# Practice Test

Q1) A ray of light falls spherical on mirror normally, the values of angle of incidence 'i' and angle of reflection 'r' respectively are Show Answer

Q2) In an experiment to find the focal length of a concave mirror, an object is placed at a distance of 40 cm from it and forms image at 24 cm from the mirror, then the focal length is Show Answer

Q3) An object is placed at a distance of 25 cm from a spherical mirror, its image is formed behind the mirror at a distance of 5 cm. The focal length and type of mirror is Show Answer

Q4) A 4.5 cm needle is placed 12 cm away from a convex mirror of focal length 15 cm. Locate the image of the needle from the mirror. Show Answer

Q5) An object is at a distance of 10 cm from a concave mirror and the image of the object is at a distance of 30 m from the mirror on the same side as that of the object. The radius of curvature of the concave mirror is Show Answer

Q6) The lens formula with normal notation is given by Show Answer

Q7) The lens marker's equation is given by Show Answer

Q8) A concave lens has radii of curvatures of 20 cm and 30 cm respectively. If the refractive index of the material of lens is 1.6, its focal length is given by Show Answer

Q9) The magnifying power of simple microscope, when image is formed at DDV, is ( where f is its focal length) Show Answer

Q10) When the final image is formed at infinity, the magnifying power of compound microscope is ( using new cartesian sign conventions) Show Answer

Q11) Which of the following is NOT an expression for magnifying power of compound microscope when final image is formed at distance of distinct vision ? ( using new cartesian sign conventions) Show Answer

Q12) The length (L) of compound microscope when final image is formed at D.D.V is given by Show Answer

Q13) Two thin lenses of power +12 D and -2D are combined together. Their equivalent focal length is Show Answer

Q14) The length (L) of the astronomical telescope, for normal adjustment is Show Answer

Q15) Magnifying power of an astronomical telescope is M.P. If the focal length of the eye-piece is doubled, then its magnifying power will be Show Answer

Q16) Magnification of simple microscope when image at infinity is given by Show Answer

Q17) The radius of curvature of each surface of a biconcave lens made up of glass of refractive index 1.5 is 30 cm. The focal length of the lens is Show Answer

Q18) A convex lens of focal length f produces a real image 3 times as that of size of the object, the distance between the object and the lens is Show Answer

Q19) Two thin lenses, one convex of focal length 10 cm and other concave lens are kept in contact to form a composite lens of focal length 130 cm. If the combination acts as a converging lens then the focal length of second lens is Show Answer

Q20) Light is a form of energy which travels as Show Answer

Q21) The straight path of the light is called Show Answer

Q22) The study of light without considering diffraction is called Show Answer

Q23) The bending of light round the edge of an obstacle is called Show Answer

Q24) Light from point source travels in a straight line with very high speed hence Show Answer

Q25) Choose the COORECT statement. Show Answer

Q26) The geometrical centre of surface of spherical mirror is called its Show Answer

Q27) The principal axis of spherical mirror passes through Show Answer

Q28) After reflection, the parallel beam of light appears to come from a point then the type of mirror is Show Answer

Q29) Which spherical mirror is divergent ? Show Answer

Q30) For the spherical mirrors, the relation between focal length (f) and radius of curvature ( R ) is given by Show Answer

Q31) A convex mirror gives an image which is Show Answer

Q32) A concave mirror produces a virtual image when the object is Show Answer

Q33) An object is placed at a distance equal to focal length of a convex mirror. If the focal length of a miror be f, then the distance image from the pole of the mirror is Show Answer

Q34) A concave mirror is placed on a horizontal table with its axis vertically upwards. Let O be the pole of the mirror and C be the centre of curvature. A point object placed at C, forms real image at C. If the mirror is now filled with water, the image will be Show Answer

Q35) The field of view is maximum for Show Answer

Q36) For concave mirror, if the object is at the focus point F, the image is Show Answer

Q37) According to new cartesian sign convention, the distances measured Show Answer

Q38) A virtual image larger than the object can be produced by Show Answer

Q39) A convex mirror may be used for all but it can NOT be used for Show Answer

Q40) Given a point source of light, which of the following can produce a parallel beam of light ? Show Answer

Q41) A virtual object is placed between the pole and principal focus of a convex mirror produces an image which is Show Answer

Q42) While deriving expression for refraction at single curved surface, the object is considered as Show Answer

Q43) The focal length of a lens depends upon Show Answer

Q44) The focal length of concave lens, according to new cartesian sign conventions is Show Answer

Q45) According to new cartesian sign convention, all the distances are measured from Show Answer

Q46) A diverging lens may NOT have Show Answer

Q47) A concave lens of focal length f produces an image 1/4 of the size of the object, the object should be kept at ____ from the lens. Show Answer

Q48) An object is kept at 0.2 m from a convex lens of focal length 0.15 m. The position of the image is Show Answer

Q49) A beam of light is incident on a convex lens parallel to its principal axis. As one moves away from the optical centre of the lens on its other side, the intensity of light Show Answer

