Does Huygens’ principle apply to sound waves? To water waves? Explay 7c3l-lqvj.oq81l euin.

What is the evidence tha8q4l+yntr j mw9fma ).t light is energy?

Why is light sometimes des qywnu 3zd1rbw7:oxi0c/ 1mq7cribed as rays and sometimes as waves?

We can hear sounds around corners, but we cannot (hh uk 75lx:9 ucym/yusee around corners; yet both sound and light are waves. Explain the diffehmxucy/u(95hyuk 7:l rence.

If Young’s double-slit experiment were submerged in water, how would the fr5un e0f 2kqxl t3+cm6ninge pattern be changedke0n+53tcm ul nf62xq?

Monochromatic red light is incident on a double slit, and the interference patte 18o4rc rzv2tern is viewed on a screen some distance away. Explain how the fr8errzt1o4c 2 vinge pattern would change if the red light source is replaced by a blue light source.

Two rays of light from the f 3 cdxvo2s+6dsame source destructively interfere if their path lengc f+v6d3 dsx2oths differ by how much?

Why was the observation of the double-;/z: v +v( 0gjedqpb2e *bgf0r* zasw/rynf q,slit interference pattern more convincing evidencg:weq / 2;bzb v p+n ,ef*vfr 0ry*/jzdgs(0aqe for the wave theory of light than the observation of diffraction?

Compare a double-slit experiment fix0w:0j3j, xhbpu/ euor sound waves to that for light waves. Discuss the s,ue0xj3/ ixbu j :hp0wimilarities and differences.

Why doesn’t the light from the two / 2ghot*2icpsx w3:e (b .pmbvheadlights of a distant car produce an interference cm*e2.sp /vtw b: pihbx(3g2opattern?

Suppose white light falls on the two s54;ehz*)pg zx)gud06zr xrly lits of Fig. 24–7, but one slit is covered by a red filter (0 *6;gpdexr)l)4 zrux yz zg5h700 nm) and the other by a blue filter (450 nm). Describe the pattern on the screen.

When white light passes through a flat piece oc y; 2bi5fzm0lf window glass, it is not broken down into colors as it is by a prism.ilymfbz 02c5; Explain.

For both converging and diverging lenses, discuss how the74r8yqwpb5bvz i,d/rio. )e 2ettdx3 focal length for red light differs frobw4e odevi t2./r,t)rx 7q yzb8p5 i3dm that for violet light.

A ray of light is refracted through thr2cww92r19 tf b;e3obvwlkoejkh- 9 . ree different materials (Fig. 24–55). Rank the materials according to their index of we l2wk9for jkc;91evb 23hw rt.-9borefraction, least to greatest.

Hold one hand close to your eye and focus on a distant 8 )r4h: qwyrrqlight source through a narrow slit between two fingers. (Adjust your fingers to obtain the best patrqr)4hw y8:q rtern.) Describe the pattern that you see.

What happens to the dimd 0 hv/.c5 khpgo9t8 qe/he6dffraction pattern of a single slit if the whole apparatus is immersed in (a) water, (b) a vacuum, i9dh/0tm56.og/ k8qed hp vc henstead of in air.

For diffraction by a single slit, what is the effect of inc yur)ssf88 oy5reasing (a) the slit width, as u ysr5of8)8ynd (b) the wavelength?

What is the difference in the interf/+9nsrtdxb6a - n5yiwy;ts k .erence patterns formed (a) by two slits $^{-4}\;cm^2$ apart, (b) by a diffraction grating containing $10^4lines/cm$?

For a diffraction grating, what is the advantage6d wt )bw6gqv4 of (a) many slits, (b) closely spaced 6vqt4) bwdw g6slits?

White light strikes (a) a diffract,hv2tkyovwq o /n/-f880 um bomd q6+vion grating, and (b) a prism. A rainbow appears on a wall just below the direction of the horizontal incident beam in each case. What is the color of v2 dq6o,0v/k f8uobo m/ qnm t+hyv8w-the top of the rainbow in each case? Explain.

