Does Huygens’ principle apply to sounrorp5ad8-li- o/nb0rpc1)z ,9u lpe2 ui7 trdd waves? To water waves? Explain.

What is the evidence that ligh t5m13 7d:cggc oaqx2f g;ddj-t is energy?

Why is light sometime:1bl4**a tr (hspn :axcrg/g qs described as rays and sometimes as waves?

We can hear sounds around corners, but we cannot see around corners; yet both9gxgs4jb4ylhy fz 3(9 sound and light are waves. Explain thh9 (zx4gfj3y9syglb 4e difference.

If Young’s double-slit experiment were7.ikgiss)jnc3) xx7 8jlg ; mi submerged in water, how would the fringe pati)g7s7 x l.8 gxn;j3jim isk)ctern be changed?

Monochromatic red light is incident on a double sp xnyimo+39* slit, and the interference pattern is viewed on aom9*+iyxpns 3 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 source destructively interfere if their path ha)lcrcno8.fiq(y )f gi8n) 3lengths differ by how much?))hc nicif3o. 8)y8gr(afl q n

Why was the observation of the double-slit inte+d*5 zpfor kt6rference pattern more convincing evidence for the watr*fop6zd+5k ve theory of light than the observation of diffraction?

Compare a double-slit experiment for sound waves to that for*v ) pm5:ydmk:ab8 wpn light waves. Discuss the similaritie:p n8vm*)by :5dawpmk s and differences.

Why doesn’t the light from the two headlights of a distant car produce t(* t5wci*w9kgdboiwt5z 3 p; an interfereo;5pkdzw3wb5 tiwt* 9cti( g*nce pattern?

Suppose white light falls on the two slits of Fig. 24–7, but one slit k5w4fc c 6v5/3mas iqgis covered by a red filter (700 nm) and the other by a blue f5m / cs4gf35qk v6wcaiilter (450 nm). Describe the pattern on the screen.

When white light passes through a flat piece of window glass, it is not broken d ho g)i(*m q32wvpn0iblj1qp 9oi1p *(9qj)v2hb o p3liqgwm0nwn into colors as it is by a prism. Explain.

For both converging and diverging lenses, discuss how the focal length for red s4vj5 f;0p7 qge*x .kwg,mxfblight differs from that f,jgqx0f5*.4xw f vskmp;bg7e or violet light.

A ray of light is refracted through three different material uyoc -dyjg/ +/9j4:qscq/0.lu tlawws (Fig. 24–55). Rank the materials according to ocu uaj s. l0y-j+t wql9/cd/qw/yg4:their index of refraction, least to greatest.

Hold one hand close to your eye n d50v t.b0nsland focus on a distant light source through a narrow slit between two fingers. (Adjust your fingers to obtain the best pattern.) nsdn0vbt5l. 0Describe the pattern that you see.

What happens to the diffraction pattern of a single slit if the wha9j5hi1*mgucg , 8ahi0foe h*ole apparatus is immersed in (a) water, (b) a,5aegfo jhh98ii 01h mg*c* ua vacuum, instead of in air.

For diffraction by a single slit, what 4omp 8bz1utt- is the effect of increasing (a) the slit width, pb1mt 4o-tu8 zand (b) the wavelength?

What is the difference in the interference patterns formed (52wa(p2x h 6*de*a;vck ldna la) 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) olmm +n);0jlqmany slits, (b) closely spaon;qmlj l+)0 mced slits?

White light strikes (a) a diffraction grating, and (b) a prism. A rakhk)pd:1 ehqg/ z )1vjp vl4sahz**2oinbow appears on a wall just below thea)lv z/q h)p:z*1v1ejgd4 2hko khp*s direction of the horizontal incident beam in each case. What is the color of the top of the rainbow in each case? Explain.

For light consisting of wavelengths between 400 nmlkbgid e/1)de5n24g*j9rk ,dzdf sc. and 700 nm, incident normally on a diffraction grating, for what orders (if any) would there be over*e/1cjd.),ks9bk dg 2zdi dl5rn4 fgelap 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 bue8d w*jcr+rq2 dqan.( bble an(*rnjrdw2qdqa+ c.e8 d not for a thick piece of glass, say?

When a compact disk (CD) is held at an angle in white light, the reflecteb v9+-zma/j5b7jjw v ad light isaja w-jmv+5z/7 b v9bj a full spectrum (Fig. 24–56). Explain. What would you expect to see if monochromatic light was used?