Q50) A screen is placed 90 cm from an object. The image of the object on the screen is formed by a convex lens at two different locations seperated by 20 cm. The focal length of the lens is Show Answer

Q51) A single lens which will form the image of a given object at the same point as is formed by the combination of two or more thin lenses, is called as Show Answer

Q52) Two thin lenses may be combined so as to Show Answer

Q53) Two thin covering lenses of focal length 15 cm and 30 cm are held in contact with each other. The focal length of the combination is Show Answer

Q54) The least distance of distinct vision for a young adult with normal vision is Show Answer

Q55) A normal eye is unable to see objects at a distance less than distance of distinct vision. It is because Show Answer

Q56) The clarity of image formed on retina of eye depends on the Show Answer

Q57) A convex lens of short focal length held very close to the eye, to observe minute objects clearly is called as Show Answer

Q58) The magnifying power of simple microscope is maximum when image is formed at Show Answer

Q59) When a convex lens of 2.5 cm focal length is used as a magnifying glass, normal eye can see an object clearly at a distance of 25 cm. The magnifying power of the instrument is Show Answer

Q60) The magnifying power of simple microscope is 6 when the image is formed at distance of distinct vision (25 cm) from its optical centre. The focal power of the simple microscope in dioptre is Show Answer

Q61) The compound microscope is used to see Show Answer

Q62) Compound microscope has an object of comparitively. Show Answer

Q63) Compound microscope is NOT used in Show Answer

Q64) In a compound microscope, the intermediate image is Show Answer

Q65) The focal length of the eye piece of compound microscope is Show Answer

Q66) A compound microscope has a magnifying power of 35. Assume that the final image is formed at DDV (25 cm). If the focal length of eye piece is 8 cm, the magnification produced by objective is Show Answer

Q67) The objects which are at large distance as compared to the focal length of the lens ( greater than 10 x f) are reffered as Show Answer

Q68) The objective of astronomical telescope has Show Answer

Q69) The intermediate image formed by the objective is Show Answer

Q70) To see terrestrial objects, the final image must be Show Answer

Q71) When a ______ is introduced between objective and eye piece of telescope then it is used as a terrestrial telescope. Show Answer

Q72) When astronomical telescope is adjusted for normal adjustment the final image is formed at Show Answer

Q73) The focal length of objective and eye piece of astronomical telescope are 2 m and 5 cm respectively. The magnifying power of telescope when final image is formed at infinity is Show Answer

Q74) The objective of reflecting telescope is Show Answer

Q75) A ______ is fixed at focal point of the objective, which reflects the collected rays to eye piece. Show Answer

Q76) Out of the following optical instruments which one is independent of chromatic and spherical aberrations Show Answer

Q77) A fly is sitting on the objective of a telescope pointed to the moon. What is the effect in the photograph of the moon taken through the telescope ? Show Answer

Q78) The distance between an object and the screen is 75 cm. When a convex lens of focal length 12 cm is placed in between the object and the screen,magnification of real image formed can be ( magnitude only) Show Answer

Q79) Ray optics is valid, when characteristic dimensions are Show Answer

Q80) A diminished virtual image can be produced only with Show Answer

Q81) A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen, then Show Answer

Q82) The lens will be visible in vacuum when the refractive index of the lens is Show Answer

Q83) A lens behaves as a converging lens in air and a diverging lens in water. The refractive index of the material is ( refractive index of water is 1.33) Show Answer

Q84) A person using a lens as a simple microscope sees an Show Answer

Q85) When we view object of height 15 m with a telescope of magnifying power 10. To him, the object appears Show Answer

Q86) The magnifying power of simple microscope is Show Answer

Q87) An optical instrument, in general, extends our range of vision by Show Answer

Q88) In astronomical telescope, which of the following statement is NOT applicable ? Show Answer

Q89) For observing fainter distant objects and for high resolving power following instrument telescope is used Show Answer

Q90) An astronomical telescope of ten fold angular magnification has length of 44 cm. The focal length of objective is Show Answer

Q91) When two thin lenses are kept in contact, the focal length of the combination is Show Answer

Q92) In case of reflection from curved surface Show Answer

Q93) If the object is placed at A and the image is formed at B when the rays are refracted through a convex lens. The positions of A and B are changeable, such pair of points is called Show Answer

Q94) The wavelength range of visible light is Show Answer

Q95) When an object is kept in front of a convex lens, the distance between it and the real image is 54 cm. If the magnification produced is 2, the focal length of the lens is Show Answer

Q96) A vessel is filled with two different liquids which do not mix. One is 40 cm deep and has R. I. 1.6 and other is 30 cm deep and has R. I. 1.5. The apparent depth of vessel when viewed normally is Show Answer

Q97) An air bubble inside a cubical block of glass of side 4.5 cm seems to be at 2 cm from one face and 1 cm from the other face opposite to first when viewed normally. The real distance of bubble is (from first face) Show Answer