For light consisting of wavelengths betwe 0jx3j hto h*a 2k2g.jem3l6iken 400 nm and 700 nm, incident normally on a diffraction grating, for what orde22aetho 3 kjm.i0jhg* j63kl xrs (if any) would there be overlap in the observed spectrum? Does your answer depend on the slit spacing?

Why are interference fringes notgsi c +e(h0.lticeable only for a thin film like a soap bubble and not for a (hscg.ti 0+el thick piece of glass, say?

When a compact disk (CD) is held at an angle in whirxrsu818 hjve1b raz)x6l 8*kte light, the reflected light is a full spectrum (Fig. 24–56). Explain. What would you expect 1jex1 868vba* urhzk8sxr l) rto see if monochromatic light was used?

Why are Newton’s rings (Fig. 24–31) clofyh *r3.1m 2z,xdo ww0 7v yem(iwqe;qser together farther from the center?

Some coated lenses appear greenish yellow when seen by refj 4bnox:h-o9xj y6deej n 28:xlected light. What wavelengths do you suppose the coating is desixy2j b8 6jee :h4dn-noo9 jx:xgned to transmit completely?

A drop of oil on a pond appears bright at its edgesd1 ivxdf:nv* d /8+eos, where its thickness is much less than the wavelengths of visible light. What can you say about v1 de*ifsnodd :/vx+8 the index of refraction of the oil?

What does polarizatiqawrtf n38*ol qif /oh;fd(no2 d *9*ron tell us about the nature of light?

Explain the advantage of polarized sunglasses over normal tinted vc 3*9kt fz)cn7x jm)isunglasses.

How can you tell if a pair of sunglasses is pola8gz/uyt74 yprrizing or not?

Two polarized sheets rotated at an ug +t81dfcf58emh mwt++ (lphangle 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 atmosphereb2zja 3a- cma,?

If the Earth’s atmosphere were 50 times denser than it is, woulddia0/ktk uzar 33f7rz+r z85fs5z /od sunlight still be white, or would it be some s za +3odrrd zz0/fut/k85 3akfzi5r 7other color?

  Monochromatic light fal- 4igi08mx mjy ht07mvling on two slits 0.016 mm apart produces the fifth-order frivmmhj4 70ti gm-8 0yxinge at 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 obseram -7pe+ym *1bh8r9ms ymjq a29i18hjhi5 f pqved at an angle of 18$^{\circ}\,$ when the light falls on two narrow slits. How far apart are the slits?    $\mu m$

  Monochromatic light falls on two very narrow slits 0.048 mm apart. Successive fars3w).5:ydhv k 3gb hringes 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 lsb3vkh:)r 3y 5hd agw.ight.
$\lambda\;=\;$    $m$
$f$ =    Hz

  A parallel beam of light from a He-Ne lasbth/lxil + 2c3n*wq ,n41sqqqer, with a wavelength 656 nm, falls on two very narrow slits 0.060 mm apart. Hlx , n hwc q/stqqn12b+*li34qow far apart are the fringes in the center of the pattern on a screen 3.6 m away?    cm

  Light of wavelength 680 c cj c0+efcw4wf*q ++nnm falls on two slits and produces an interference pattern in which the fourth-order fringe is 38 mm from the central fringe on a screen4c+jcc0f*ww+f + ec qn 2.0 m away. What is the separation of the two slits?    mm

  If 720-nm and 660-nm light passes through two slits 0.58 mm apart, how far ap(dsjsofq4- ,9wj ge7c art are th-(ecoj,7qw jds4gs f 9e second-order fringes for these two wavelengths on a screen 1.0 m away?    mm

  In a double-slit experiment, it is found that blue l e4mi;4jvk:j ym(8c szight of wavelength 460 nm gives a second-order maximum at a certa ck 4mzsv8;4y (ejmij:in location on the screen. What wavelength of visible light would have a minimum at the same location?    nm

Water waves having parallel crests 2.5 cm apart pass through two openings 5.0 c xbt e9on+m1n2m apart in a board. At a point 2.0 m beyond the board, at what angle relative to the “straight-through” direction would there be little or no wavn29 mob1e nxt+e action?

