TEST-05 TOPIC: OPTICS COMPLETE

Transcription

1 Q. A boy s walkng under an nclned mrror at a constant velocty V m/s along the x-axs as shown n fgure. If the mrror s nclned at an angle wth the horzontal then what s the velocty of the mage? Y V sn + V cos j V cos + V sn j V V sn + V cos j V cos + V sn j Q. A telescope has focal length of objectve and eyepece as 00 cm and 5 cm respectvely. What s the value of magnfyng power? Q. A plane mrror s Inclned at an angle = 0 wth the horzontal surface. A partcle P s projected wth velocty V = 0 m/s as shown n fgure. Tme when the mage wll come momentarly at rest w.r.t. to the partcle 0 60 P V TEST-05 TPIC: PTICS CMPLETE X Q.4 The magnfcaton produced by an astronomcal telescope for normal adjustment s 0 and the length of telescope s.m. The magnfcaton when mage s formed at least dstance of dstnct vson (D = 5 cm) s Q.5 A telescope of objectve lens dameter m uses lght of wavelength 5000 Å for vewng stars. The mum angular separaton between two stars whose mage s just resolved by telescope rad rad rad 5 0 rad Q.6 An astronomcal telescope has a convergng eyepece of focal lengths 5 cm and objectve of focal lengths 80 cm. When the fnal mage s formed at the least dstance of dstnct vson (5 cm), the separaton between the two lenses s cm 80.0 cm 8.. cm 85.0 cm Q.7 The magnfcaton produced by an astronomcal telescope for normal adjustment s 0 and the length of telescope s.m. The magnfcaton when mage s formed at least dstance of dstnct vson s Q.8 In a mcroscope the focal lengths of two lenses are.5 cm and 6.5 cm. If an object s placed at cm from objectve and fnal mage s formed at 5 cm from eye lens, the dstance between two lenses s - 6 cm 7.75 cm 9.5 cm cm Q.9 Magnfcaton of a compound mcroscope s 0. Focal length of eye - pece s 5 cm and mage s formed at a dstance of 5 cm from eye - pece. The magnfcaton of objectve lens s Q.0 The mrror of length makes 0 revolutons per ute about the axs crossng ts md pont and perpendcular to the plane of the fgure There s a lght source n pont A and an observer at pont of the crcle of radus drawn around centre (A = 90º) What s the proporton f the observer frst sees the lght source when the angle of mrror = 5º? Page of 6

2 A lght at a dstance above the sphere. The area of the shadow on the plane s S Q. Two plane mrror whch are perpendcular are forg two sdes of a vessel flled wth lqud of refractve ndex =.5. After all possble refracton and reflecton, fnd the devaton () n ray A 0º 4 Q.4 A body of mass 00g s ted to one end of sprng of constant 0 N/m. The dstance between pole of mrror and mean poston of the body s 0cm. The focal length of convex mrror s 0cm. ne of the ampltudes of vbraton of the mage s - =.5 90º = 0º = 80º = 90º we can't fnd out devaton as other two angles A and n fgure s not gven Q. If an object moves towards a plane mrror wth a speed v at an angle to the perpendcular to the plane of the mrror, fnd the relatve velocty between the object and the mage - y v 0 v v v v cos v sn Q. An opaque sphere of radus les on a horzontal plane. n the perpendcular through the pont of contact there s a pont source of I x 0 cm 0cm 0.67 cm f =0cm 50 cm 0. cm Q.5 A concave mrror s placed on a horzontal table wth ts axs drected vertcally upwards. Let be the pole of the mrror and C ts centre of curvature. A pont object s placed at C. It has a real mage, also located at C. If the mrror s now flled wth water, the mage wll be- eal and wll reman at C eal and located at a pont between C and Vrtual and located at a pont between C and eal and located at a pont between C and Q.6 A small pece of wre bent nto an L shape wth uprght and horzontal portons of equal lengths, s placed wth the horzontal porton along the axs of the concave mrror whose radus of curvature s 0 cm. If the bend s 0 cm from the Page of 6

3 pole of the mrror, then the rato of the lengths of the mages of the uprght and horzontal portons of the wre s - : : : : Q.7 A real nverted mage n a concave mrror s represented by: (u, v, f are coordnates) v/f + + v/f + u/f u/f Q.8 An object s placed nfront of a convex mrror at a dstance of 50 cm. A plane mrror s ntroduced coverng the lower half of the convex mrror. If the dstance between the object and plane mrror s 0 cm, t s found that there s no parallax between the mages formed by two mrrors. adus of curvature of mrror wll be cm 5 cm cm 8 cm Q.9 A slab of glass, of thckness 6 cm and refractve ndex.5, s placed n front of a concave mrror, the faces of the slab beng perpendcular to the prncpal axs of the mrror. If the radus of curvature of the mrror s 40 cm and the reflected mage concdes wth the object, then the dstance of the object from the mrror s - 0 cm 4 cm v/f cm 8 cm Q.0 A glass rod of rectangular cross-secton s bent nto the shape shows n the Fg. (a). A parallel beam of lght falls perpendcularly on the flat surface A. Detere the mum value of the rato /d for whch all lght enterng the glass through surface A wll emerge from the glass through surface. The ndex of refracton of the glass s u/f d d d A Fg. (a) = d = 5 d = 4 = 7 Q. Two transparent slabs are of equal length. ne s made of a materal A of.i..5 and the other of materals and C, the rato of thckness beng :. The.I. of C s.6. When lght passes through them, the two slabs have the same number of waves. The.I. of s A C Q. A ray of lght travels from a medum of refractve ndex to ar. Its angle of ncdence n the medum s, measured from the normal to the boundary, and ts angle of devaton s. s plotted aganst whch of the followng best represents the resultng curve - / / / / Q. Crtcal angle for lght gong from medum () to () s. The speed of lght n medum () s v, then speed n medum () s - v ( cos ) v / sn v / cos v ( sn ) Q. 4 A prsm of refractve ndex and angle A s placed n the mum devaton poston. If the Page of 6