Q98) If the R. I. of water is 4/3 and that of glass slab is 5/3, then the critical angle for the ray coming from glass to water is Show Answer

Q99) A ray of light enters from a denser medium into rarer medium. The speed of light in rarer being twice that in the denser. The angular range in which the fish just below the surface of denser can see the objects outside is Show Answer

Q100) Critical angle of light passing from glass to air is minimum for Show Answer

Q101) A ray of light is incident from denser to rarer. The reflected and refracted ray are at right angle to each other. If r is the angle of reflection and r' is the angle of refraction, then critical angle is Show Answer

Q102) R. I. of water is 4/3 and a fish inside the water judges the height of the bird above the water level as 200 m, then the actual height above the water level is Show Answer

Q103) A ray of light is incident from a small source 4 m below the surface of water of R. I. 5/3. In order to cut all the light coming out of water the minimum diameter of disc placed on water surface is Show Answer

Q104) Just before the time of sunset, the sun appears to be elliptical because Show Answer

Q105) The distance of object when a concave mirror produces an image of magnification m Show Answer

Q106) The distance of object when a convex produce an image of magnification m Show Answer

Q107) The image formed by a convex mirror of focal length 30 cm is one quarter of the size of object. The distance of object from the mirror is Show Answer

Q108) An object is placed at the focus of concave mirror of focal length 20 cm. The distance of the image is Show Answer

Q109) A concave mirror of focal length f in air is used in a transparent liquid of R. I. 2 for producing an image of the object. What is its new focal length? Show Answer

Q110) A lens with + P power is immersed in water. Its power Show Answer

Q111) A convex lens produces a real image m times the size of the object. The distance of the object is Show Answer

Q112) A convex lens of focal length f produces a virtual image n times of the object. The distance of object is Show Answer

Q113) The distance between the object and real image formed by a convex lens is D. If the the magnification is m, then focal length f is Show Answer

Q114) In the displacement method if the distance between object and screen is D, the real images are formed corresponding to two positions of the lens separated by 'd'. The ratio of sizes of the two images is Show Answer

Q115) A concave and convex lens have same focal length of 20 cm and are put in contact. The combination is used to view an object of 5 cm length kept at 20 cm from the lens combination. As compared to object the image will be Show Answer

Q116) The resolution limit of eye is one minute. At a distance x km from the eye two objects are situated with 3 m separation. For the two objects to be just resolved the value of x for the eye is Show Answer

Q117) A plano - convex lens of R. I. 1.5 silvered at the convex surface behaves as a concave mirror of focal length 20 cm. What is the radius of curvature of curved surface? Show Answer

Q118) An empty spherical flask of diameter 30 cm is placed in water of R. I. 4/3. A parallel beam of light strikes the flask. Where does it get focused when observed from within the flask? Show Answer

Q119) A plano-convex lens has a focal length of 20 cm and R. I. 1.5. What is its radius of curvature? Show Answer

Q120) The radius of curvature of each surface of a double convex lens is 20 cm and R. I. of its material is 3/2. The lens is cut into two equal parts along a line perpendicular to the principal axis. What is the focal length of either of the new lens? Show Answer

Q121) The radius of curvature of each surface of a double convex lens is 20 cm and R. I. of its material is 3/2. The lens is cut into two equal parts along a line perpendicular to the principal axis. What is the focal length of each part? Show Answer

Q122) When a convex lens of focal length 10 cm is placed in contact with a concave lens, the power of combination is + 5 D. What will be the power when the lenses are separated by 10 cm in air? Show Answer

Q123) A thin converging lens forms the image of a certain object magnified m times. The magnification becomes n, when lens is moved nearer to object by a distance x. Focal length of the lens is Show Answer

Q124) In displacement method if D is the distance of the object and screen and 'd' is the separation between the two positions of the lens, then the ratio of magnified image to that of the object is Show Answer

Q125) A thin lens has a focal length f and its aperture has diameter d. It forms an image of intensity I, the central part up to diameter d/2 is blocked by an opaque paper. The focal length and the image intensity will change to Show Answer

Q126) A spherical mirror forms an erect image three times the size of the object. If the distance between the object and the image is 100 cm the focal length of the mirror is Show Answer

Q127) A square wire of side 6.0 cm is placed 25.0 cm away from a concave mirror of focal length 10.0 cm. The area enclosed by the image of the wire, whose center is on the principal axis, is Show Answer

Q128) The focal length of a concave mirror is f and the distance from the object to the principal focus is x, then ratio of the size of the image to the size of the object is Show Answer

Q129) The dispersive powers of the materials of the two lenses are in the ratio 4/3. If the achromatic combination of these two lenses in contact is a convex lens of focal length 60.0 cm, then focal length of component lenses is Show Answer

Q130) Indicate the colour which travels through glass with the minimum speed Show Answer

Q131) In an achromatic combination of prisms the net deviation produced when the prisms are of the same material, is Show Answer