Suppose a thin piece of glass is placed;dqc i- (nnhw izbqxnc6qv3 920aye- 5 in front of the lower slit in Fig. 24–7 so that the two waves enter the 3 nxnvdiec0;(zyqhin a-96cqw - 25qbslits 180$^{\circ}\,$ out of phase (Fig. 24–57). Describe in detail the interference pattern on the screen.
24-7
24-57

  In a double-slit experiment, the third-order maxwa ))nhyudr gu;q- +4pimum 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 bria r ;u+ gw4pn)hd-qy)ught spot will the second-order maximum of this light be located?    mm

  Two narrow slits sepyl90v6 +- nqizguo qh,arated by 1.0 mm are illuminated by 544 nm light. Find the distance between adjach9+vqonq6z0i- ugl, y ent bright fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 n .1y6bw89kb9dgrrpchm in 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=vu2,oa xkaemxr;-6t+p/k k g41.60) covers one slit of a double-slit apparatus illuminated by 640-nm light. The center point on the scrx+o2a4e6;k/aukm t - , xvkrgpeen, instead of being a maximum, is dark. What is the (minimum) thickness of the plastic?    nm

  By what percent, approximately, does the +r5rfdmy 00 n/wosq,luk c0yim70x 4qspeed of red light (700 nm) exceed that of violet light (400 nm) in silicate flint glass57uo,krxl 0+iydm0mq/ c s fy04w0 rqn? (See Fig. 24–14.)    %

  A light beam strikes a piece of glass at a -uqir( /8knz m60.00$^{\circ}\,$ 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 ligh3zvv ;c 5lzj7oi( mvm7t containing 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 slit 0.0440 mm wide, what is the full angular wi;jj+i8j( d*k pla(dnm dth of the dij+km( ; djl*8(pa jncentral diffraction peak?    $^{\circ}\,$

  Monochromatic light falls o.wzg7o h e 3 :5o-2ljxvahxk-(o yx(zqn 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 slit that n ylg:pq: .6qmis $ 3.20\times10^{ -3}\;mm$ wide. Estimate how far the first brightish diffraction fringe is from the strong central maximum if the screen is 10.0 m away.    m

  A single slit 1.0 mm wide is illuminated by 450-nm light. What is the width j-1m(i4lw 3j kal3 dcxry dw2;of the central maximum (in cm) in the diffraction pattern wrc3w dkal ;31 yxmd(-24iljj on a screen 5.0 m away?    cm

  Monochromatic light of wavelength 653 nm falls on a slit. If the tqe4v+sd z ;y1ek5p1qangle between the firqq+ 5 ypkve 1;se1tdz4st bright fringes on either side of the central maximum is 32$^{\circ}\,$, estimate the slit width.    $\mu m$

  How wide is the central diffraction peak rc10*/ kxyvg9vg/vt n on a screen 2.30 m behind a 0.0348-mm-wide slit illuminated by 589-nm light /91yvtngv gck*xr /0v?    cm

  When blue light of wavelength 440 nm falls on a single slit, th.gyk(5efa - vsg9ubu/x65m w ke first dark bands on either side obx u - sfmvg.g(wk5ua/k6e5y9 f center are separated by 55.0$^{\circ}\,$. Determine the width of the slit.    $ \times10^{-7 }\;m$

  When violet light of 2sl95tdyz7k gstj (5 u2lp 1mmwavelength 415 nm falls on a single slit, it creates a central diffraction peak that 2 2l5gpuyst7lsd t (jzmk91m 5is 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 the diffraction maximumo)eg.u8mjm 5l kg+a5vi-. otf is 4.0 cm wide on a screen 1.50 m away, what will be the width of.5 -kfgoe . lg)u+ ojm5taiv8m the diffraction maximum for light of wavelength 420 nm?    cm

