Geometrical Optics Questions and Answers

Two glass plates 10 0 cm long are in contact at one end and separated at the other end by a thread 0 0500 mm in diameter Fig P37 39 Light containing the two wavelengths 400 nm and 600 nm is incident perpendicu larly and viewed by reflection At what distance from the contact point is the next dark fringe

A beam of 580 nm light passes through two closely spaced glass plates as shown in Figure P37 37 For what minimum nonzero value of the plate separation d is the transmitted light bright I

A small bulb is placed at the bottom of a tank containing water to a depth of 80 cm What is the area of the surface of water through which light from the bulb can emerge out Refractive index of water is 1 33 Consider the bulb to be a point source

In Young s double slit experiment with slit separation 0 1 mm one observes a bright fringe at angle 1 40 rad by using the light of wavelength 2 When the light of wavelength 22 is used a bright fringe is seen at the same angle in the same setup Given that 1 and 2 are in the visible range 380 nm to 740 nm their values are A 400 nm 500 nm B 625 nm 500 nm C 380 nm 525 nm D 380 nm 500 nm

31 32 33 34 As shown in figure a convergent lens is placed inside a cell filled with liquid The lens has focal length 20 cm when in air and its material has refractive index 1 50 If the liquid has refractive index 1 60 the focal length of the system is 25 26 Question Type Single Correct Type 1 2 80 cm 28 29 30 80 cm

21 A telescope has an objective lens of focal length 150 cm and an eyepiece of focal length 5 cm If a 50 m tall tower at a distance of 1 km is observed through this telescope in normal setting the angle formed by the image of the tower is 0 then 0 is close to al bj a 30 b 15 A metal sampl c 84 d 1 2

I have seen the solution of this question but I did not und erstand how and why have we used the concept of TIR her e How do we know that the angle is more than the critica angle and the angle of refraction is 90 6 A fish looking up through the water sees that the outside world is contained in a circular horizon if the refractive index of water is of the circle in centimeter is and the fish is 12 cm below the surface of water the radius

Bottom face of the glass cube is silvered as shown A ray of light is incident on to face of the cube as shown Find the deviation of the ray when it comes out of the glass cube 45 u 2 O O 0 90 O O 270 180

If the value of resistance is 10 845 ohm and the value of current is 3 23 amp the value of potential w significant numbers would be 1 35 0 volt BE000 2 3 50 volt nr 000

hoose true or false for each statement regarding convex mirrors If an object is placed 3 9 cm from a convex mirror with f 4 cm then its image will be reduced and virtual A convex mirror produces an enlarged virtual image when the object is placed far beyond its focal point Regi If an object is placed 8 1 cm from a convex mirror with f 4 cm then its image will be enlarged and virtual

An air bubble in glass u 1 5 5 is situated at a distance 3 cm from a convex surface of diameter 10 cm as shown The distance from surface at which the image of bubble appears is 1 5 3cm 1 4 I 1 2 5 cm 2 5 cm 3 4 cm 4 1 5 cm Aray of light is incident at angle of 60 on a cm fi th V W 14 Telegram neetqstion paper 3 3 4 A

Focal length of a convex lens of refractive index 1 5 is 2 cm Focal length of lens when immersed in a liquid of refractive index 1 25 will be 1 5 cm 3 10 cm 2 7 5 cm 4 2 5 cm

E TARGET PRE MEDIC Fig shows a plane mirror onto which a light ray is incident If the incidenting light ray is turned by 10 and the mirror by 20 as shown then the angle turned by the reflected ray is CAREER DISTITUTE ROTA THAMETHANE 10 30 1 30 clockwise 2 200 reflected ray 777 20 2 30 anticlock wise con antic

Two plane mirrors A and B are aligned parallel to each other as shown in the figure A light ray is incident at an angle of 30 at a point just inside one end of A The plane of incidence coincides with the plane of the figure The maximum number of time the ray undergoes reflections including the first one before it emerges out is 0 2m 1 28 2 3m 2 30 A B 2 3 elegram neetquestion paper

Two plane mirrors are inclined to each other such that a ray of light incident on the first mirror and parallel to the second is reflected from the seconc mirror parallel to the first mirror Determine the angle between the two mirrors 1 60 3 90 2 30 4 180

A glass prism of refractive index 1 5 is immersed in a liquid of refractive index as shown in the figure A light beam inciden 3 normally on the face PQ is totally reflected to reach the face QR if 1 5 sin 8 sin 8 O sine 0 9 0 0 8 9 34 2 4 3

un object with a height of 0 06 m points below the principal axis it is Inverted and is 0 140 m in front of a diverging lens The focal length of the lens is 0 26 m Include the sign of the value in your inswers a What is the image distance b What is the magnification m c What is the image height m