Q132) Two lenses of focal lengths + 10 and -15 cm are in contact. For zero chromatic aberration, the ratio of dispersive powers is Show Answer

Q133) A convex lens has mean focal length 30 cm and the dispersive power of the material is 40. The longitudinal chromatic aberration for the object at infinity is Show Answer

Q134) A parallel beam of white light falls on a convex lens. Images of blue, yellow and red light are formed on the other side of the lens at a distance 20 cm, 20.5 cm and 21.4 cm respectively. The dispersive powers of the material of the lens will be Show Answer

Q135) For a myopic eye, the far point is at 250 cm. To correct this defect, the nature of the lens and its focal length will be Show Answer

Q136) A person cannot see objects clearly beyond 50 cm. The power of the lens to correct his vision is Show Answer

Q137) A far-sighted person cannot focus clearly on an object closer than 120 cm. If he wants to read a book at a distance 40 cm, he requires a lens of Show Answer

Q138) The far point of the myopic eye is 200 cm. The power of the lens required to correct this defect is Show Answer

Q139) A person can see objects lying between 50 cm and 100 cm. What power of lens will be use for reading a book? (Distance of L.D.V. is 25 cm) Show Answer

Q140) A myopic person can see things clearly lying between 8 cm and 100 cm from his eyes. The lens which enables his to see the moon should have a focal length of Show Answer

Q141) A convex lens of 3 cm focal length is used as a simple microscope by an eye with distance of least distinct vision as 30 cm. What is the magnifying power? Show Answer

Q142) The objective and eye-piece of a compound microscope have focal length 0.4 cm and 2.5 cm respectively. If the lengths of the tube is 16 cm and distance of distinct vision is 25 cm, the magnifying power of microscope giving final image at infinity is Show Answer

Q143) Resolving power of a microscope can be increased if we use Show Answer

Q144) The distance between objective and eye-piece for astronomical telescope when adjusted for parallel rays is 80 cm, the magnification is 15. The focal lengths of two lenses are Show Answer

Q145) The powers of the lenses of a telescope are 0.5 and 20 dioptres. Its magnifying power is Show Answer

Q146) The objective and eye-lens of a telescope have focal lengths 30 cm and 3 cm. It is focused on a scale 2 metres away. The distance between the two lenses for normal vision is Show Answer

Q147) A small object is placed at a distance of 3.6 cm from a magnifier of focal length 4.0 cm. The linear magnification is Show Answer

Q148) A small object is placed at a distance of 3.6 cm from a magnifier of focal length 4.0 cm. The angular magnification is nearly (D = 25 cm) Show Answer

Q149) A compound microscope is used to enlarge an object kept at a distance of 0.03 m from the objective which consists of several convex lenses in contact and has the focal length 0.02 m. The image formed by objective is at Show Answer

Q150) A locality is photographed from an aeroplane flying at a height of 3 km with a camera whose focal length is 1 m. The ratio of the linear size of the image to the size of the object is nearly Show Answer

Q151) The resolution limit of eye is 1 minute. At a distance X km from the eye two person stand with a lateral separation of 3 m. For the two persons to be just resolved by eye, X should be Show Answer

Q152) A person looks at two different trees in an open space. First tree is 2 meters high at a distance of 50 meters and second tree is 4 meters high at a distance of 200 meters respectively from the eye. The apparent sizes are Show Answer

Q153) The maximum value of index of refraction of a material of a prism which allows the passage of light through it when the refracting angle of prism is A, is Show Answer

Q154) A rod of length 10.0 cm lies along the principal axis of a concave mirror of focal length in such a way that the end closer to the pole is 20.0 cm away from it. The length of the image is Show Answer

Q155) A luminous object is placed at a distance of 30 cm from a convex lens of focal length 20 cm. On the other side of lens, at what distance from the lens, a convex mirror of radius of curvature 10 cm be placed in order to have an inverted image of the object coincident with it? Show Answer

Q156) A convex lens has different media on its two sides. Its first focal length is 10 cm. An object is placed at a distance of 15 cm from the first principal focus. The lens produces its image on the other side at a distance of 20 cm from the second principal focus. The second focal length is Show Answer

Q157) A convex lens of focal length f is placed some-where in between the object and a screen. The distance between object and screen is x. If magnification produced is m, the focal length of the lens is Show Answer

Q158) The principal section of a glass prism is an isosceles triangle ABC with AB = AC. The face AC is silvered. A ray is incident normally on face AB and after two reflection, it emerges from the face BC, per-pendicular to it. The angle BAC of the prism is Show Answer

Q159) A magnifying glass is made of combination of convex lens of power + 20 D and concave lens of power 4 D. If the distance of distinct vision of eye is 25.0 cm, the magnifying power of the lens, when image is formed at infinity is Show Answer

Q160) An angular magnification of 30 is desired using an objective of focal length 1.25 cm and eye piece of focal length 5.0 cm. To set up the microscope the distance between the lenses is approximately Show Answer

