STD 12 - Ray optics and optical instruments PYQs: JEE Mains Physics – Page 3

Showing 101–150 of 248 questions

101. 101. A convex lens of refractive index \(1.5\) and focal length \(18 cm\) in air is immersed in water. The change in focal length of the lens will be \(...........cm\).\(\left(\right.\) Given refractive index of water \(\left.=\frac{4}{3}\right)\) 2023 Medium
102. 102. A fish rising vertically upward with a uniform velocity of \(8\,ms ^{-1}\), observes that a bird is diving vertically downward towards the fish with the velocity of \(12\,ms ^{-1}\). If the refractive index of water is \(\frac{4}{3}\), then the actual velocity of the diving bird to pick the fish, will be \(.......\,ms ^{-1}\). 2023 Medium
103. 103. A monochromatic light wave with wavelength \(\lambda_1\) and frequency \(v_1\) in air enters another medium. If the angle of incidence and angle of refraction at the interface are \(45^{\circ}\) and \(30^{\circ}\) respectively, then the wavelength \(\lambda_2\) and frequency \(v_2\) of the refracted wave are : 2023 Medium
104. 104. A person has been using spectacles of power- \(1.0\) diopter for distant vision and a separate reading glass of power \(2.0\) diopters. What is the least distance of distinct vision for this person \(.......cm\) 2023 Hard
105. 105. A point object, \(O\) is placed in front of two thin symmetrical coaxial convex lenses \(L _1\) and \(L _2\) with focal length \(24\,cm\) and \(9\,cm\) respectively. The distance between two lenses is \(10\,cm\) and the object is placed \(6\,cm\) away from lens \(L _1\) as shown in the figure. The distance between the object and the image formed by the system of two lenses is .........\(cm\)
     2023 Hard
106. 106. A pole is vertically submerged in swimming pool, such that it gives a length of shadow \(2.15 \,m\) within water when sunlight is incident at an angle of \(30^{\circ}\) with the surface of water. If swimming pool is filled to a height of \(1.5\,m\), then the height of the pole above the water surface in centimetres is \(\left(\eta_W=4 / 3\right)........\) 2023 Hard
107. 107. A ray of light is incident from air on a glass plate having thickness \(\sqrt{3} \,cm\) and refractive index \(\sqrt{2}\). The angle of incidence of a ray is equal to the critical angle for glass-air interface. The lateral displacement of the ray when it passes through the plate is \(.......\times 10^{-2}\) (given \(\sin 15^{\circ}=0.26\) ) 2023 Medium
108. 108. A thin cylindrical rod of length \(10\,cm\) is placed horizontally on the principle axis of a concave mirror of focal length \(20\,cm\). The rod is placed in a such a way that mid point of the rod is at \(40\,cm\) from the pole of mirror. The length of the image formed by the mirror will be \(\frac{x}{3} cm\). The value of \(x\) is \(............\). 2023 Hard
109. 109. A thin prism \(P_1\) with an angle \(6^{\circ}\) and made of glass of refractive index \(1.54\) is combined with another prism \(P _2\) made from glass of refractive index \(1.72\) to produce dispersion without average deviation. The angle of prism \(P_2\) is \(........{}^{\circ}\) 2023 Medium
110. 110. A vessel of depth \(d\) is half filled with oil of refractive index \(n_1\) and the other half is filled with water of refractive index \(n_2\). The apparent depth of this vessel when viewed from above will be 2023 Medium
111. 111. An ice cube has a bubble inside. When viewed from one side the apparent distance of the bubble is \(12\,cm\). when viewed from the opposite side, the apparent distance of the bubble is observed as \(4\,cm\). If the side of the ice cube is \(24\,cm\), the refractive index of the ice cube is \(.....\). 2023 Medium
112. 112. An object is placed at a distance of \(12\,cm\) in front of a plane mirror. The virtual and erect image is formed by the mirror. Now the mirror is moved by \(4\,cm\) towards the stationary object. The distance by which the position of image would be shifted, will be: 2023 Medium
113. 113. An object is placed on the principal axis of convex lens of focal length \(10\,cm\) as shown. A plane mirror is placed on the other side of lens at a distance of \(20\,cm\). The image produced by the plane mirror is \(5\,cm\) inside the mirror. The distance of the object from the lens is \(............cm\).