Why are Newton’s rings (Fig. 24–31) closer together farther frjf qxg7i.j7tof6z 0 i;errum+/ hh 90gom the center?

Some coated lenses appear greenish yello w6c)ud rfg mw9; 6xfxolq*0t;w when seen by reflected light. What wavelengths do you suppose the coating xw oxg6f*;fl60 w9t; drqu)mc is designed to transmit completely?

A drop of oil on a pond appears bright at its edges, where its thickness is x+ dzv2y8/*jzfus5h cmuch less than the wavelengths of viz hd *5fjuc2+syv8zx/ sible light. What can you say about the index of refraction of the oil?

What does polarization tesokn gb27c*1x ll us about the nature of light?

Explain the advantage of polarized sunglasses over normal tinted sun2 rpi5v d1fh;3xjs f5 n(grlu(glasses.

How can you tell if a pair of sunglasses is polariz9mhow /fo;nt3 ing or not?

Two polarized sheets rotated at ad.eum+ s /z6pk c+a7pin 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 col 2 yd4/mserzvnl4t41for of the sky if the Earth had no atmosphere?

If the Earth’s atmosphere were 50 times denser than it is, would sunljzh(k8l,)7jwerchct-hgg 3cl7 , l y9 ight still be white, or would it -cc8(t 9)7ehlzrjy3 hgcwl7,hlgj k, be some other color?

  Monochromatic light falling o6 ufb3(igue ent0,8 vxn two slits 0.016 mm apart produces the fifth-order iuet, gv 8efx360bn (ufringe 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 observed at an bxl;,xa3 z2sqxb4o d7angle 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 na a(km zt j1f)ds6n*:7elxm vy-rrow slits 0.048 mm apart. Successive fringes on a screen 5.00 m away are 6.5 cm apart near the center ofk-ym6*) (en dfs71jav mzt x:l 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 6j)ry3ra07.o1c0zs2p5tw g qfxg 7rf +*gmm r m56 nm, falls on two ve7m c*0qxr7pf+rmg2 gyw 0 rjrgs1).t5 3f omazry narrow slits 0.060 mm apart. How far apart are the fringes in the center of the pattern on a screen 3.6 m away?    cm

  Light of wavelength 680 nm falls on two slits and produces ws 0xe 56/jorqan interference pattern in which the fourth-order fringe is 38 mm from the ce05rsej/wo 6xqntral fringe on a screen 2.0 m away. What is the separation of the two slits?    mm

  If 720-nm and 660-nm light passes through two slits 0.58 mm a6+ufbk ,kc lcq )m-v0tpart, how far apart are the second-order fringes for thes+,ck- mb qtfulc0k 6v)e two wavelengths on a screen 1.0 m away?    mm

  In a double-slit experiment, it is found that blue light of wavelength 460l38mut8r(gx7j4 x di x nm gives a second-order maximum at a certain location on the screen. What wavelength of visible light would have a minimum at the same locatd4i7x8t8rlug (xx3m jion?    nm

Water waves having parallel crests 2.5 cm appg wbu v,f* job+.-0qsart 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-through” directiob+.v,pq* s0o- g jfwubn would there be little or no wave action?

Suppose a thin piece of glass is placed in front of o,:/fjt(oh. pb:aiqnthe lower slit in Fig. 24–7 so that thpa/f t.b::jn i ,qhoo(e two waves enter the slits 180$^{\circ}\,$ out of phase (Fig. 24–57). Describe in detail the interference pattern on the screen.
24-7
24-57

  In a double-slit experim p(3rzn8k j.g x)x1tocent, the third-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 maximum of thzgkxj() .oxpt 31rcn8 is light be located?    mm

  Two narrow slits separated by 1.0 mm areh8(1d t)x scsq illuminated by 544 nm light. Find the distance between adjdsc8st qhx(1) acent bright fringes on a screen 5.0 m from the slits.    mm

  Light of wavelength 480 nm in air falls on two slits /rrxndo :9b5s $6.00 \times10^{-2 }\;mm$ 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 doublem fdd7e1 kv/2b-slit apparatus illuminated by 640-nm light. The center point on the screen, instead of being a maximum, is dark. What 7fd kb1v/e dm2is the (minimum) thickness of the plastic?    nm

  By what percent, approximately, does theyj dd8bcmt q4 g6,.khvl-:2 ua speed of red light (700 nm) exceed that of violet lighgvjk 6t lcduqmyd -b8,:2ah.4t (400 nm) in silicate flint glass? (See Fig. 24–14.)    %

