Optics — practice questions

164 curated practice questions from Optics (Physics JEE Main, NTA Exams) — 146 easy, 12 hard, 6 medium. Every question includes the final answer free; step-by-step worked solutions with a free account.

• Which one of the following phenomena is not explained by Huygen’s construction of wavefront?
• If a flint lens glass of dispersive power 0.066 renders achromatic to a convex lens of crown glass of focal length 60…
• For a real object, a convex mirror always forms an image which is
• A point source of light B is placed at a distance L in front of the centre of a mirror of width d hung vertically on a…
• Two waves having the intensities in the ratio of 9 : 1 produce interference. The ratio of maximum to minimum intensity…
• Refractive index of water relative to air is r_ n = 4 3 . When a photon enters from air to water, the fractional change…
• Two monochromatic and coherent point sources of light are placed at a certain distance from each other in the…
• A small source of light is 4 m below the surface of a liquid of refractive index 5 / 3 . In order to cut off all the…
• A short linear object of length b lies along the axis of a concave mirror of focal length f at a distance u from the…
• A ray of light is incident on the surface of a glass plate of refractive index 1.55 at the polarising angle. The angle…
• The Brewsters angle i b for an interface should be
• In the two separate set-ups of the Young’s double slit experiment, fringes of equal width are observed when lights of…
• The Young's double slit experiment is performed with blue and green light of wavelengths 4360 A and 5460 A…
• In Young's double slit experiment, the ratio of the maximum to minimum intensities in the fringe system is 9 : 1. The…
• In Young’s experiment the wavelength of red light is 7.8 × 10–5 cm and that of blue light is 5.2 × 10–5 cm. The value…
• For a small angled prism, angle of prism A, the angle of minimum deviation (δ) varies with the refractive index of the…
• A compound microscope is used to enlarge an object kept at a distance 0.03m from it’s objective which consists of…
• A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of…
• Given below are two statements. One is labelled as Assertion and the other is labelled as Reason. STATEMENT - 1…
• According to Newton's corpuscular theory, the speed of light is
• In a YDSE with two identical slits, when the upper slit is covered with a thin, perfectly transparent sheet of mica…
• In a Young's double slit experiment an electron beam is used to obtain interference pattern. If the speed of electrons…
• A diffraction pattern is obtained using a beam of red light. What happens if the red light is replaced by blue light?
• An achromatic prism is made by crown glass prism ( A _ c =19^ ) and flint glass prism (A_ F =6^ ) . If ^ c _ v =1.5 and…
• In a double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then…
• If velocity of light in a certain medium is 1.5 × 10 8 m/s, µ for the medium would be
• In a double slit interference experiment the distance between the slits is 0.05 cm and screen is 2 m away from the…
• A thin prism of angle 5^ is placed at a distance of 10 ~cm from object. What is the distance of the image from object?…
• In Young’s double slit experiment, the separation between the slits is halved and the distance between the slits and…
• A convex mirror of focal length f produces an image ( 1 n )^ th of the size of the object. The distance of the object…
• Electromagnetic waves are transverse in nature is evident by
• A concave spherical surface of radius of curvature 10 ~cm separates two medium x & y of refractive index 4 / 3 3 / 2…
• In an interference pattern produced by two identical slits, the intensity at the side of the central maximum is I. The…
• Light of wavelength λ is incident on a slit of width d. The resulting diffraction pattern is observed on a screen at a…
• In a Fraunhofer’s diffraction by a slit, if slit width is a, wavelength is , focal length of lens is f , linear width…
• A lens forms a sharp image on a screen. On inserting a parallel sided glass slab between the lens and the screen, it is…
• In a concave mirror an object is placed at a distance x 1 from the focus and the image is formed at a distance x 2 from…
• The refracting angle of prism is A and refractive index of material of prism is - . The angle of minimum deviation is
• The magnifying power of a compound microscope in terms of the magnifying power of objective M o and that of the…
• A spherical surface of radius of curvature 10 ~cm separates two media and of refractive indices 3 / 2 and 4 / 3…
• Two sources give interference pattern which is observed on a screen, D distance apart from the sources. The fringe…
• In Young's double slit experiment, wavelength of light used is 6000 a A . The screen is placed 40 cm from the slits and…