Q161) A simple two lens telescope has an objective of focal length 2.5 cm. The telescope is pointed at an object at a very large distance which subtends an angle of 1 milliradian on the naked eye. The eye piece is so adjusted that final image is formed at infinity. The size of the real image formed by objective is Show Answer

Q162) A small telescope has an object lens of focal length 140 cm and eye piece of focal length 5.0 cm. The telescope is used to view a 100 m tall tower 3 km away. The height of the image of the tower formed by objective lens is Show Answer

Q163) A man stands on a vertical tower of height 20 m. Calculate the distance upto which he will be able to see on the surface of earth. Neglect height of man. Radius of earth = 6400 km. Show Answer

Q164) A rectangular block of glass is placed on a printed page lying on a horizontal plane. Find the minimum value of refractive index of glass for which the letters on the page are not visible from any of the vertical faces of the block Show Answer

Q165) The distance between two point sources of light is 24 cm. Where should a convergent lens of focal length 9 cm be placed between them to obtain images of both sources at the same point? Show Answer

Q166) One face of rectangular glass slab of thickness 6 cm is silvered. An object is held 8 cm in front of the front face forms an image 10 cm behind the silvered face. What is refractive index of glass? Show Answer

Q167) The focal length of a lens in a camera, marked f : 2.8 is 8 cm. What is diameter of lens? Show Answer

Q168) If the correct time of exposure is 1/200 s with a lens marked f : 2.8, what would be correct time of exposure with a lens marked f : 5.6? Show Answer

Q169) The area of moon's image produced by a convex lens is proportional to focal length as Show Answer

Q170) A glass sphere with center O is shown in fig. AOB and COD are two diameters at right angle to each other. A ray parallel to AOB strikes the sphere at P. Find the deviation of ray as it emerges out of the sphere. Show Answer

Q171) An object is placed 20 cm the left of a convex lens of focal length 10 cm. If a concave mirror of focal length 5 cm is placed 30 cm to the right of the lens, find the magnification Show Answer

Q172) A plano-convex lens when silvered on the plane side behaves like a concave mirror of focal length 30 cm. When silvered on convex side, it behaves like a concave mirror of focal length 10 cm. The refractive index of material is Show Answer

Q173) A point object is placed on the principal axis of convex lens of focal length 20 cm at a distance 40 cm to the left on it. The diameter of the lens is 10 cm. If the eye is placed 60 cm to the right of the lens at a distance h below the principal axis, then max. value of h to see the image is Show Answer

Q174) The length of a microscope is 14 cm and its magnifying power is 25 for relaxed eye. The focal length of the eyes lens is 5 cm. The distance of the object from the objective is Show Answer

Q175) A student can distinctly see the object upto a distance 15 cm. He wants to see the black board at a distance of 3 m. Focal length and power of lens used respectively will be Show Answer

Q176) Two thin lenses of powers 12 D and - 2 D respectively are placed in contact, the power, focal length and nature respectively will be Show Answer

Q177) For a normal eye, the least distance of distinct vision is nearly Show Answer

Q178) For a myopic (short-sighted) eye, rays from far distant objects are brought to focus at a point Show Answer

Q179) Myopia occurs due to Show Answer

Q180) In hypermetropia i.e., long-sightedness, the person can Show Answer

Q181) To correct short-sightedness we require Show Answer

Q182) The long-sigtedness is corrected by using Show Answer

Q183) A man suffering from myopia can read a paper placed at 10 cm. What king of lens will he use for reading a book at 30 cm? Show Answer

Q184) The least distance of distinct vision for a person with defective eye-sight is 100 cm. What kind of lens will he use to see clearly an object at 25 cm? Show Answer

Q185) The interior of the eye is coated with transparent membrane and is provided with nerve, it is called Show Answer

Q186) A myopic person can see things clearly which lie between 8 cm and 100 cm from his eyes. His near point with the correcting lens will be Show Answer

Q187) A long-sighted person has a least-distance of distinct vision of 50 cm. He wants to reduce it to 25 cm. He should use a Show Answer

Q188) The ability of eye to focus on both near and far objects is called Show Answer

Q189) A cylindrical lens is required to correct Show Answer

Q190) Loss of the eye to focus on both far and near objects with advancing age is Show Answer

Q191) The eye is most sensitive, with ordinary intensity, for the colours Show Answer

Q192) A person with one eye has a Show Answer

Q193) In human eye the focusing is done by Show Answer

Q194) The resolving power of human eye is Show Answer

Q195) The light which enters the human eye experiences most of its refraction while passing through Show Answer

Q196) A person is 6 ft. tall. How tall must be a vertical mirror if he is able to see his entire length? Show Answer

Q197) Rainbow is formed due to combination of Show Answer

Q198) When a ray of light enters a glass slab, then Show Answer

Q199) Ratio of intensities of two waves is 9 : 1. If these waves are superimposed, what is ratio of max. and min. intensities? Show Answer