     2023 Hard
114. 114. As shown in the figure, a combination of a thin plano concave lens and a thin plano convex lens is used to image an object placed at infinity. The radius of curvature of both the lenses is \(30\,cm\) and refraction index of the material for both the lenses is \(1.75\). Both the lenses are placed at distance of \(40\,cm\) from each other. Due to the combination, the image of the object is formed at distance \(x =..........cm\), from concave lens.
     2023 Hard
115. 115. As shown in the figure, a plane mirror is fixed at a height of \(50\,cm\) from the bottom of tank containing water \(\left(\mu=\frac{4}{3}\right)\). The height of water in the tank is \(8\,cm\). A small bulb is placed at the bottom of the water tank. The distance of image of the bulb formed by mirror from the bottom of the tank is \(......cm\)
     2023 Hard
116. 116. Given below are two statements: one is labelled as Assertion \(A\) and the other is labelled as Reason \(R\) Assertion \(A\): The phase difference of two light waves change if they travel through different media having same thickness, but different indices of refraction. Reason \(R:\) The wavelengths of waves are different in different media. In the light of the above statements, choose the most appropriate answer from the options given below 2023 Medium
117. 117. In a medium the speed of light wave decreases to \(0.2\) times to its speed in free space The ratio of relative permittivity to the refractive index of the medium is \(x: 1\). The value of \(x\) is \(...........\) (Given speed of light in free space \(=3 \times 10^8 m s ^{-1}\) and for the given medium \(\mu_{ r }=1\) ) 2023 Medium
118. 118. In a reflecting telescope, a secondary mirror is used to: 2023 Medium
119. 119. In an experiment for estimating the value of focal length of converging mirror, image of an object placed at \(40\,cm\) from the pole of the mirror is formed at distance \(120\,cm\) from the pole of the mirror. These distances are measured with a modified scale in which there are \(20\) small divisions in \(1\,cm\). The value of error in measurement of focal length of the mirror is \(1 / K\) \(cm\). The value of \(K\) is  \(..........\) 2023 Hard
120. 120. In an experiment of measuring the refractive index of a glass slab using travelling microscope in physics lab, a student measures real thickness of the glass slab as \(5.25\,mm\) and apparent thickness of the glass slab at \(5.00\,mm\). Travelling microscope has \(20\) divisions in one \(cm\) on main scale and \(50\) divisions on Vernier scale is equal to \(49\) divisions on main scale. The estimated uncertainty in the measurement of refractive index of the slab is \(\frac{x}{10} \times 10^{-3}\), where \(x\) is \(..............\) 2023 Hard
121. 121. The critical angle for a denser-rarer interface is \(45^{\circ}\). The speed of light in rarer medium is \(3 \times 10^8\) ms. The speed of light in the denser medium is: 2023 Medium
122. 122. The light rays from an object have been reflected towards an observer from a standard flat mirror, the image observed by the observer are :- \(A.\) Real \(B.\) Erect \(C.\) Smaller in size then object \(D.\) Laterally inverted Choose the most appropriate answer from the options given below : 2023 Medium
123. 123. The radius of curvature of each surface of a convex lens having refractive index \(1.8\) is \(20\,cm\). The lens is now immersed in a liquid of refractive index \(1.5\). The ratio of power of lens in air to its power in the liquid will be \(x : 1\). The value of \(x\) is \(.....\) 2023 Medium
124. 124. The refractive index of a transparent liquid filled in an equilateral hollow prism is \(\sqrt{2}\). The angle of minimum deviation for the liquid will be 2023 Medium
125. 125. Two convex lenses of focal length \(20\,cm\) each are placed coaxially with a separation of \(60\,cm\) between them. The image of the distant object formed by the combination is at \(...........\,cm\) from the first lens. 2023 Medium