• The distance of an object from the focus of a convex mirror of radius of curvature ‘a’ is ‘b’. Then the distance of the…
• Two waves originating from sources S1 and S2 having zero phase difference and common wavelength λ will show completely…
• A ray of light is incident at the glass–water interface at an angle i, it emerges finally parallel to the surface of…
• Minimum thickness of a mica sheet having = 3 2 which should be placed in front of one of the slits in YDSE is required…
• A prism having an apex angle of O and refractive index of 1.50 is located in front of a vetical plane mirror as shown…
• In Young’s double slit experiment, one of the slits is so painted that intensity of light emitted from it is half of…
• A convergent lens of focal length 20 cm and made of a material with refractive index 1.1 is immersed in water of…
• A double convex lens of focal length 6 cm is made of glass of refractive index 1.5. The radius of curvature of one…
• Maxwell’s electromagnetic theory of light suggests that the light consists of oscillation of
• When a ray of light enters from one medium to another, then its velocity in second medium becomes double. The maximum…
• A virtual image three times the size of the object is obtained with a concave mirror of radius of curvature 36cm. The…
• Two waves of same wavelength and amplitude interfere to give a minimum when phase difference is
• A thin symmetrical double convex lens of power P is cut into three part, as shown in the figure. Power of A is :
• A thin convergent glass lens (µ g = 1.5) has a power of + 5.0 D. When this lens is immersed in a liquid of refractive…
• If in a plano-convex lens, radius of curvature of convex surface is 10 cm and the focal length of the lens is 30 cm…
• When unpolarised light is incident on a plane glass plate at Brewster’s (polarising) angle, then which of the following…
• In Young’s double slit experiment, if monochromatic light is replaced by white light:
• The magnification of the image when an object is placed at a distance x from the principal focus of a mirror of focal…
• Given below are two statments: One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A)…
• Two symmetric double convex lenses A and B have same focal length, but the radii of curvature differ so that R_ A =0.9…
• In Young’s experiment, one slit is covered with a blue filter and the other (slit) with a yellow filter. Then the…
• If two lenses of +5 diopters are mounted at some distance apart, the equivalent power will always be negative if the…
• In Young’s double slit experiment, a mica sheet of thickness t and refractive index is introduced in the path of ray…
• In the Young’s double slit experiment, the two equally bright slits are coherent, but of phase difference 3 . If the…
• If _ 0 amd µ 0 represent the permittivity and permeability of vacuum and and µ represent the permittivity and…
• Two slits separated by a distance of 1 mm are illuminated with red light of wavelength 6.5 × 10–7 m. The interference…
• The image of a bright object is brought on the screen with a concave mirror. If upper half of mirror is covered, what…
• A ray of light is incident on the surface of a glass plate at an angle of incidence equal to Brewster’s angle . If…
• The magnifying power of simple microscope can be increased if we use an eyepiece of
• In a double slit experiment, the first minimum on either side of the central maximum occurs where the path difference…
• When viewed in white light, soap bubbles show colours because of
• A fish is a little away below the surface of a lake. If the critical angle is 49°, then the fish could see things above…
• A graph is plotted between angle of deviation (δ) and angle of incidence (i) for a prism. The nearly correct graph is
• What is the magnification when the object is placed at a distance of 2f from the pole of a convex mirror?
• In young's double slit experiment angular width of fringes is 0.20^ for sodium light of wavelength 5890 ~A . If the…
• In a simple microscope, the distance of object from the lens should be
• A fish rising vertically with speed 3 m/s to the surface of water sees a bird diving vertically towards it with speed 9…
• Two transparent media A and B are separated by a plane boundary. The speed of light in medium A is 2.0 10^ 8 ~m ~s ^ -1…
• In Young's double-slit experiment the angular fringe width for the given light is Δθ. Now if wavelength of light is…
• The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30cm is 2 cm. If a…
• An air bubble in glass slab (µ = 1.5) appears to be at 6 cm from one side and 4 cm from other side. The thickness of…
• Diameter of human eye lens is 2 mm. What will be the minimum distance between two points to resolve them, which are…
• Parallel rays of light are focussed by a thin convex lens. A thin concave lens of same focal length is then joined to…
• The intensity ratio of the two interfering beams of light is β. What is the value of I_ -I_ I_ mox +I_ ?
