Question 2 : When a drop of oil is spread on a water surface, it displays beautiful colours in daylight because of :

Question 3 : When a ray of light passes from an optically less dense medium to a more dense medium, it :

Question 4 : Which of the following is not a characteristic of the image formed by Convex lens ?

Question 5 : Which of the following is not a use of concave lens?

Question 6 : Choose the correct answer:<br>The nature of image formed by convex mirror is:

Question 8 : A ray passing with which part of a lens emerges undeviated ?

Question 9 : The focal length of a lens can be expressed in :

Question 10 : The focal length of a convex lens is $25cm$. Find its power with sign.<br/>

Question 11 : If the light moving in a straight line bends by a small but fixed angle, it may be a case of<br>$(i)$reflection<br>$(ii)$refraction<br>$(iii)$diffraction<br>$(iv)$dispersion<br>

Question 12 : A ray of light is incident on the surface of transparent medium at an angle of $45^o$ and is refracted in the medium at an angle of $30^o$. What will be the velocity of light in the transparent medium ?&#160;<br/>

Question 13 : In case of a real and inverted image, the magnification of a mirror is:

Question 14 : Identify the phenomenon due to which a converging lens forms an image :

Question 17 : Due to refraction, sunrise appears ______ sun comes to horizon&#160;and sunset appears______sun leaves horizon respectively.

Question 18 : Choose the correct statement(s) related to the motion of object and its image in the case of&#160; mirrors.

Question 19 : Which of the following term is not associated with a lens?

Question 22 : A focal length of a lens is 10 cm. What is power of a lens in dioptre?

Question 23 : <br>Which is the human organ which behaves like an optical instrument having lens and a screen?

Question 24 : A ray of light strikes the glass slab at an angle of $50^o$. Then the angle of incidence will be _____.

Question 25 : The mirror used in automobiles to see the rear field of view is

Question 26 : If $f$ is the focal length of a lens, then the power of the lens is equal to

Question 27 : If in a plano-convex lens, the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm, then the refractive index of the material of lens will be

Question 28 : The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?

Question 29 : When a ray of light passes through a rectangular glass slab, the angle of emergence

Question 31 : The power of a lens is $+2.0D$. Find its focal length and state the kind of the lens.<br>

Question 32 : The power of a lens whose focal length is one metre is ______ dioptre.

Question 33 : Four students perform an experiment on tracing the path of a ray of light passing through a rectangular glass slab. Their individual observations are:<br>identify the incorrect observation and correct them.<br>

Question 34 : The heat of sun focussed by a convex lens on a piece of paper is capable of

Question 35 : A thin film of thickness i and index of refraction 1.33 coats a glass with index of refraction 1.50. What is the least thickness/that will strongly reflect light with wavelength 600 nm incident normally?

Question 36 : When the face is very close to the spoon the image formed by the outside bulged part?

Question 37 : When a ray of light passes through a rectangular slab, made up of some transparent material other than glass, the emergent ray is

Question 43 : The power of a convex lens of focal length $2$ metre will be:

Question 44 : Which of the following is not a characteristic of image formed by a Concave lens ?

Question 46 : The relation between the linear magnification $m,$ the object distance $u$ and the focal length $f$ is

Question 47 : Which of the following term is not associated with a lens ?

Question 50 : State whether the following statement is True or False.A concave mirror&#160;always forms a real image

Question 51 : Calculate the focal length of a convex lens of power 2D.<br/>

Question 52 : A virtual image larger than the object can be produced by a :

Question 53 : The image of an object is formed by a convex lens. When that object is placed beyond the focal length is -

Question 54 : A lens of focal lengths $20 cm$ produces a real image of a stationary object having magnification $2$. Find the distance by which the lens should be moved so that it produces a virtual image of&#160;the same magnification.<br/>

Question 56 : A convex lens produces a double size real image when an object is placed at a distance of $18$ cm from it. Where should the object be placed to produce a triple size real image?

Question 57 : A object is placed at 30 cm on the principle axis of the convex lens from the lens and an image is formed 60 cm from the lens. If focal length of the lens is 20 cm then calculate the magnification.