A biconvex thin lens of focal length 30 cm and aperture diameter 10 cm is broken into four identical pieces Two of the pieces are placed in a coordinate system as shown in the diagram Find the magnitude of the y coordinate of the image if an object is placed at origin 20 cm

mirror how would the screen have to be moved A 4 5 cm needle is placed 12 cm away from a convex mirror of focal length 15 cm Give the location of the image and the magnification Describe what happens as the needle is moved farther from the mirror parent

Aakash Rank Booster Test Series for NEET 2020 32 A thin mica sheet of thickness 2 x 10 6 m and refractive index u 1 5 is introduced in the path of the waves from upper slit in YDSE The wavelength of the wave used is 5000 A The central bright maximum will shift 1 2 fringes upwards 2 2 fringes downwards 3 10 fringes upwards 3

A compound microscope consist of an objective of focal length 2 cm and an eye piece of focal length 5 cm seperated by a distance of 15 cm How far should an object be placed from the objective in order to obtain in the final image at infinity 1 5 cm 2 10 cm 3 2 5 cm 4 None

An object is placed at a distance of f 2 from a conve lens of focal length f The image will be 1 At one of the foci virtual and double of its size 2 At 3f 2 real and inverted 3 At 2f virtual and erect 4 At f real and inverted

14 A concave mirror is placed on a horizontal table with its axis directed vertically upwards Let O be the pole of the mirror and C its centre of curvature A point object is placed at C It has a real image also located at C If the mirror is now filled with water the image will be 1 real and will remain at C 2 real and located at a point between C and 3 virtual and located at a point between C and O 4 real and located at a point co

A convex lens is used to form an image of an object on a wall By moving the lens 40 cm nearer to the wall a sharp image is again obtained having one quarter the length of the first image Focal length of lens is 40 cm 40 cm 20 cm 80 3 cm

An achromatic convergent system of focal length 20 cm is made of the lenses in contact of materials having dispersive powers in the ratio 1 2 Their focal length must be respectively 1 10 cm 20 cm 2 20 cm 10 cm 3 10 cm 20 cm 4 20 cm 10 cm

The maximum value of index of refraction of a material of a prism which allows the passage of light through it when the refracting angle of the prism is A is A 1 2 40 4 2 1 005 2 1 sin cos V 2 3 1 tan 2 A 4 2 1 cot A 2

Match the corresponding entries of column 1 with column 2 Where m is the magnification produced by the mirror Column 1 A B C D m 2 1 2 m N N m 2 m 1 2 a b c d Column 2 Convex mirror Concave mirror Real image Virtual image 1 Ab and c B b and c C b and d Da and d 2 Aa and c Ba and d Ca and b D cand d 3 Aa and d B b and c Cb and d D b and c 4 Ac and d Bb and d Cb and c Da and d

For paraxial rays show that the focal length of a spherical mirror is one half of it radius of curvature Explain about total internal reflecting prisms with suitable ray diagrams

Statement1 Bending of light due to obstruction by opaque objects is called the phenomenon of Refraction Statement2 Different speeds are experienced by a ray of light while it travels in different mediums O Both Statements are true Statement 1 is true and statement 2 is false Statement 1 is false and statement 2 is true Both statements are false

A point object is placed on the axis of the concave mirror at a distance of 60 cm from the focal point of the mirror Its image is formed at the point of object itself then focal length of mirror is O 15 cm O 30 cm 60 cm 120 cm

illustration 9 A converging lens of focal length 15 cm and a converging mirror of focal le 20 cm are placed with their principal axes coinciding Point object is placed at a distance 12 from the lens Refracted ray from the lens gets reflected from the mirror and again refracte the lens It is found that the final ray coming out of the lens is parallel to the principal axis the distance between the mirror and the lens Solution Focal point of lens F F Focal point of mirror N LM TXA M Applying Gauss formula to le 1 1 1 V 12 x 15 12 15 u f Using cartesian sign conventi 60 cm P

A point object O is placed in front of a gla u 3 2 rod having spherical end of radius c curvature 30 cm The image would be forme at 0 Air Glass 15cm 30 cm 1 30 cm left of surface 2 Infinity 3 1 cm to the right of surface 4 18 cm to the left of surface