  A light beam strikes a piece of glass ajpwtq0/rcs2 9w q;9z)kiq7n dt 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 wai3 z/e8 ekfmx-tjyx( 7velengths, $\lambda_1\;=\;450\;nm$ 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 width o 3( fq r92yfowi-r*c7vgijzrha/4 y*jf the central diffractirf9 r3yvoy-fcizwahj (j*q72/ 4i* gron peak?    $^{\circ}\,$

  Monochromatic light falls on a slq: mhme3g9 0..fhbtyy it 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 i +lifem6 )fq)ssgj;:l :tcg9vs $ 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-nmly dry,0p(4u5 ujj+t3h2 iy il light. What is the width of the central maximum (in cm) in the diffraction pattern on a screen 5.0 m away iu4uj +t,y ir(d 32y5ly0pjhl?    cm

  Monochromatic light of wavelength 653 nm falls ox,y tlg-r x74z6)xi4wlr w8evn a slit. If the angle between the first bright fringes on eitherr it44g)8ex ,v67-w xlylzxrw side of the central maximum is 32$^{\circ}\,$, estimate the slit width.    $\mu m$

  How wide is the central diffraction peak on a scree)-znh4t .4fo h5dimr )1tjnomn 2.30 m behind a 0.0348-mm-wi4) mohd).n4 on-1tirf zjtmh5de slit illuminated by 589-nm light?    cm

  When blue light of wavelength 441c55tkfu 1krb 0 nm falls on a single slit, the first dark bands on either side of center are separattu b kf1r5ck15ed by 55.0$^{\circ}\,$. Determine the width of the slit.    $ \times10^{-7 }\;m$

  When violet light of wavelength *s(u5wwf1jx 36ql6yj1cplxie2,wk k 415 nm falls on a single slit, it creates a central diffraction peak that is 9.20 cm wide on a screen that is 2.55 w1ksk3wil *epxf6ql 6uj,1 xcw5y( 2j m away. How wide is the slit?    mm

  If a slit diffracts 650-nm light so that the diffr2 kuww96iszvw7qcz 0(action maximum is 4.0 cm wide on a screen 1.50 m away, what wil6k 9wu7zic20 q(w wvszl be the width of the diffraction maximum for light of wavelength 420 nm?    cm

For a given wavelengt1yb/-d ljgfs/ h $\lambda$, what is the maximum slit width for which there will be no diffraction minima?

  At what angle will 560-nm light produce a second-order maximum when falling on a 1v-jfjrrat9qc lp76/q.hy: a gratiny1./v9: 7fpt j-ajrhq arqcl6 g whose 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 does a grating ke qq9i64i eq:a3:r; euynb -bhave if the third-order occurs at an 13 eak 9n6 :qr:by;qi4ib-eeq u8.0$^{\circ}\,$ 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 grati,p, *dd* c8,cy6u c;peocav6fztlnv0 ng is observed aeda 6 y8n6fv,z*, pdpvccuctc, ;o*0lt a 15.5$^{\circ}\,$ angle. How far apart are the slits?    $\mu m$
At what angle will the third order be observed?

  A diffraction gratino4s--pp* kyl*qz 9oma(lob8nndh37q 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 on as- /v2w :0ty.)ttxyji 0:hnrs tlgx3i $9700-line/cm$ 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 spectralg05/md. bb vl8cn s7jw order that can be seen if a grating with 6000 lines per cm is illuminated with 633-nm laser light? Assume normal incidence.bn8s0.v gb jlmcd7w5/   

  Two (and only two) full spectral orders can be seen on e q; 29yzi+f qc7ko:gsi vvso*-ither side of the central maximum when white light is9iv2f7+i *qsq -oz ckgo;sv: y 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 zh;xv b h(s oa szh)0iqy239,efalls on a grating with )b ;hsxyo9h0 32q,(ihz aze sv$8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away?    m

  A He-Ne gas laser whi0sq sll w8rv6+ (8ypsnch produces 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 are measured by dsl -o2;dsrmjk4j 8r; 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 p0auw1q-+p a00 irheymost strongly reflected at the center of the outer surface when illuminated normally by whipr+0qe0u a wi-01hapy te light? Assume that $n\;=\;1.34$. $\lambda$ =    nm ,which is an    -  