Question 59 : One student uses a lens of&#160;focal length $50 \ cm$ and another of $-50\&#160; cm$. What is the nature of&#160;the lens and its power used by each of them?<br/>

Question 60 : The focal length of a concave mirror is $50\ cm.$ Where an object beplaced so that its image is two times and inverted

Question 61 : A glass slab is placed in the path of a beam of convergent light; the point of convergence of light

Question 62 : The frequency of a light wave in a material is $2\times 10^{14}$Hz and wavelength is $5000\overset{o}{A}$. The refractive index of material will be

Question 63 : A ray of light travels from ethanol into air. If the angle of incidence of the ray at the boundary is $30^0$ and the refractive index of ethanol is 1.36, what is the angle of refraction of the ray as it emerges out of ethanol?

Question 64 : An object placed at a distance of <b>16 cm</b> from first principal focus of convex lens, produces a real image at a distance of <b>36 cm&#160;</b>from its second principal focus. Then the focal length of the lens is :

Question 65 : The relation between $u, v$ ( u is the object distance and v is the image distance )&#160; and f for mirror is given by:<br/>

Question 66 : The far point of a myopic person is 40 cm. To see the distantobjects clearly, the focal length and the power of the lensused should be:

Question 67 : An object is at 0.08 m from a magnifying lens and&#160;the image is formed 40 cm from the lens. The magnification produced is&#160;

Question 69 : A ray of light is travelling through a medium of refractive index $\dfrac {1}{\sqrt {2}}$ with respect to air. When it is incident on the surface making an angle $45^{\circ}$ with the surface, which of the following will take place?

Question 70 : The focal length of a plano-convex lens is equal to its radius of curvature. The value of the refractive index of its material is

Question 73 : The focal length of a concave lens is 2 m, calculate the power of the lens.

Question 74 : The difference in the number of wavelengths,&#160;when yellow light propagates through air and&#160;vacuum columns of the same thickness is one.&#160;The thickness of the air column is :(Refractive index of air $\mu _{a}=$1.0003 ;&#160;Wavelength of yellow light in vacuum $= 6000A^{\circ}$)<br/>

Question 75 : A diverging meniscus lens has a focal length of -20 cm. If the lens is held 10 cm from the object, the magnification is :

Question 76 : The focal length of a concave mirror is f and the distance from the object to the principal focus is p. The ratio of the size of the real image to the size of the object is:<br/>

Question 77 : Let the $\mathrm{x}-\mathrm{y}$ plane be the boundary between two transparent media. Medium 1 in $\mathrm{z}\geq 0$ has a refractive index of $\sqrt{2}$ and medium 2 with $\mathrm{z}&lt; 0$ has a refractive index of $\sqrt{3}$. A ray of light in medium 1 given by the vector $\vec{\mathrm{A}}=6\sqrt{3}\hat{\mathrm{i}}+8\sqrt{3}\hat{\mathrm{j}} + 10\hat{\mathrm{k}}$ is incident on the plane of separation. The angle of refraction in medium 2 is<br>

Question 78 : A ray of light falls into a medium of $R.l.\mu$ from vacuum. The angle of incidence is found to be twice the angle of refraction. Then, the angle of incidence is

Question 79 : A fish is looking at a $1.0m$ high plant of the edge of the pond. Will the plant appear shorter or taller than its actual height, to the fish

Question 80 : We want a mirror that will make an object look larger. What combination of image and object distances (from the mirror) will accomplish this?

Question 81 : Two thin lenses, when in contact, produce a combination of power$+10D$. When they are $0.25m$ apart, the power reduces to $+6D$. The focal lengths of the lenses (in m) are

Question 82 : The linear magnification for a spherical mirror is the ratio of the size of the image to the size of the object, and is denoted by m. Then m is equal to (symbols have their usual meanings)

Question 83 : A $2 cm$ tall object is placed perpendicular to the principal axis of a convex lens of focal length $1 cm$. If the object distance is $1.5 cm$. Find the magnification.

Question 84 : In aerial mapping a camera uses a lens with a $100\ cm$ focal length. The height at which the airplane must fly,so that the photograph of a $1\ km$ long strip on theground fits exactly on the $20\ cm$ long filmstrip of thecamera, is

Question 85 : Assertion: The focal length of the concave mirror is $f$ and distance of the object from the focus is $u$. The magnification of the image will be $f/u$ Reason: Magnification=$\dfrac{size\ of\ object}{size\ of \ image}$

Question 86 : A parallel beam of white light is incident normally on a water film $1.0 \times 10^{-4}$ cm thick. Find the wavelength in the visible range $(400\ nm-700\ nm)$ which are strongly transmitted by the film. Refractive index of water $= 1.33$.

