parall m ipn mqgev8n(b.0(-enu z9a)el lines across them. When normally incident 460-nm light is reflected from the wing, the wing appears bright when viewed ap(abnvg) n 0n-(eq9m8 ime .zut 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 se8:sze7c3samu cond-order spectrum forcm z 37assue:8 any visible wavelength?   $ lines/cm$

Show that the second- and third-order specp;y,qp6,gz nstra of white light produced by a diffraction grating always overlap. What wavelengths overlap exactlyz,6pygn,q ;sp ?

  When yellow sodium lightb wa3izpi0w(6, $\lambda\;=\;$ 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 wit1 vv9zla;a;vg(( ; ee9 itvjqkh and the pattern is viewed on a screen 2.5 m from the grating. The incident lieva(aez l;tqg 1;(;9v 9kvivj ght 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 cleat+: mr -+agat gcy 6,t-www1jar 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 have a choice ty+ m c+6-,rtaa-watg gw:1wj for an answer?

  Monochromatic light of4)t9 dtrw,rnj drj4n,yf( a)8 igp+hr variable wavelength is incident normally on a thin sheet of plastic film in rtdri(nrf )9dg 8jy44,wrta h ,p n)j+air. The reflected light is a minimum only for $\lambda\;=\;512nm$ and $\lambda\;=\;640nm$ in the visible spectrum. What is the thickness of the film $(n=1.58)$? [Hint: Assume successive values of m.]    nm

  Compare the minimum thickness needed for an anti-r( x6u0cl4 c:jl8ln,wl1y czrfeflective coating $(n=1.38)$ applied to a glass lens in order to eliminate
(a) blue (450 nm),    nm
(b) red (700 nm) reflections for light at normal incidence.    nm

  What is the minimum (non-zero) thickness for the air layer between,7 c .6qoxad7s -brsqh two flat glass surfaces if the glass is to appear dark when 640-nm light is 7o-,dqrsx 7as6 .bhqc incident normally?    nm
What if the glass is to appear bright?    nm

Suppose you viewed the light transmitted through a thin fu tn64b6. yldtilm layered on a flat piece of glass. Draw a diagram, similar to Fig. 24–30 or 24–36, and describe 6tynb6tdl u.4the 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 reflecp5x a 4ytzd td/;n4f-nting off a smooth lake is polarized most strongly?/-dtdn z;a4yn5 xt pf4    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so as to reduce the inte f p*i2huo.dddzz 10u9/a:ffensity of the incident unpolarized light by an additional factor (after the first Polaroid cuts it in half) oa/d:f .pdeoudfi 0 *f9z1hu2zf
(a) 4,    $^{\circ}\,$
(b) 10,    $^{\circ}\,$
(c) 100?    $^{\circ}\,$

  Unpolarized light falls on two po)7myn sdf1h 44mnlj0r larizer sheets whose transmission axes are at right angles. 4dml7fr m4y sj0)n n1hA third 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 axu um :8.tjlf:+l jo9kies 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 ;/1r: qcda jew/je5,ddrd2jzt mx.a7pointed at the Moon, which is approximately 3tjm/7x ,rjc ; 1qd dz:. awe/je5r2dda80,000 km from the Earth. Assume the laser emits waves of wavelength 630 nm (the red light of a He-Ne laser). Estimate the width of the beam when it reaches the Moon.    km

  A series of polarizers argqon:f t(m.u( e each 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 6/ad/qj, q gkn ,d,rtk$(n=1.34)$ coats a piece of flat glass $(n=1.52)$ .How thick is the film if it reflects 643-nm red light most strongly when illuminated normally by white light?    nm

  Consider two antennas radiating 6.0-MHz radio waves in phase wig 8j*jn 7ev 6hmlch y*a.,z9lmvevn)5th each other. They are located at points n j*7ee v yahv )cjhl *m.l5v,gmnz869$S_1$ 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, enters *up,yg;v f/j na silicate flfu g j,p;/y*nvint 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 6j0 ,(3lpjqy iynt6mihas 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