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question_answer1) A convex lens focuses a distant object 40 cm from it on a screen placed 10 cm away from it. A glass plate \[\left( \mu =1.5 \right)\]and of thickness 3 cm is inserted between the lens and the screen. Where should the object be placed so that its image is again focused on the screen? (in cm)
question_answer2) A convex lens of focal length 15 cm is placed coaxially in front of a convex mirror. The lens is 5 cm from the pole of the mirror. When an object is placed on the axis at a distance of 20 cm from the lens, it is found that the image coincides with the object. Calculate the radius of curvature of the mirror-(consider all optical event) (in cm)
question_answer3) A convex lens d A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with a distance d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then d is equal to, (in cm)
question_answer4) The focal length of a planoconvex lens is 20 cm. The plane face of it is silvered. An illumination object is placed at a distance of 60 cm from the lens on its axis on the convex side. Then the distance of the image is (in cm)
question_answer5) An object is placed at a distance of 15 cm from a convex lens of focal length 10 cm. On the other side of the lens, a convex mirror is placed at its focus such that the image formed by the combination coincided with object itself. The focal length of the convex mirror is (in cm)
question_answer6) A thin equiconvex lens has focal length 10 cm and refractive index 1.5. One of its faces is now silvered and for an object placed at a distance \[u\] in front of it, the image coincides with the object. The value of u is (in cm)
question_answer7) A convex lens of focal length 20 cm and a concave lens of focal length f are mounted coaxially 5 cm apart. Parallel beam of light incident on the convex lens emerges from the concave lens as a parallel beam. Then f (in cm) is ?
question_answer8) In the arrangement shown given that a biconvex lens of radius of curvature equal to 10 cm and concave mirror has focal length equal to 20 cm. Then find the distance 'x' (in cm) such that the final image formed by the system coincides with the object-
question_answer9) A plano convex lens of refractive index 1.5 and radius of curvature 30 cm is silvered at the curved surface. Now this lens has been used to form the image of an object. At what distance (in cm) from this lens an object be placed in order to have a real image of the size of the object-
question_answer10) A point object O is placed on the principal axis of a convex lens of focal length \[f\text{ }=\text{ }20\]cm at a distance of 40 cm to the left of it. The diameter of the lens is 10 cm. An eye is placed 60 cm to right of the lens and a distance \[h\]below the principal axis. The maximum value of \[h\](in meter) to see the image is-
question_answer11) A light ray incident on a plane interface of an irregular glass slab (refractive index\[=\surd 2\]) at an angle of incidence\[45{}^\circ \], Angle of inclination of this interface is\[60{}^\circ \]. Its other interface is curve of (radius of curvature\[=0.4\text{ }m\]). The ray after entering into another medium \[\left( {{\mu }_{3}}=1.514 \right)\]meets principal axis PQ at E as shown in the figure. Find distance OE (in meter)
question_answer12) A ray is incident on a glass sphere as shown. The opposite surface of the sphere is partially silvered. If the net deviation of the ray transmitted at the partially silvered surface is \[\frac{1}{3}rd\]of the net deviation suffered by the ray reflected at the partially silvered surface (after emerging out of the sphere). The refractive index of the sphere \[\frac{a}{\sqrt{3}}\]then the value of a is.
question_answer13) A convex lens is held 45cm above the bottom of an empty tank. The image of a point on the bottom of a tank is formed 36cm above the lens. Now liquid is poured into the tank to a depth of 40cm. It is found that the distance of the image of the same point on the bottom of the tank is 40cm above the lens. The refractive index of the liquid is \[\frac{8}{a}\]then value of a is.
question_answer14) A convex lens B of focal length 20cm is placed at a distacne of 30cm to the right of an identical lens A. A point object is placed at a distance of 30cm to the left of A. On the common axis of the two lenses should a convex mirror of radius of curvature 7cm be placed from lens B so that the final image coincides with the objects (in cm).
question_answer15) Plane surface of a thin planoconvex lens reflects 50 % of light, while the curved surface is completely transparent, if final image of ?O? after refraction through thin less coincides with the image formed due to partial reflection from plane surface. If distance between O and lens is x (in m) then find the value of x/4.
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