TS EAPCET (Engineering) Ray Optics and Optical Instruments — practice questions
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Practice TS EAPCET (Engineering) Ray Optics and Optical Instruments in the app →A convex lens forms a real image at $60$ cm on one side of an object placed $20$ cm in front of it. Find the fTwo thin lenses of focal lengths $+10$ cm and $+20$ cm are placed in contact. The power of the combination, inA light ray travels from glass ($\mu = 1.5$) to air. The critical angle for total internal reflection at the gThe relation between focal length f and radius of curvature R for a spherical mirror is:The mirror equation (relating object distance u, image distance v, focal length f) is:The linear magnification produced by a spherical mirror is given by:A convex (diverging) mirror always forms an image that is:If n₂₁ is the refractive index of medium 2 w.r.t. medium 1, then n₁₂ equals:When light passes through a rectangular glass slab, the emergent ray is:For light going from a medium of refractive index n to air, the critical angle i_c is given by:The critical angle for diamond (n ≈ 2.42) and water (n ≈ 1.33) is approximately:The lens-maker's formula for a thin lens (refractive index n) with radii of curvature R₁ and R₂ is:The magnification produced by a thin lens is:The power P of a lens with focal length f (in metres) is:Which colour of light deviates LEAST when white light passes through a glass prism?The speed of light in vacuum is approximately:For a concave lens (diverging lens), the image of a real object is always:Snell's law of refraction states:For a plane mirror, image is:Focal length of a concave mirror with radius of curvature R:Mirror formula relating object distance u, image distance v, focal length f:Magnification by a mirror:Refractive index of water is 1.33. Critical angle for water-air interface:For a thin lens, lens-maker's formula:For a convex lens, an object at 2f forms image at:Power of a lens (P) is defined as:Two thin lenses of powers P₁ and P₂ in contact give combined power:Refraction by a prism: deviation δ depends on:In a compound microscope, magnification by objective is m_o, eyepiece is m_e. Total magnification:Telescope's angular magnification (normal adjustment, image at infinity):Speed of light in a medium of refractive index n:Object at focus of a convex lens. Image is:An object 4 cm tall is placed 30 cm in front of a concave mirror of focal length 20 cm. Image position and sizFor an apparent depth of swimming pool seen from above (real depth d, water n = 4/3):Critical angle for diamond (n = 2.42):Combination of two lenses, f₁ = 20 cm convex and f₂ = -25 cm concave, in contact. Equivalent power:Dispersion of light by prism: angular dispersion (δ_violet - δ_red) for thin prism:A coin at the bottom of a 0.5 m water tank (n = 4/3) appears at depth:In Young's double slit experiment, fringe width:Refractive index of medium 1 w.r.t. medium 2 is n₁₂. Then:Magnifying power of simple magnifier (image at near point):For object at 60 cm from convex lens of f = 20 cm, image is:For total internal reflection at glass-water interface (n_g = 1.5, n_w = 1.33), critical angle:A ray enters a glass slab at 45°. Glass n = 1.5. Angle of refraction inside glass:In Cartesian convention, a concave mirror has a focal length that isWhich spherical mirror has a positive focal length in Cartesian convention?A spherical mirror has a radius of curvature of 30 cm. Its focal length is aboutDistances measured along the direction of the incident light are taken asFrom which point on a spherical mirror are all distances measured?Heights measured downwards from the principal axis are taken asWhich equation connects u, v and f for a spherical mirror?The thin lens formula relating u, v and f isThe lens maker's formula makes 1/f proportional toA diverging lens has a focal length that isA concave lens has a focal length of 50 cm. Its power isTwo thin lenses of focal lengths 20 cm and 30 cm are in contact. Combined focal length?Splitting of light into its constituent colours is calledA magnifier of f = 5 cm is adjusted for viewing at 25 cm. Magnifying power?A magnifier of f = 10 cm is set for relaxed viewing at infinity. Its magnification isThe least distance of distinct vision is taken asTotal magnifying power of a compound microscope isA telescope has fo = 100 cm and fe = 1 cm. Its magnifying power isTube length of an astronomical telescope in normal adjustment isA 100x telescope views stars 1 arcminute apart. They seem separated by aboutWhich telescope adds inverting lenses so the object looks erect?Light gathering power of a telescope depends on its objective'sBetter resolving power in a telescope needs an objective with largerTelescopes with mirror objectives are calledWhich defect is absent when a mirror serves as the objective?A Cassegrain telescope uses which secondary mirror?Each of the Keck telescopes in Hawaii has a reflector about how wide?Giant lens objectives are rarely built because they areA telescope mirror is easier to support than a lens because it can be heldMain drawback of putting the eyepiece at a reflector's focus isThe angle of incidence that gives a 90° angle of refraction is theGlass of refractive index 2 lies in air. Its critical angle isA material has a critical angle of 45° in air. Its refractive index isAn optical fibre works on the principle ofIn an optical fibre, the core compared with the cladding hasPrisms that bend light by 90° via total reflection need a critical angle belowAt minimum deviation, the ray inside a prism isAt minimum deviation in a prism, the angles satisfyA 60° prism has minimum deviation of 30°. Its refractive index is aboutA thin prism of angle 4° and n = 1.5 deviates light by aboutApart from minimum deviation, each deviation in a prism occurs forA simple microscope is a converging lens ofFor relaxed viewing at infinity, a magnifier's object is placedThick lenses give coloured images because ofThe laws of reflection hold at each point ofFor a spherical mirror the normal at the point of incidence lies along theThe geometric centre of a spherical lens is called itsThe line joining a mirror's pole and centre of curvature is itsFor a given pair of media, the ratio sin i to sin r isWhich lens aberration arises from variation of refractive index with wavelength?A comet-shaped smear of an off-axis point source is calledWhich aberration arises because spherical surfaces are not an ideal lens shape?Automatic wiper rain sensors rely on which principle?Which retinal cells respond to low intensity light?Which structure controls the lens shape for near focus?The jelly-like substance behind the eye lens is theTotal internal reflection can occur only when a ray travels fromA concave mirror has f = 15 cm and the object is 30 cm away. Find v.An equiconvex glass lens (n = 1.5) has both radii 20 cm and lies in air. Its focal length isA thin prism has angle 4° and refractive index 1.5. What is its deviation?For a ray refracted through a prism of angle A, the internal refraction angles r1 and r2 satisfyA ray passes symmetrically (i = e = 40°) through a 60° prism. Its deviation isAt minimum deviation through a prism, the angle of incidence i and the angle of emergence e areA simple magnifier has focal length 5 cm and the eye views at infinity. What is the magnifying power?What focal length gives a magnification of 6 when the eye views at the 25 cm near point?A simple microscope consists of which kind of lens?With an object at the focal point of a simple magnifier, the emerging rays appear to come fromAn astronomical telescope in normal use has fo = 80 cm and fe = 2 cm. What is its tube length?The resolving power of a telescope objective mainly depends onWhy do big telescopes use a concave mirror as objective?The largest telescope in India, at Kavalur in Tamil Nadu, has a mirror of diameterThe pair of Keck telescopes in Hawaii each use a reflector of diameterThe brilliance of a cut diamond owes much to multiple internal reflections, since its critical angle is aboutA concave mirror (f = 10 cm) has an object 5 cm in front. What is the magnification?A telescope's objective has focal length 150 cm and its magnifying power is 30. The eyepiece focal length isA compound microscope has fe = 5 cm (near-point viewing, D = 25 cm) and objective power 10. Total magnificatio