Question 87 : Images formed by which of the following arrangement isnot Virtual and erect ?

Question 88 : An under-water swimmer cannot see very clearly even in absolutely clear water because of:

Question 89 : A concave lens always gives a virtual image. In opticallenses worn by humans which of the following statementsis true ?

Question 90 : The lens of a simple magnifier has a focal length of 2.5 cm. Calculate the angular magnification produced when (a) the image is at least distance of distinct vision, and (b) infinity.

Question 91 : When a ray of light traveling from vacuum to a&#160;medium of refractive index $\mu $, the angle of&#160;incidence is twice the angle of refraction. The incident angle is :<br/>

Question 93 : The least distance of vision of a longsighted person is $60\ cm$. By using a spectacle lens, this distance is reduced to $12\ cm$. The power of the lens is

Question 94 : The angle between reflected and refracted beams is $90^0$in the water air interface. The angle of incidence in water is

Question 95 : An object of length $4 \ cm$ is placed in front of a concave mirror at a distance of $30 \ cm$. The focal length of mirror is $15\ cm$.&#160;What will be the length of image?

Question 96 : If an object is placed at a distance of 20cm from the pole of a concave mirror, the&#160;magnification of its real image is 3. If the object is moved away from the mirror by 10cm,&#160;then the magnification is -1.

Question 97 : The power of a lens is a measure of its degree of

Question 98 : A square card of side length 1 mm is being seen through a magnifying lens of focal length 10 cm. The card is placed at a distance of 9 cm from the lens. The apparent area of the card through the lens is

Question 99 : A ray of light is incident from one medium $(\mu = 1.5)$ into another medium. If the angle of incidence and refraction are, respectively,$60$and$45$, thenwhatwill be the refractive index of the denser medium?

Question 100 : A light ray travels at some angle (not head on) from water in a rectangular aquarium, through the glass side, and out into the air. The indices of refraction for water, glass, and air are $1.33$, about $1.6$, and $1.0$, respectively.<br>Rank the materials according to the angles made by the light ray with the normal in each, greatest first

Question 101 : Image of an object at infinity is formed by a convex lens of focal length $30 \ cm$ such that the size of the image is $2 \ cm$. If a concave lens of focal length $20\&#160; cm$ is placed in between the convex lens and the image, at a distance $26\&#160; cm$ from the convex lens, size of the new image is:

Question 102 : A spherical convex surface separates object and image space of refractive index $1$ and $4/3$ respectively. If radius of curvature of the surface s $0.1\ m$, its power is

Question 103 : The glancing angle of incidence is $10^{\circ}$. What will be the glancing angle of reflection?

Question 104 : A ray of light going towards the centre of curvature of a convex mirror ............

Question 105 : The angle between the incident ray and the normal is called ________.<br>

Question 106 : A short linear object of length $b$ lies along the axis of a concave mirror of focal length $f$ at a distance $u$ from the pole of the mirror. The size of the image is approximately equal to:<br/>

Question 107 : Two thin lenses of power $+3.5D, -2D$ are placed in contact. Find the power of lens combination.

Question 108 : In vacuum, to travel distance 'd', light takes time 't' and in medium to travel distance $'5d'$, it takes time 'T'. The critical angle of the medium is.<br>

Question 109 : What happens when a ray of light is made to fall on a mirror along the normal?<br/>

Question 110 : A short linear object of length $b$ lies along the axis of a concave mirror of focal length $f$ at a distance u from the pole of the mirror. The size of the image is approximately equal to :<br>

Question 111 : An object is placed at $30$ cm distance from a concave mirror of focal length $20$ cm, then nature, magnification of the image will be:

Question 112 : A symmetric double convex lens is cut in two equal parts by a plane containing the principal axis. If the power of the original lens was 4 D, the power of a divided lens will be

Question 113 : The diameter of the reflecting surface of spherical mirror is called ..............