Q200) A doctor tells a patient to use spectacles with convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is power of combination? Show Answer

Q201) What is the minimum height of a plane mirror held vertically in front of a man of 6 ft. tall to see his entire image? Show Answer

Q202) A ray of light containing both red and blue light is incident on the refracting surface of a prism, then Show Answer

Q203) Optical fibre is based on Show Answer

Q204) Blue colour of sky is due to phenomenon of Show Answer

Q205) When light is passed through a prism, the colour which deviates least is Show Answer

Q206) Newton gave the corpuscle theory on the basis of Show Answer

Q207) A bulb is located on a wall. Its image is to be obtained on a parallel wall with the help of convex lens. The lens is placed at distance d ahead of second wall, then required focal length will be Show Answer

Q208) Which is having minimum wavelength? Show Answer

Q209) What is the cause of Greenhouse effect? Show Answer

Q210) Light propagates linearly due to its Show Answer

Q211) Brilliance of diamond is due to Show Answer

Q212) The Cauchy's dispersion formula is Show Answer

Q213) What is the path difference for destructive interference? Show Answer

Q214) Velocity of light is equal to Show Answer

Q215) Why sun has elliptical shape when it rises and sets? IT is due to Show Answer

Q216) If convex lens of focal length 80 cm and a concave lens of focal length 50 cm are combined together, what will be their resulting power? Show Answer

Q217) Why laser rays are used to measure long distance? Show Answer

Q218) A man is standing in a room of mirror. Man is able to see how many of his images in mirror when he is seeing at a corner? Show Answer

Q219) Optic fibres are related with Show Answer

Q220) Which of the following electromagnetic wave have highest wavelength? Show Answer

Q221) If an interference pattern has maximum and minimum intensity in the ratio of 36 : 1, then what will be the ratio of amplitude? Show Answer

Q222) A convex lens is dipped in a liquid of refractive index equal to the refractive index of the lens. Then its focal length will Show Answer

Q223) When a beam of light is used to determined the position of an object, the maximum accuracy is achieved if the light is Show Answer

Q224) An astronaut is looking down on earth's surface from a space shuttle at an altitude of 400 km. Assuming that the astronaut's pupil diameter is 5 mm and the wavelength of visible light is 500 nm, the astronaut will be able to receive linear objects of the size of about Show Answer

Q225) A convex lens is immersed in oil then refractive index depends upon Show Answer

Q226) Huygen's wave theory of light could not explain Show Answer

Q227) An optical illusion which occurs usually in deserts on hot summer days is based on Show Answer

Q228) Prof. C. V. Raman was awarded the Nobel prize for Show Answer

Q229) Which of the following does not change when light goes from one medium to another? Show Answer

Q230) For obtaining equal and same height, mirror should be Show Answer

Q231) The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image. Show Answer

Q232) A beam of light is composed of red and green rays and is incident obliquely at a point on face of a rectangular glass slab. When coming out of the opposite parallel face, the red and green rays emerge from Show Answer

Q233) A telescope has an objective lens of 10 cm diameter and is situated at a distance of one kilometer from two objects. The minimum distance between these two objects, which can be resolved by the telescope, when the mean wavelength of light is 5000 A, is of the order of Show Answer

Q234) In order to obtain a real image of magnification 2 using a converging lens of focal length 20 cm, where should be an object be placed? Show Answer

Q235) Assertion : A red object appears dark in the yellow light.
Reason : The red colour is scattered less. Show Answer

Q236) Assertion : At the first glance, the top surface of the Morpho butterfly's wing appears a beautiful blue-green. If the wing moves the colour changes.
Reason : Different pigments in the wing reflect light at different angles. Show Answer

Q237) Assertion : A famous painting was painted by not using brush strokes in the usual manner, but rather a myriad of small colour dots. In this painting changes as you move away.
Reason : The angular separation of adjacent dots changes with the distance from the painting. Show Answer

Q238) An endoscope is employed by a physician to view the internal parts of a body organ. It is based on the principle of Show Answer

Q239) When a compat disc is illuminated by a source of white light, coloured lines are observed. This is due to Show Answer

Q240) A point object is placed at the center of a glass sphere of radius 6 cm and refractive index 1.5. The distance of the virtual image from the surface of the sphere is Show Answer

Q241) The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 A is of order Show Answer

Q242) When exposed to sunlight thin films of oil on water often exhibit colours due to phenomenon of Show Answer

Q243) In case of linearly polarised light, the magnitude of electric vector Show Answer

Q244) In refraction, light waves are bent on passing from one medium to other, because in second medium Show Answer

Q245) A telescrope has objective lens of focal length 200 cm and eye piece of focal length 2 cm. If this telescope is used to see a 50 m tall building at a distance of 2 km what is height of image of building formed by objective lens? Show Answer

Q246) A stone thrown in still water, creates a circular wave patterns moving radially outwards. If r is distance measured from the center of pattern, the amplitude of wave varies is Show Answer