For a given wavelength*l0 o)i q4ni/hqx2rca $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm lighnm4wv+(9 za;edhv xb2 t produce a second-order maximum when falling on a grating whose sliz;va+2x bnev4dm9w(h ts are $1.45 \times10^{-3 }\;cm$ apart?    $^{\circ}\,$

  A $3500-line/cm$ grating produces a third-order fringe at a 28.0$^{\circ}\,$ angle. What wavelength of light is being used?    nm

  How many lines per centimeter does a grating dwt76 p 3)jshxfulz 2:vjod))have if the third-order occurs at an 18.o2: uvhdlzx3jt) pf7d6j )w)s 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-nihzqk(z3n4l- d/k 9 w4nnm-hom light falling on a diffraction grating is observed at(/n 49hhimqk4-zkn-z3 d lnow a 15.5$^{\circ}\,$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction gratingzxg k (.p+4oqx 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 on swl+c :pgau23 a $9700-line/cm$ grating is revealed to contain three lines in the first-order spectrum at angles of 31.2$^{\circ}\,$, 36.4$^{\circ}\,$, and 47.5$^{\circ}\,$. What wavelengths are these?
$\lambda_{31.2}$    nm
$\lambda_{36.4}$    nm
$\lambda_{47.5}$    nm

  What is the highest spectral order that can be seen if a gratingq(c, xhsz-*haij o*e7 with 6000 lines per cm is illuminated with 633-nm laser light*cq x isoja*,ehh 7-z(? Assume normal incidence.   

  Two (and only two) full spg3jx7vhgj fk/ c 4.xq /u)qr;qvyw (m/:qf:nwectral orders can be seen on either side of the central maximum when white lighq4yvjqw:f/r:/qw. xkj 3 cg (7umhf x;g/)vn qt 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 from9ffv/m .dzs6h fal(x5 410 nm to 750 nm falls on a grating with 96 xffasz(5. h/fdvml $8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser which produces monochromatic light. kz4rls d/;,sxm *hhd 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 are measured by oy t ga)k)c bcj*j.u::d0- ujxa $9500-line/cm$ 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, whoam.i)o) dj 53.lgau+ebp9ll at wavelength is most strongly reflected at the center of the oul. a5dm la3jb )9.oe+g)lioputer surface when illuminated normally by white light? Assume that $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringes in Example 24–8 if the glass plates are (dsxhqldv.24 each 26.5 cm lxd 4hvl2qds.(ong?    cm

  What is the smallest v n9kf1)m8 lbvjaf-jyco 8fn 5l ,f)y7thickness 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 yellownxq4 mc.k(mn0 ($\lambda\;=\;570\;mm$ 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 countingu gcdml, pl93lf 5a5h:0zwckn +dvo8) the dark 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 thalp9+:v 5z,h5oc0 8g3wkclfml)dad un n the edges?    $\mu m$

  A fine metal foil separates one ej.:mc -bsht+./ooas:hp, gps nd of two pieces of optically flat glass, as in Fig. 24–33. When light of wavelength 670 nm is incident normally, 28 dark lines are observed (with one at each end). How thick is the fh g-ca. mh+j:pps o/s.ts,b:o oil?    $\mu m$

  How thick (minimum) should the air layer be between two f49+dhv i8ngjile9c0ulat glass surfaces if the glass is to appear brige8dl vu4ijn +9i0chg9 ht 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 sck0v2 fi7hy/l8vv8ys tolen diamond $(n=2.42)$ is submerged in oil of refractive index 1.43 and illuminated by unpolarized light. It is found that the reflected light is completely polarized at an angle of 59$^{\circ}\,$. Is it diamond? ----待选择----yesno 

  A thin film of alcoho d6qz:p r g44 *;va of)yx*qrql2uuz0gl $(n=1.36)$ 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. 24–3q)8vj- mrulww16kth,j q0 . xf1) is immersed in a liquid, the diameter of the eighth dark ril v8kmwt.0 ,w6uhjr )q1qf-x jng decreases from 2.92 cm to 2.48 cm. What is the refractive index of the liquid?   