126. 126. Two objects \(A\) and \(B\) are placed at \(15\,cm\) and \(25\,cm\) from the pole in front of a concave mirror having radius of curvature \(40 cm\). The distance between images formed by the mirror is \(..........\,cm\) 2023 Medium
127. 127. Two transparent media having refractive indices \(1.0\) and \(1.5\) are separated by a spherical refracting surface of radius of curvature \(30\,cm\). The centre of curvature of surface is towards denser medium and a point object is placed on the principle axis in rarer medium at a distance of \(15\,cm\) from the pole of the surface. The distance of image from the pole of the surface is .......\(cm\) 2023 Medium
128. 128. Two vertical parallel mirrors \(A\) and \(B\) are separated by \(10\,cm\). A point object \(O\) is placed at a distance of \(2\,cm\) from mirror \(A\). The distance of the second nearest image behind mirror A from the mirror \(A\) is \(.........\,cm\)
     2023 Medium
129. 129. When a beam of white light is allowed to pass through convex lens parallel to principal axis, the different colours of light converge at different point on the principle axis after refraction. This is called: 2023 Medium
130. 130. When one light ray is reflected from a plane mirror with \(30^{\circ}\) angle of reflection, the angle of deviation of the ray after reflection is \(.....^{\circ}\) 2023 Easy
131. 131. Which of the following are true? \(A.\) Speed of light in vacuum is dependent on the direction of propagation. \(B.\) Speed of light in a medium in independent of the wavelength of light. \(C.\) The speed of light is independent of the motion of the source. \(D.\) The speed of light in a medium is independent of intensity. Choose the correct answer from the option given below : 2023 Medium
132. 132. A convex lens of focal length \(20\,cm\) is placed in front of convex mirror with principal axis coinciding each other. The distance between the lens and mirror is \(10\,cm\). A point object is placed on principal axis at a distance of \(60\,cm\) from the convex lens. The image formed by combination coincides the object itself. The focal length of the convex mirror is \(...cm\). 2022 Medium
133. 133. A light ray is incident, at an incident angle \(\theta_{1}\), on the system of two plane mirrors \(M_{1}\) and \(M_{2}\) having an inclination angle \(75^{\circ}\) between them (as shown in figure). After reflecting from mirror \(M_{1}\) it gets reflected back by the mirror \(M _{2}\) with an angle of reflection \(30^{\circ}\). The total deviation of the ray will be \(\dots\) degree.
     2022 Medium
134. 134. A light wave travelling linearly in a medium of dielectric constant \(4,\) incident on the horizontal interface separating medium with air. The angle of incidence for which the total intensity of incident wave will be reflected back into the same medium will be (Given : relative permeability of medium \(\mu_{ s }=1)\)  2022 Hard
135. 135. A parallel beam of light is allowed to fall on a transparent spherical globe of diameter \(30 \,cm\) and refractive index \(1.5\). The distance from the centre of the globe at which the beam of light can converge is________ \(mm\) 2022 Hard
136. 136. A ray of ligh is incident at an angle of incidence \(60^{\circ}\) on the glass slab of refractive index \(\sqrt{3}\). After refraction, the light ray emerges out from other parallel faces and lateral shift between incident ray and emergent ray is \(4 \sqrt{3} \,cm\). The thickness of the glass slab is. . .  .. . \(cm\). 2022 Medium
137. 137. A small bulb is placed at the bottom of a tank containing water to a depth of \(\sqrt{7} \; m\). The refractive index of water is \(\frac{4}{3}\). The area of the surface of water through which light from the bulb can emerge out is \(x \,\pi m ^{2}\). The value of \(x\) is ............... 2022 Medium
138. 138. A thin prism of angle \(6^{\circ}\) and refractive index for yellow light \(\left(n_{Y}\right) 1.5\) is combined with another prism of angle \(5^{\circ}\) and \(n _{ Y }=1.55\). The combination produces no dispersion. The net average deviation ( \(\delta\) ) produced by the combination is \(\left(\frac{1}{x}\right)^{\circ}\). The value of \(x\) is.......