• A convex mirror has a focal length f. A real object is placed at a distance f in front of it from the pole, produces an…
• In Young’s double slit experiment using sodium light ( = 5898Å), 92 fringes are seen. If given colour ( = 5461Å) is…
• The main difference in the phenomenon of interference and diffraction is that
• The focal length of a lens of refractive index 1.5 in air, is 15 cm. When it is immersed in a liquid of refractive…
• The angle of incidence at which reflected light is totally polarized for reflection from air to glass (refractive…
• A lens of power + 2 diopters is placed in contact with a lens of power – 1 diopoter. The combination will behave like
• In Young's double-slit experiment, the distance between two slits is d = 1 mm. Two light waves of wavelength _ 1 =500…
• A double convex lens made of material of refractive index 1.5 and having a focal length of 10 cm is immersed in a…
• A polaroid is placed at 45° to an incoming light of intensity I_ 0 . Now the intensity of light passing through…
• Wavelength of light used in an optical instrument are _ 1 =4000 and _ 2 =5000 , then ratio of their respective…
• The maximum number of possible interference maxima for slit-separation equal to twice the wavelength in Young's…
• A vessel is half filled with a liquid of refractive index µ. The other half of the vessel is filled with an immiscible…
• A glass concave lens is placed in a liquid in which it behave like a convergent lens. If the refractive indices of…
• The radius of curvature for a convex lens is 40 cm, for each surface. Its refractive index is 1.5 . The focal length…
• A ray of light strikes a glass plate at an angle of 60°. If the reflected and refracted rays are perpendicular to each…
• The curvature radii of a concavo-convex glass lens are 20 ~cm and 60 ~cm . The convex surface of thelens is silvered…
• Find the half angular width of the central bright maximum in the Fraunhofer diffraction pattern of a slit of width 12…
• Two point source separated by d=5 m emit light of wavelength =2 ~m in phase. A circular wire of radius 20 ~m is placed…
• Two thin lenses of focal lengths 20 cm and 25 cm are placed in contact. The power of the combination is
• In Huygen’s wave theory, the locus of all points in the same state of vibration is called
• The image formed by a convex mirror of focal length 30 cm is one quarter of the size of object. The distance of object…
• If an interference pattern has maximum and minimum intensities in the ratio of 36 : 1 then what will be the ratio of…
• In a YDSE experiment if a slab whose refractive index can be varied is placed in front of one of the slits then the…
• Which of the following statement is/are correct for coherent sources? I. Two coherent sources emit light waves of same…
• If the focal length of the objective lens and the eye lens are 4 mm and 25 mm respectively in a compound microscope…
• In the young’s double slit experiment, The intensity of the central maxima is observed to be I_ 0 . If one of the slits…
• A convex mirror is used to form an image of a real object. Then tick the wrong statement
• A beam of unpolarized light of intensity I0 is passed through a polaroid A and then through another polaroid B which is…
• In Young’s double slit experiment, the interference pattern is found to have an intensity ratio between bright and dark…
• The radius of curvature of the curved face of a thin planoconvex lens is 10 cm and it is made of glass of refractive…
• Two mirrors at an angle ^ produce 5 images of a point. The number of images produced when θ is decreased to -30^ is
• The displacement of the interfering light waves are y1 = 4 sin ωt and y2 = 3 sin (ωt + π/2) What is the amplitude of…
• Two beams, A and B, of plane polarized light with mutually perpendicular planes of polarization are seen through a…
• If the distance between the first maxima and fifth minima of a double slit pattern is 7 mm and the slits are separated…
• We shift young’s double slit experiment from air to water. Assuming that water is still and clear, it can be predicted…
• In Young's double slit experiment the maximum intensity obtained is l 0 . The intensity at a point on screen where the…
• A thin plano-convex lens of focal length 15 cm has its plane side silvered. An object is placed on the principal axis…
• If the slit width in Young's double slit experiment is reduced to d 3 , the fringe width becomes n times. The value of…