A small pencil of length 10 cm is k along the axis of a concave mirror of rad of curvature 40 cm with its tip touching mirror The size of pencil s image wo appears to be 1 5 cm 2 10 cm 3 20 cm 4 infinite loun dar

The diagram shows a concavo convex lens of RI What is the condition on the refractive indices so that the lens is diverging 2R 1 2u3u 1 3 3 2 F Hz R 2 2 3 4 None of these

1 10 10 cm 2 10 20 cm 3 20 10 cm 4 20 20 cm A convex lens forms an image at a distance 10 cm when a parallel beam of light is incident on it Find the position s of a concave mirror of radius of curvature 5 cm such that the final image is formed at infinity 1 At a distance of 10 cm from the lens 2 At a distance of 15 cm from the lens 3 At a distance of 5 cm from the lens 4 Both 1 and 2

has a focal length f and power P It is cut into two symmetrical halves b by a plane containing the principal axis The two pieces are recombined as shown in figure c The power of new combination is a b DU c

For CORRECT answer you will be awarded 4 Marks and for WRONG answer there is a negative marking of 1 Mark No ma Locate the position of the point P as seen by the eye in the figure below Eye 6cm 1 4 cm above P 2 10 cm above P 3 15 cm above P 4 5 cm above p 30 cm 20 cm 20 cm P 5cm 4cm p 4

Locate the position of the point P as seen by the eye in the figure below O4 cm above P 10 cm above P 30 cm 20 cm 20 cm Scm H em 6cm 2 Eye 4 54

101 A light ray takes t time to travel a distance x in air The same light ray takes 8t time to travel 3x distance in a medium then the critical angle when the light ray is passing from the medium to air is 1 45 2 60 3 sin 8 1 4 sin 3

Unit vector along a ray of light that is incident on a plane mirror is 3 k and unit vector along the normal to the mirror at the point incidence is 3 unit vector along the reflected ray can be expressed as

3 k and unit vector along the normal to t Unit vector along a ray of light that is incident on a plane mirror is 3 unit vector along the reflected ray can be expressed as mirror at the point incidence is

An object is placed on the principal axis of a concave mirror of focal length 10 cm at a distance 8 0 cm from the pole The image is formed at a distance of Nx10 cm from the pole of mirror determine N Write an answer

Real and inverted image of an object is formed at a distance d 40 cm from the object The size of the image is half of that of object List 1 d 1 The nature of lens used should be 2 Focal length of the lens 3 Distance of object from the lens 4 If mirror were used then nature of mirror should be List 2 A Concave B Convex C 80 3 cm D 80 9 cm

Q10 A beam of light strikes a glass sphere of diameter 15 cm converging towards a point 30 cm behind the pole of the spherical surface Find the position of the image if refractive index of glass is 1 5

An object 20 cm in front of a lens forms a sharp image on a film 10 cm behind the lens A glass plate 6 cm thick of refrac tive index 1 50 is placed between lens and film with its plane faces parallel to film At what distance from lens should object be shifted to be in sharp focus on film b 22 cm a 18 cm c 15 cm d 16 cm

Power P of a lens is given by reciprocal of focal length f of the lens i e P When f is in metre P is in dioptre When a number of thin lenses of power P1 P2 P3 are hold in contact with one another the power of combination is given by algebraic sum of the powers of all the lens i e P P P P3 With the help of the following passage choose the most appropriate alternative for each of the following question Two thin lenses are in contact and the focal length of the combination is 80 cm If the focal length of one lens is 20 cm the focal length of the other would be Select an answer A B C D 26 7 cm 60 cm 80 cm 20 cm

Match the entries of column I with the entries of column II Considering all the cases with refrence to real objects and virtual objects also List 1 1 Plane mirror 2 Concave mirror 3 Convex lens 4 Convex mirror Answer 1 2 3 A A A List 2 B B B B A Virtual image B Real image C Erect image D Inverted image C C C D D D D

The light reflected by a plane mirror may form a real image Select an answer A B C D if the rays incident on the mirror are converging if the rays incident on the mirror are diverging if the object is placed very close to the mirror under no circumstances

A farsighted person s least distance of distinct vision is 0 5 m The power of the lens that should be prescribed to enable him to a read a book held at 0 25m is x diopter Find the value of x Write an answer

D A film of refractive index n and thickness t is deposited on a substrate of refractive index p such that p n Light of wavelength l is falling normally on film Condition for maxima in reflected light is given by Point 2nt ml where m 0 1 2 2nt 2m 1 1 2 where m 0 1 2 None of these