  How far apart are the dark fringes kv1u8 oppqgewg*ln6w0;a2h7rkv ) -oin Example 24–8 if the glass plates are each pkwko8)n au6vwqgeprv- 2;o70ghl*1 26.5 cm long?    cm

  What is the smallest d1 d;wvhev9;z*.jfsm 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 yelhm4kxk vp7pn,8ndrh bf;, +h9low ($\lambda\;=\;570\;mm$ 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 counti9zh3my-dhbt6 z vam 9:ng the dark spot at the center) are observed when 550-nm light 69mzyb hvzm-a :dt9h 3falls normally on a planoconvex lens resting on a flat glass surface (Fig. 24–31). How much thicker is the center than the edges?    $\mu m$

  A fine metal foil separates one end of two pieces of optically flat glass, a1dj; p8e4* ccyotkc6i.k 5m2fr eq; ies in Fig. 24–33. When light of wavelength 670 nm is incident normally, 28 dark lines are observed 2ef; i mpd5cj6r4 ;c.tk ckq ioy*ee18(with one at each end). How thick is the foil?    $\mu m$

  How thick (minimum) should the air de1ssnk;;4a 8vv1 i cv+une:t layer be between two flat glass surfaces if the glass is to appear bright when 45 u8v;iaek 1vnnd+e s4cv 1t;s:0-nm light is incident normally?    nm
What if the glass is to appear dark?    nm

  vA piece of material, suspected of beingq jf /gw:zc31h 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 alcohfl,vpspyxk l r00c,;zk ;+txff4:.l fol $(n=1.36)$ 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 hbx.5b 9ra /ovliquid, the diameter of the eighth dark ring decreases from 2.92 cm toxr/v. 9 bhba5o 2.48 cm. What is the refractive index of the liquid?   

  What is the wavelength of the light entering an interferometer if 644 bri*hbdka9 :19w qg pfkamcx6 ;x e*l07lyght fringes are counted when the movable mirrfe9 ac7khp0 mak9w*g;*dylx6b1 qlx :or moves 0.225 mm?    nm

  A micrometer is connected to t kur3r0gjl 3)*hgj/c(e+ zxb 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 (/j3+uc)*l xeg0 kgt brh zrj3the 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 mirqhn7/u tm6 x-i.t1/up 46(f cimnbfagror $M_1$ 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) passes through a sma*ccxmvov ( +m9vruf h(v m-nm 3:g9l4rll 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 cn cm9vx*m-vh lg+mm o(:4v93rc u vrf(ounted 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 at 6 0h ;brxvlrz1k6ynzvr88ub 9/5$^{\circ}\,$ to one another. Unpolarized light falls on them. What fraction of the light intensity is transmitted?   

  What is Brewster’s angl gj0w rri95 p.4 a(bjj*yzw(age for an air–glass $(n=1.52)$ surface? $\theta_{p}$    $^{\circ}\,$

  What is Brewster’s angle for a diamond submerb71)+ajtwdqy ,c.sf hu i7ue. ged in water if the light is hitting taq u 1uwh+t.fe dc7yjb,.s)i7 he diamond $(n=2.42)$ while traveling in the water? $\theta_{p}$    $^{\circ}\,$

  Two Polaroids are aligned so that the light passijvx b,wqs :g 6 kf.govct67f.7 8zx,sang through them is a maximum. At what angle should one of them be placed so that the intensity is subsequently reduced by half? 7:. zxcbv7 s6kavg8, .tfoq,gxf6js w   $^{\circ}\,$

  At what angle should the axes of two Pole6lhu)o*93 t*b5ahoaoj v) ro aroids be placed so as to reduce the intensity of the incidee*oh vu)lj *5o) oaa3b96hrt ont unpolarized light to
(a) $\frac{1}{3}$ ,    $^{\circ}\,$
(b) $\frac{1}{10}$ ?    $^{\circ}\,$

  Two polarizers are oriente)3 ds.:6 2bbtsbm3vbmx g tnp9d 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 oew x*x1rl0uy/riented 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 s,j84t4h ,yb1hyo ng- ba/no5p bd a0nsurface of water for light coming from beneath the surface? Compare to the angle for total internal reflection, and to Brewster’s angle from above the surfa,4b ndpbg01,y8b oys h5jh-aatno4n/ce.
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 sheets, each ok/cey.zx 3/3mqyk uh4s:pr c( f whose axis makes apekh3. sccz3yxyr /mq :k( u/4 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam?    $I_0$