Q247) Which of the following statement is true? Show Answer

Q248) A convex and a concave lens, each having same focal length of 25 cm are put in contact to form a combination of lenses. The power in diapoters of the combination is Show Answer

Q249) A microscope is focused on a mark on a piece of paper. A slab of glass of thickness 3 cm and refractive index 1.5 is placed over the mark. How would be microscope be moved to get the mark focus again? Show Answer

Q250) A lens of power +2 diopters is placed in contact with a lens of power - 1 diopter. The combination will behave like Show Answer

Q251) A convex lens of crown glass (n = 1.525) will behave as a divergent lens if immersed in Show Answer

Q252) Magnifying power of a compound microscope is the ratio of angle formed by the final image to the angle formed by the object when Show Answer

Q253) A magnifying glass is to be used at the fixed object distance of 1 inch. If it is to produce an erect image magnified 5 times its focal length should be Show Answer

Q254) The penetration of light into the region of geometric shadow is called Show Answer

Q255) A convex mirror gives an image three times as large as the object placed at a distance of 20 cm from it. For the image to be real, the focal length should be Show Answer

Q256) A convex lens of focal length 0.5 m and concave lens of focal length 1 m are combined. The power of the resulting lens will be Show Answer

Q257) Fraunhofer spectrum is a Show Answer

Q258) The refractive index of water with respect to air is 4/3 and the refractive index of glass with respect to air is 3/2. The refractive index of water with respect of glass of Show Answer

Q259) A person cannot see objects clearly beyond 2.0 m. The power of lens required to correct his vision will be Show Answer

Q260) An astronomical telescope has an angular magnification of magnitude 4 for distance objects. The separation between the objective and the eye piece is 36 cm and final image is formed at infinity. The focal lengths of the objective and eye-piece are respectively. Show Answer

Q261) The unit of luminous efficiency of electric bulb is Show Answer

Q262) The interference phenomenon can take place Show Answer

Q263) The focal length of an equi-convex lens in air is equal to tither of its radii of curvature. The refractive index of the material of the lens is Show Answer

Q264) Lux is a unit of Show Answer

Q265) A watch shows time as 8:35 when seen through a mirror, time appears will be Show Answer

Q266) A luminous object is placed at a distance of 30 cm from the convex lens of focal length 20 cm. On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature 10 cm be placed in order to have an up-right image of the object coincident with it Show Answer

Q267) A point source of light is placed 4 m below the surface of water of refractive index 5/3. The minimum diameter of a disc which should be placed above the source on the surface of water to cut-off all light coming out of water is Show Answer

Q268) The focal length of the objective and eye lenses of a telescope are respectively 200 cm and 5 cm. The maximum magnifying power of the telescope will be Show Answer

Q269) A polariser is used to Show Answer

Q270) A person having normal vision is able to just resolve two poles separated by a distance of 1 m. The distance of the poles from the person is Show Answer

Q271) A convex lens of focal length 40 cm is combined with a concave lens of focal length 40 cm and placed in contact. The focal power of the combination is Show Answer

Q272) If Young's experiment with one source of light and two slits be performed so that interfering beam traverse in water instead of air Show Answer

Q273) Young's double slit experiment is performed with 500 nm light, slit separation 1 mm and screen distance 1 m. A and B are bright bands and C is a dark band. The distance AB is Show Answer

Q274) A ray of unpolarised light is incident on a glass plate at the polarising angle. Then Show Answer

Q275) A glass slab of thickness 4 cm contains the same number of waves as 5 cm of water when both are traversed by the same monochromatic light. If the refractive index of water is 4/3, what is that of glass? Show Answer

Q276) You are looking through an illuminated spectrometer slit. When the width of the slit is decreased, you will find Show Answer

Q277) A blue cross on a white background illuminated with white light is observed through a red filter. What is seen? Show Answer

Q278) In a terrestrial telescope, the focal lengths of objective, inverting lens and eye lens are 90 cm, 5 cm and 6 cm respectively. Then for relaxed vision, the minimum length of the tube will be Show Answer

Q279) To increase the resolving power of a microscope Show Answer

Q280) The energy of a visible photon is of the order of Show Answer

Q281) When a ray of light enters a glass slab from air Show Answer

Q282) We have a source of red light and a blue light of same power. Then the red light gives photons per second Show Answer

Q283) Focal length of a convex lens will be maximum for Show Answer

Q284) If the distance of the far point for a myopia patient is doubled, the focal length of the lens required to cure it will become Show Answer

Q285) Light is incident at an angle i and refracts to an angle r into a glass plate of uniform thickness t. The lateral displacement of incident ray at emergence is Show Answer

Q286) Two nicol prisms (polariser and analyser) have their axes at angle 60 degrees in between. If I is the intensity of light falling on first nicol, then that of emerging light from the second nicol is Show Answer

Q287) A blue object on a white background when seen through a blue filter will appear Show Answer