     2022 Medium
139. 139. An object ' \(o\) ' is placed at a distance of \(100\,cm\) in front of a concave mirror of radius of curvature \(200\,cm\) as shown in the figure. The object starts moving towards the mirror at a speed \(2\,cm / s\). The position of the image from the mirror after \(10\,s\) will be at ...... \(cm\).
     2022 Hard
140. 140. As shown in the figure, after passing through the medium \(1\). The speed of light \(v _{2}\) in medium \(2\) will be\(.....\times 10^{8}\,ms ^{-1}\)  \(\left(\text { Given } c =3 \times 10^{8} ms ^{-1}\right)\)
     2022 Medium
141. 141. Consider a light ray travelling in air is incident into a medium of refractive index \(\sqrt{2 n}\). The incident angle is twice that of refracting angle. Then, the angle of incidence will be 2022 Hard
142. 142. For an object placed at a distance \(2.4\,m\) from a lens, a sharp focused image is observed on a screen placed at a distance \(12\,cm\) from the lens. A glass plate of refractive index \(1.5\) and thickness \(1\,cm\) is introduced between lens and screen such that the glass plate plane faces parallel to the screen. By what distance should the object be shifted so that a sharp focused image is observed again on the screen \(\dots\,m\) 2022 Hard
143. 143. If a wave gets refracted into a denser medium, then which of the following is true? 2022 Medium
144. 144. In an experiment with a convex lens. The plot of the image distance (\(v'\)) against the object distance \(\left(\mu^{\prime}\right)\) measured from the focus gives a curve \(v^{\prime} \mu^{\prime}=225\). If all the distances are measured in \(cm\). The magnitude of the focal length of the lens is \(cm\). 2022 Medium
145. 145. In free space, an electromagnetic wave of \(3 \; GHz\) of \(3 \; GHz\) frequency strikes over the edge of an object of size \(\frac{\lambda}{100}\), where \(\lambda\) is the wavelength of the wave in free space. The phenomenon, which happens there will be ..... 2022 Hard
146. 146. In normal adjustment, for a refracting telescope, the distance between objective and eye piece is \(30\,cm\). The focal length of the objective, when the angular magnification of the telescope is \(2\) , will be \(.....cm\)  2022 Medium
147. 147. In the given figure, the face \(AC\) of the equilateral prism is immersed in a liquid of refractive index ' \(n\) '. For incident angle \(60^{\circ}\) at the side \(AC\), the refracted light beam just grazes along face \(AC\). The refractive index of the liquid \(n =\frac{\sqrt{ x }}{4}\). The value of \(x...\) is (Given refractive index of glass \(=1.5\) )
     2022 Medium
148. 148. Light enters from air into a given medium at an angle of \(45^{\circ}\) with interface of the air-medium surface. After refraction, the light ray is deviated through an angle of \(15^{\circ}\) from its original direction. The refractive index of the medium is. 2022 Medium
149. 149. Light travels in two media \(M _{1}\) and \(M _{2}\) with speeds \(1.5 \times 10^{8} ms ^{-1}\) and \(2.0 \times 10^{8} ms ^{-1}\) respectively. The critical angle between them is. 2022 Medium
150. 150. The difference of speed of light in the two media \(A\) and \(B\,\left(v_{A}-v_{B}\right)\) is \(2.6 \times 10^{7}\,m / s\). If the refractive index of medium \(B\) is \(1.47\), then the ratio of refractive index of medium \(B\) to medium \(A\) is: (Given : speed of light in vacuum \(\left.c =3 \times 10^{8}\, ms ^{-1}\right)\) 2022 Hard

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