• A concave and convex lens have same focal length of 20 cm and are put in contact. The combination is used to view an…
• In Young’s double slit experiment if the slit widths are in the ratio 1 : 9, the ratio of the intensity at minima to…
• The first diffraction minima due to a single slit diffraction is at θ = 30° for a light of wavelength 5000 Å. The width…
• If the refractive index of water is 4/3 and that of glass slab is 5/3, then the critical angle of incidence for which a…
• A small plane mirror is placed at the centre of a spherical screen of radius R. A beam of light is falling on the…
• If the critical angle for total internal reflection from a medium to vacuum is 30°, then the velocity of light in the…
• In the YDSE shown the two slits are covered with thin sheets having thickness t & 2t and refractive index 2 and . Find…
• If the light is polarised by reflection, then the angle between reflected and refracted light is
• A beam of light AO is incident on a glass slab (μ = 1.54) in a direction as shown in figure. The reflected ray OB is…
• The radius of curvature of concave mirror is 24 cm and the image is magnified by 1.5 times. The object distance is
• In YDSE, the source placed symmetrically with respect to the slit is now moved parallel to the plane of the slits. It…
• A ray of light enters from a denser medium into rarer medium. The speed of light in the rarer medium is twice that in…
• A square of side 3cm is placed at a distance of 25cm from a concave mirror of focal length 10cm. The centre of the…
• A beam of monochromatic blue light of wavelength 420 nm in air travels in water (µ = 4/3). Its wavelength in water will…
• A Young's double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen…
• In YDSE how many maxima can be obtained on the screen if wavelength of light used is 200 nm and d = 700 nm:
• The diagram below shows, two sources A and B, vibrating in phase, in the same uniform medium and producing circular…
• A concave mirror is used to form an image of the sun on a white screen. If the lower half on the mirror were covered…
• 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 apparent depth of water in cylindrical water tank of diameter 2R cm is reducing at the rate of x cm/minute when…
• The objective of a telescope has focal length 120 cm and diameter 5 cm. The focal length of eyepiece is 2 cm. The…
• A beam of monochromatic blue light of wavelength 4200 A in air travels in water of refractive index 4/3. Its wavelength…
• An object is placed at 10 cm from a lens and real image is formed with magnification of 0.5 . Then the lens is :
• The critical angle for a medium is 60°. Then refractive index of the medium will be
• Which of the following is not true about the image formed by covex mirror?
• From Brewster’s law for polarisation, it follows that the angle of polarisation depends upon
• When a plane electromagnetic wave enters a glass slab, then which of the following will not change?
• The wavelength of sodium light is 589 nm in air. What will be the wavelength of sodium light if it travels in glass of…
• A concave mirror of focal length f produces an image n times the size of the object. If the image is real then the…
• Two slits in Youngs experiment have widths in the ratio 1 : 25. The ratio of intensity at the maxima and minima in the…
• The condition for observing Fraunhofer diffraction from a single slit is that the light wavefront incident on the slit…
• Light travels with a speed of 2 × 10 8 m/s in crown glass of refractive index 1.5. What is the speed of light in dense…
• To demonstrate the phenomenon of interference we require two sources which emit radiation of
• Two similar plano-convex lenses are combined together in three different ways as shown in the adjoining figure. The…
• A convex lens of focal length f is put in contact with a concave lens of same focal length. The focal length of…
• The focal length of objective of an astronomical telescope is 1 m. If the magnifying power of telescope is 20, then…
• In Young’s double slit interference experiment, the distance between two sources is 0.1 mm. The distance of the screen…
• Two thin lenses of focal lengths f 1 and f 2 are placed in contact. The focal length of the complete lens is
• Two plane mirrors. A and B are aligned parallel to each other, as shown in the figure. A light ray is incident at an…
• A 2.0 cm object is placed 15 cm in front of a concave mirror of focal length 10 cm. What is the size and nature of the…

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