Ray Optics and Optical Instruments-Quiz-10

RAY OPTICS AND OPTICAL INSTRUMENTS-10 Quiz

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JEE Advanced Physics Syllabus can be referred by the IIT aspirants to get a detailed list of all topics that are important in cracking the entrance examination. JEE Advanced syllabus for Physics has been designed in such a way that it offers very practical and application-based learning to further make it easier for students to understand every concept or topic by correlating it with day-to-day experiences. In comparison to the other two subjects, the syllabus of JEE Advanced for physics is developed in such a way so as to test the deep understanding and application of concepts..

Q1. In the above question, the magnification is

•  4/9
•  -4/9
•  9/4
•  8/13

Solution

m=-v/u=-(4/9)/(-1)=4/9

Q2.A glass prism has refractive index √2and refracting angle 30°. One of the refracting surface of the prism is silvered. A beam of monochromatic light will retrace it path if its angle of incidence on the unsilvered refracting surface of the prism is

•  0
•  π/6
•  π/4
•  π/3

Solution

Q3.  A point object is placed at a distance of 25 cm from a convex lens of focal length 20 cm. If a glass slab of thickness t and refractive index 1.5 is inserted between the lens and the object, the image if formed at infinity. The thickness t is

•   10 cm
•  5 cm
•  20 cm
•  15 cm

Solution

Image will be formed at infinity if object is placed at focus of the lens, i.e., at 20 cm from the lens. Hence, Shift =25-20=(1-1/μ)μ Or 5(1-1/1.5)tor t=(5×1.5)/0.5=15 cm

Q4. A lens forms a virtual, diminished image of an object placed at 2 m from it. The size of image is half of the object. Which one of the following statements is correct regarding the nature and focal length of the lens?

•  Concave, |f|=1 m
•  Convex, |f|=1
•  Concave, |f|=2 m
•  Convex, |f|=2 m

Solution


m=f/(f+u),1/2=f/(f-2); or 2f=f-2 or f=-2 m |f|=2 metre. Since the image is virtual as well as diminished, therefore the lens is concave

Q5.A convex lens forms an image of an object placed 20 cm away from it at a distance of 20 cm on the other side of the lens. If the object is moves 5 cm toward the lens, the image will be

•  5 cm toward the lens
•  5 cm away the lens
•  10 cm toward the lens
•  10 cm away the lens

Solution

Clearly, 2f=20 cm Or f=10 cm Now, u=-15 cm, v=? f=10 cm 1/v-1/(-15)=1/10 Or 1/v+1/15=1/10 or1/v=1/10-1/15 Or 1/v=(3-2)/30=1/30 Or v=30 cm The change in image distance is (30-20) cm, i.e., 10 cm

Q6. A cubic container is filled with a liquid whose refractive index increases linearly from top to bottom. Which of the following represents the path of a ray of light inside the liquid ?

 

 

 

Solution

Q7. A ray of light is incident on an equilateral glass prism placed on a horizontal table. For minimum deviation which of the following is true?

•  PQ is horizontal
•  QR is horizontal
•  RS is horizontald
•  Either PQ or RS is horizontal

Solution
During minimum deviation the ray inside the prism is parallel to the base of the prism in case of an equilateral prism.

Q8. A plane mirror is placed at origin parallel to y-axis, facing the positive x-axis. An object starts from (2 m, 0, 0) with a velocity of (2i ̂+2j ̂ ) ms^(-1). The relative velocity of the image with respect to the object is along

•  Positive x-axis
•  TNegative x-axis
•  Positive y-axis
•  Negative y-axis

Solution

Q9.A transparent sphere of radius 20 cm and refractive index 1.6 is fixed in a hole of the partition separating the two media: A (refractive index n_1=1.2) and B(refractive index n_3=1.7). A luminous point object is placed 120 cm from the surface of the sphere in medium A. It is viewed from D in medium B in a direction normal to the sphere. Find the position of the image formed by the rays, from point N

•  304 cm, left side of N
•  175 cm, right side of N
•  204 cm, right side of N
•  220 cm, left side of N

Solution

Q10. A point object is placed in front of a thick plane mirror as shown in figure below. Find the location of final image w.r.t. object

•  15/2 cm
•  15 cm
•  40/3 cm
• 80/3 cm

Solution