  What is the wavelength of the light enteseziz mthzh/ (- fs-d 449t+iering an interferometer if 644 bright fringes are counted when the movable mirror moves 0.225 hts9e em4zs-fhii/ zt( z-4+dmm?    nm

  A micrometer is connected tox i36xgx) 0i5oyfq- sn8kh.s m:2qp to 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 is the thickness of the:sx - kng35i m)qqosh0.p 8 xo2xtif6y foil? The wavelength of light used is 589 nm.    $\mu m$

  How far must the mirro8q;8t 4rla iwcr $M_1$ in a Michelson interferometer be moved if 850 fringes of 589-nm light are to pass by a reference line?    mm

  One of the beams of an interferometer (Fig. 24–59) pasecqm5d2a7s yqn c:v epy8 v8d-(*6vszses through a small glass container containing a cavity 1.30 cm deep. When a gas is allowed to slowly fill the container, a total of 236 dark fringes are counted to move past a reference line. The light used has a wavelength of 610 nm. Calculate the index of refraction of the gas, assuming that the interfezcd:p8vqa7 yn5s e 6d svv-*m8y q(e2crometer is in vacuum. $n_{gas}$

  

  Two polarizers are oriented a4 q lcc8l,evm :2c6vykpen)6ft 65$^{\circ}\,$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s angl :lxgsj-7 yo*qe for an air–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submm ,5, +b*8sqodsnlsza fi*t3cerged in water if the light is hitting the8ztn bs ol 3qf*ia,ssc* ,md5+ diamond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the light passing through them is a maximum. A,3dli s7vzasj-(v8: v-q * az7doxcckt what angle s xda7vqzv:-cdo c kilzja vs,87(- *3should one of them be placed so that the intensity is subsequently reduced by half?    $^{\circ}\,$

  At what angle should the axes of two Polaroidsi yg(t a9j/jmn6qx,gga t/4 5nqjd,bq 4vk+7k be placed so as to reduce the intensity of the incident unpolariz9q,(+,d67ax/ j5bknnk g 4qttv ya4i/ qj mjgged light to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oriented te.3+-cohuwf( z+xam.v wd :b 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 oriente 1sj5;ln4g imed 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 f.ty35)h3yt-x4 3phkyf u e lplor light coming from beneath the surface? Compare to the angle for total internal reflection, and to Brewster’s angle from above th f5 pt4yyluytk3e3 -hph )x3.le 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 Pf (xwd.l rb5xo,4ors 3olaroid sheets, each of whose ax3,wfr d x.s(5rolob4xis makes a 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength 7r*5zb-to ki(fe;maecw;y j3or*kr)$ 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 mo vio/3 zwr44iquntains or airplanes can interfere with the direct signal from the sw 44iq /iozvr3tation.
(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 +.bp3dcz bi:m through a diffraction grating with 3 b+bdc m.:izp$ 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 tvk9 s;j8o lqq m+:v qdn80yfc9hrough 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 1.9d9nmq8v;cq +ovk :8lfyjq0 s33 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 broadcastjl hbj,rt(va(xy rk4jv;36 *f s from two identical antennae at the same elevation ;rhv6 j l4*jbtv(j rky x(3f,abut separated by an 8.0-m horizontal distance d, Fig. 24–60. A maximum signal is found along the midline, perpendicular to d at its midpoint and extending horizontally in both directions. If the midline is taken as 0$^{\circ}\,$, at what other angle(s) $\theta$ is a maximum signal detected? A minimum signal? Assume all measurements are made much farther than 8.0 m from the antenna towers.

  A teacher stands well back from an outside doorway 0.88 m wide, and blows a whz xrjo1q7*,hlistle of *7xzljq, o1 rhfrequency 750 Hz. Ignoring reflections, estimate at what angle(s) it is not possible to hear the whistle clearly on the playground outside the doorway.    $^{\circ}\,$ either side of the normal.