Q288) In Young's double slit experiment the width of one slit is double that of the other. The ratio of intensity of a bright band to that of a dark band in the interference pattern produced by them, is Show Answer

Q289) An observer looks at a tree of height 15 m with a telescope of magnifying power 10. To him the tree appears Show Answer

Q290) A concave mirror of focal length f produces an image, n times the size of the object. If the image is real, then the distance of the object from the mirror is Show Answer

Q291) When the length of a microscope increases its magnifying power Show Answer

Q292) If the luminous intensity of a unidirectional bulb is 100 candela, then total luminous flux emitted from the bulb is Show Answer

Q293) A convex - concave lens has faces of radii 3 cm and 4 cm respectively and is made of glass of refractive index 1.6. Its focal length is Show Answer

Q294) Two coherent sources of intensity ratio 9 : 4 produces interference. What is the ratio between the maxima and minima in the interference pattern produces by them? Show Answer

Q295) A diffraction grating has 5000 lines / cm . The maximum order visible with wavelength 6000 A is Show Answer

Q296) The image formed by a convex mirror of focal length 30 cm is a quarter of the size the object. The distance of the object from the mirror is Show Answer

Q297) Two lenses are placed in contact with each other and the focal length of combination is 80 cm. If the focal length if one is 20 cm, then the power of the other will be Show Answer

Q298) The focal length of an objective and eye lens are 120 cm and 6 cm respectively. If the angle subtended by an object situated at far point on the objective is 2', then for relaxed vision the angle subtended by an image on objective will be Show Answer

Q299) A set of letters which have been coloured are kept below a plane glass slab, which of the coloured letter will appear the most raised above others Show Answer

Q300) The full image of an object is formed on the screen by a convex lens. If now an opaque object covers half of the lens then Show Answer

Q301) There is an interference because of two waves of intensity I each, then the maximum intensity obtained is Show Answer

Q302) For the largest distance of the image from a convex mirror of focal length 10 cm, the object should be kept at Show Answer

Q303) The refractive indices of glass and water with respect to air are 3/2 and 4/3 respectively the refractive index of glass with respect to water will be Show Answer

Q304) A divergent lens will produce Show Answer

Q305) If the position of objective lens and eye piece lens are interchanged in a microscope, then the instrument will be have as Show Answer

Q306) A long sighted person has a minimum distance of distinct vision of 50 cm. He wants to reduce it to 25 cm. He should use a Show Answer

Q307) In a young's double slit experiment, the separation between the slits is d and the distance of the screen from the slits is D. The adjacent bright fringes are separated by a distance y. When D and d are simultaneously doubled, the fringes separation becomes Show Answer

Q308) The radii of curvature of a thin double convex lens is 15 cm and 10 cm respectively. If the refractive index of the material is 1.5, the focal length of the lens will be Show Answer

Q309) As astronomical telescope has an objective of focal length 100 cm and diameter 10 cm. Its eye piece is of focal length 5 cm and of diameter 2 cm. With the telescope in normal adjustment, the angular magnification is Show Answer

Q310) A convex lens of focal length 40 cm is in contact with a concave length of focal length 25 cm the power of the combination in diopters is Show Answer

Q311) In a Young's double slit experiment using red and blue lights of wavelengths 600 nm and 480 nm respectively, the value of n for which the red fringe coincides with (n + 1) th blue fringe is Show Answer

Q312) Which of the following cannot be polarised? Show Answer

Q313) Two waves have their amplitudes in the ratio of 1 : 9. The maximum and minimum intensities when they interface are in the ratio Show Answer

Q314) In a Young's double slit experiment, the source illuminating the slits its changed from blue to violet. The width of the fringes Show Answer

Q315) A satisfactory photographic print is obtained when the exposure time is 10 secs at a distance of 2 m from a 60 cd lamp. The time of exposure required for the same quality print at a distance of 4 m from a 120 cd lamp. Show Answer

Q316) Polarization of light takes place due to many processes. Which of the following will not cause polarization? Show Answer

Q317) In a compound microscope, the intermediate image is Show Answer

Q318) In a vessel of depth 15 cm, liquid is poured till the liquid level appears to be at half the depth, the liquid level is 5 cm from the top. Calculate the refractive index of the liquid Show Answer

Q319) When the complete Young's double slit apparatus is immersed in water, the fringes Show Answer

Q320) In Young's double slit experiment the separation between the slits is halved and distance between the slits and the screen is doubled. The fringe width is Show Answer

Q321) A lens having focal length and aperture of diameter d forms an image of intensity I . Aperture of diameter d/2 in central region of lens is covered by a black paper. Focal length of lens and intensity of image now will be respectively Show Answer

Q322) Which of the following is not due to total internal reflection? Show Answer

Q323) A biconvex lens has a radius of curvature of magnitude 20 cm. Which one of the following options describe best the image formed of an object of height 2 cm placed 30 cm from the lens? Show Answer