4 /////////////// /// angle of mum devaton s A, then the value of A n terms of s - sn cos sn cos Q.5 Lght s ncdent normally on face A of a prsm as shown n fgure. A lqud of refractve ndex s placed on face AC of the prsm. The prsm s made of glass of refractve ndex /. The lmts of for whch total nternal reflecton takes place on face AC s : A Lqud C 0º 0º > 90º < 4 > < Q.6 A prsm havng an apex angle 4º and refractve ndex.5 s located n front of a vertcal plane mrror as shown n fgure. Through what total angle s the ray devated after reflecton from mrror 4º shown n Fg. Where an object should be placed n the medum so that a real mage s formed n medum at the same dstance? P I x x Q.9 A convex lens of focal length 0 cm s cut nto two equal parts so as to obtan two plano-convex lenses as shown n fg.. The two parts are then put n contact as shown n fg.. What s the focal length of combnaton zero 0 cm 5 cm 0 cm Q.0 Focal length of the shown plano-convex lens s 5 cm. Plane surface of the lens s slvered. An object s kept on the prncpal axs of the lens at a dstance 0 cm. Image of the object wll form at. 76º 4 78º º Q.7 A gven ray of lght suffers mum devaton n an equlateral prsm P. Addtonal prsms Q and of dentcal shape and materal are now added to P, as shown n the fgure. The ray wll suffer - P Q () greater devaton () same devaton () no devaton (4) total nternal reflecton Q.8 A sphercal surface of radus separates two medum of refractve ndces and, as bject 0cm 60 cm, left 60 cm, rght cm, left 0 cm, rght Q. The relaton between n and n f the behavour of lght ray s as shown n the fg. s - n n Lens Page 4 of 6

5 n > n n >> n n > n n = n Q. A dvergng lens, focal length f = 0 cm s separated by 5 cm from a convergng mrror, focal length f = 0 cm. Where should an object be placed from the lens so that a real mage s formed at the object tself? 0 cm 60 cm 0 cm 40 cm Q. The dagram shows a concavo-convex lens. What s the condton on the refractve ndces so that the lens s dvergng. I of lens s < + > + > ( ) None of these Q.4 A convex lens s made up of three dfferent materals as shown n the fgure. For a pont object placed on ts axs, the number of mages formed are - () () () 4 (4) 5 Q.5 Interference frnges were produced n Young's double slt experment usng lght of wavelength 5000 Å. When flm of thckness.5 0 cm was placed over one slt, the frnge pattern shfts by a dstance equal to 0 frnge wdth. The refractve ndex of flm materal s Q.6 In YDSE f a slab whose refractve ndex can be vared s placed n front of one of the slts. Then the varaton of resultant ntensty at md pont of screen wth wll be best represented by ( s greater than or equal to ) = = = = Q.7 An unpolarsed beam of ntensty s ncdent on a par of ncol prsms makng an angle of 60º wth each other. The ntensty of lght emergng from the par s - I 0 I 0 I Q.8 Two sources gve nterference pattern whch s observed on a screen, D dstance apart from the sources. The frnge wdth s. If the dstance D s now doubled, then the frnge wdth wll become - 4 remans same Q.9 In an nterference experment, thrd brght frnge s obtaned on the screen wth a lght of 700 nm. What should be the wavelength of lght source n order to obtan 5 th brght frnge at the same pont - 40 nm 500 nm 750 nm 60 nm Q.40 In young's double slt experment, a coherent parallel stream of electrons, accelerated by a potental dfference V = 45.5 volt s used to obtan nterference pattern. If slts are separated by a dstance d = 66. m and dstance of screen s D = 09. cm from plane of slts, calculate dstance between two consecutve maxma on the screen : [mass of electron = 9. 0 kg Plank constant h = J-s] 6 m 9 m m m Page 5 of 6

6 Q.4 Frnge wdth observed n the Young's double slt experment s. If the frequency of the source s doubled, the frnge wdth wll reman become / become reman / Q.4 In Young's experment, the rato of maxmum and mum ntenstes n the frnge system s 9 :. The rato of ampltudes of coherent sources s 9 : : : : Q.4 When unpolarsed lght beam s ncdent from ar onto glass at polarsng angle - eflected lght s polarsed 00 percent eflected & refracted beams are partally polarzed eflected & refracted beams are completely polarsed efracted lght s polarsed 00 percent Q.44 If the ntenstes of the two nterferng beams n Young's double slt experment be I and I, then the contrast between the maxmum and mum ntensty s good when I s much greater than I I s much smaller than I Ether I or I s zero I = I Q.45 The maxmum number of possble nterference maxma for slt-separaton equal to twce the wavelength n Young's double-slt experment s three nfnte fve zero Page 6 of 6