If parallel light falls on a single d.f/j; ma0 1a;. knizjm m0s5tywt0q uslit of width D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a series of ec-.y,qxo :tp hv5jo :9mb q/kparallel lines across them. When normally incident 460-nm light is reflec -/kt.vmx p,bo9hq::yq 5ejocted from the wing, the wing appears bright when viewed at an angle of 51$^{\circ}\,$. How far apart are the lines?    nm

  How many lines per centimeter must a grating have if there is to be no s( co/5 5q0py84y jrtkchte7b gecond-order spectrbyq ecp/y7 5ro tkh408jt(c5g um for any visible wavelength?   $ lines/cm$

Show that the second- and sv-z14rsspy8 *s5wf : :x xxjfthird-order spectra of white light produced by a diffracz 1sfx4fv8:*spj wsx sr- 5y:xtion grating always overlap. What wavelengths overlap exactly?

  When yellow sodium light, + t3flb vszya;52jjd5$\lambda\;=\;$ 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.voepq8nt + 8fel3b4j grating with and the pattern is viewed on a screen 2.5 m from the grating. The incident light beam consists of two wavelengthsjvqeto8 fnleb43 .8+p, $\lambda_1\;=\; 4.6\times10^{ -7}\;m$ 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 minimum of 150 nm thick gy1 1uwyl/s5q:z1zf )u7gqrb ness of it, when laid on g:1qzyqg lg5 1s/ryu7wz1)fu blass, 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 rou/ h3 ap gzvj,h 2*j;b4aq(fincident normally on a thin sheet of plastrvj(haq 4 , hub*fz/aopg3;j2 ic film in 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 ru: zb067k/oo/) zrdiv 6huinfor 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/ijd* a qtisbad 1)u1 vqg6:v( for the air layer between two flat glass surfaces if the glass is to appear dark when 640-nm light is incivj d:bi tsgu(qq1i /d1aa v*6)dent normally?    nm
What if the glass is to appear bright?    nm

Suppose you viewed the light transmitted through a thin film layet68z:w0dbjv) pl gk -vred 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 relative size of the minima compared to the maxima and to zero. w8tg zjp0ldk6b):vv-
24-30
24-36

  At what angle above the horizon is the Sun when light reflecting off a smve ocacfr7x(- 2kf;c *ooth lake i(7;2vrcxea f kc-fco*s polarized most strongly?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so as to reduce *jy he py4n. a:lcp5n7the intensity of the incident unpolarized light by an additional factor (after the first Ppjh:.a*4 n cyyep l7n5olaroid cuts it in half) of
(a) 4,    $^{\circ}\,$
(b) 10,    $^{\circ}\,$
(c) 100?    $^{\circ}\,$

  Unpolarized light falls on two polarizer sheexs br7ji tz y toqq4)+om/)z0(ts whose transmission axes are at right angles. A third polarizer is placed between the firs)7q+is mt(0oj)qoz tbry /x4zt 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 tur8t;z69* zmjx y;)t4r rakg 8hxr f*mheir 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 iy9+xmd7:cg mo s pointed at the Moon, which is approximately 380,000 km from the Earth. Assume the laser emits waves of wavelength 630 nm (the red light of a He-Ne laser). Estimate the wixco: m7dm9 gy+dth of the beam when it reaches the Moon.    km

  A series of polarizers are each p(ua(s8 amrj)x laced 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 z;ytf5 ok- o8j$(n=1.34)$ 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 with each other. Tw8i 6;vjmesvkxw1 b*. hey 8mjv1*; ivksex 6wwb .are 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 co ffcf8i,-0 lfontaining two wavelengths, 420 nm and 650 nm, enters a silicate flint glass equilateral prism 0foff-fi,8lc (Fig. 24–58).
(a) What is the angle between the two beams leaving the prism?    $^{\circ}\,$
(b) Repeat part (a) for a diffraction grating with    $^{\circ}\,$

  A Lucite planoconvex lens has one flat surface and one wit;i+:kanjg t i(sa p+et;:( lujh $R\;=\;18.4\,cm$ 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