Question 114 : The final image in an astronomical telescope is _______ the original object&#160;. Fill in the gap.<br/>

Question 115 : A water film is formed on a glass-block. A light ray is incident on water film from air at an angle of$\displaystyle { 60 }^{ \circ }$ with the normal. The angle of incidence on glass slab is<br>($\displaystyle { \mu }_{ g } = 1.5,{ \mu }_{ w } = \frac { 4 }{ 3 }$)

Question 116 : The distance between an object and its doubly magnified image by a concave mirror is: [ Assume $f$ = focal length]

Question 117 : When a light of wavelength $4000$ $\displaystyle \overset { \circ &#160;}{ A }&#160;$ in vacuum travels through the same thickness in diamond and water separately, the difference in the number of waves is $200$. Find the thickness, if refractive indices of diamond and water are&#160;$\displaystyle \frac { 5 }{ 2 }&#160;$ and&#160;$\displaystyle \frac { 4 }{ 3 }&#160;$ respectively.

Question 118 : Air has refractive index $1.0003$. Find the thickness of air column which will contain one more wavelength of yellow light of $6000$ $A^0$ than in same thickness of vacuum.

Question 120 : Let the x-z plane be the boundary between two transparent media. Medium $1$ in $z\ge 0$ has a refractive index of $\sqrt { 2 } $ and medium $2$ with $z&lt; 0$ has refractive index of $\sqrt { 3 } $. A ray of light in medium $1$ given by the vector $\vec { A } =6\sqrt { 3 } \hat { i } +8\sqrt { 3 } \hat { j } -10\hat { k } $ is incident on the plane of separation. The angle of refraction in medium $2$ is:

Question 121 : A flim projector magnifies a flim of area $100 $ square centimeter on screen. If linear magnification is $4$ then area of magnified image on screen will be-

Question 122 : A point object is placed on the principal axis of the convex lens of focal length 20cm at a distance 40 cm to the left on it. The diameter of the lens is 10cm. If the eye is placed 60cm to the right of the lens at a distance h below the principal axis, then max value of 'h' to see the image is

Question 123 : A concave shaving mirror has a radius of curvature of 35.0 cm. It is positioned so that the (upright) image of a mans face is 2.50 times the size of the face. How far is the mirror from the face?

Question 124 : The image obtained while finding the focal length of convex lens is...................

Question 125 : The focal length of a thin biconvex lens is 20 cm. when an object is moved from a distance of 25 cm in front of it to 50 cm, the magnification of its image changes from $m_{25}$ to $m_{50}$. The ratio of $m_{25}$ to $m_{50}$ is :

Question 126 : In the table below, column I lists various mirrors &#160;and lenses and column II their uses, qualities or properties.<br/><table class="wysiwyg-table"><tbody><tr><td>column &#160;I</td><td>Column II</td></tr><tr><td>I. Plane mirror</td><td>A. Feels thinner in the middle.</td></tr><tr><td>II. Concave mirror</td><td>B. Always forms virtual image.</td></tr><tr><td>III. Convex mirror</td><td>C. Always forms virtual image of smaller size.</td></tr><tr><td>IV. Concave lens&#160;</td><td>D.&#160;Is used by dentists to examine teeth.</td></tr><tr><td>V. Convex lens</td><td>E. Can be used as reading glass.<br/></td></tr></tbody></table>The correct matching is:

Question 127 : Aconvex lens of radii of curvature 20 cm and 30 cm respectively. It is silveredat the surface which has smaller radius of curvature. Then it will behave as $(\mu_g\, = \, 1.5)$

Question 128 : A $4.5 cm$ needle is placed $12 cm$ away from a convex mirror of focal length $15 cm$. Find the location of the image and the magnification.

Question 129 : A small object of linear dimension $x$ lies on the axis of an optical mirror of local length $f$ at a distance $a$ from mirror. The linear dimension of image:

Question 130 : The reflecting surface is given by $y = \dfrac{10L}{\pi} \sin \dfrac{\pi x}{5L}$. The co-ordinates of the point where a horizontal ray becomes vertical after reflection is:

Question 131 : A $2.5$ dioptre lens forms a virtual image which is $4$ times the object placed perpendicularly on the lens. Then the required distance of the object from the lens is .

Question 132 : An image of a bright square is obtained on a screen with the aid of a convergent lens. The distance between the square and the lens is $40\ cm$. The area of the image is nine times larger than that of the square. Select the correct statement(s).

Question 133 : The magnitude of focal length of a concave mirror is $f$. An object is placed at a distance $x$ from the focus and forms a real image. The magnification is:<br/>

Question 134 : Three convex lenses are available having focal lengths of $4 cm, 40 cm$ and $4 m$ respectively. Which one could be used as magnifying glass?