  Light of wavelength rj;hntls z s3:q ap(1a10dx(o$ 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 mountain/.zf x)5dfdkt2fi a*i:pw1 eds or airplanes can interfere with the direct signal from the staedxizw f2/ tp5)1*dkf.da :iftion.
(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 glr9ch .pg7g5 jy o7pl)v3b rn(rating with (y hg.9 prr7oljbclnp )v7g 35$ 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 narron rbr q8pu(oeh6u7* m;6 2ihrfw slits 0.60 mm apart. The screen is 1.70 m away. A second source of unknown wavelength produces its second-order roh mr;r*6 e 8n76b2ifhpu(qu 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 identical antetn/u9rnuege 4 5/3msn: e gn:ennae at the same r uen9/4:e5e u/ms t3 engng:nelevation but 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 w4,fv5s) atme ba dpe 2c,a,tr/histle of frequency 750 Hz. Ignoring reflections, estimate at what angle(s) it is not p t),at,4,a v /rbefma5p2scdeossible to hear the whistle clearly on the playground outside the doorway.    $^{\circ}\,$ either side of the normal.

If parallel light falls on areyu9j28ex g g)6(yav single slit of width D at a 30$^{\circ}\,$ angle to the normal, describe the diffraction pattern.

  The wings of a certain beetle have a series of parallel lines acxek55in;i- p yross them. When normally incident 460-nm lighnp5y ;-ii ke5xt 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 must a grazte2c:+24x o jgyll l9mo ,x-gting have if there is to be no second-order spectrum for any visible wavelength? 2,lzcol4 j +t:gyeml-x92 o xg  $ lines/cm$

Show that the second- and third-order spectra of vz iriohg8ff3wh ,5+9white light produced by a diffraction grating always overlap. What wavelengths overlap e8h fr5 zv+wi3ih f9g,oxactly?

  When yellow sodium light8 ukde/zna.m/ , $\lambda\;=\;$ 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 gqhec3qjo2k4k.0:l e arating with and the pattern is viewed on a screen 2.5 m from the grating. The incident lik.okl0q23h a ejqce4 :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 clear material if a minimum of n ic(:w/(zzyefb (ij7 150 nm thickness of it, when laid on glass, is needed to reduce reflection to nearly zero when light of 600 nm is inn/(f (zy(bi 7zcwije: cident normally upon it? Do you have a choice for an answer?

  Monochromatic light of variable wavelength is incxh ggn2 182vtgident normally on a thin sheet of plastic fit8hv12x gg 2nglm 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 ;mhi)g1hey s lxds7;l tvh3xgi -5w* 6thickness needed 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 for the air layer bev*fazbfl9 uru+ 52v p(tween two flat glass surfaces if the glass is to appearuvl2 bva +u(f5* rzf9p dark when 640-nm light is incident normally?    nm
What if the glass is to appear bright?    nm

Suppose you viewed the light transmitted through a thin film layered on a fla onpdlj)w/y6/fzgx -:t piece of glass. Draw a diagram, similar to Fig. 24–30 or 24–36,) l/gpdyxw:n /f-oz6j 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 Sun when light reflectinga0((pna e9mc e off a smooth lake is polarize0n cm(ap9ae( ed most strongly?    $^{\circ}\,$

  At what angle should the axes of two Polaroids be placed so as 30hga( 5 an2mrbm-sba to reduce the intensity of the ina bnm20-g 5s (ahmbar3cident unpolarized light by an additional factor (after the first Polaroid cuts it in half) of
(a) 4,    $^{\circ}\,$
(b) 10,    $^{\circ}\,$
(c) 100?    $^{\circ}\,$

  Unpolarized light falls on two polarizer sheets wa.vtb0 xvd0*:esvth/hose transmission axes are at right angles. A third polarizer i*.xtsvv0ta0v/:e hbd s 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 axes vertical, at 30fed3 mhey/ 86o$^{\circ}\,$ 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 the Mfje 1il*x6y0 ioon, which is approximately 380,000 km from the Earth.1 jyfl0*ix i6e 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 are eaei ww )(j;a6te 5oxq)hch 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 ; b;m9d6rnir))zm sct $(n=1.34)$ 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 wavesma xo90xo0s7c jq/ r1s in phase with each other. They are located at pointaocjx71/qrx9 0som s0s $S_1$ 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 s)sq2r a3(mybt 6, amynm and 650 nm, enters a silicate flint glass equilateral prism (Fig. 24m y)(,r mayst2qbs3a6–58).
(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 7luz: h y.b5easurface 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