Question 2 :
By which optical phenomena the splitting of white light into seven constituent colours occur?<br>
Question 5 :
Intensity of light ray in a directionafter scattering by small particles (smaller than wavelength):
Question 6 :
Which of the following quantities changes during the process of scattering?
Question 7 :
Some stars appear red in colour and some blue in colour. Which one of the statements is true?<br>
Question 8 :
Which of the following observations cannot be explained by Tyndall Effect?
Question 9 :
Intensity of light ray in a directionafter scattering by small particles (smaller than wavelength):
Question 10 :
The split of white light into its constituent colours by a triangular prism is called ________ .<br/>
Question 12 :
A man can see vertical lines but he is unable to see the horizontal lines placed at the same distance. What type of lens he should use?
Question 15 :
The bluish colour of water in deep sea is due to:<br/>
Question 18 :
Why astronauts see dark sky in space unlike blue sky on earth:
Question 22 :
When a white light ray falls on a prism, the ray at its first surface suffers:<br>
Question 24 :
State whether true or false :Myopia is caused due to the high converging power of the eye lens.
Question 26 :
Which colour of light is scattered the most(maximum) in the atmosphere?
Question 27 :
The path of beam of light becomes _____ in a colloidal solution.
Question 28 :
When white light is passed through two consecutive prisms, the resultant will be:
Question 29 :
The least distance of distinct vision for a defective eye is $75$ cm. What should be the focal length of the lens which will be used to read a book clearly at $25$ cm?
Question 30 :
Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?<br/>
Question 31 :
A defect, in which a person suffering from is unable to see in all directions equally well, is:
Question 33 :
What are the colours of the Sun observed most during sunrise/sunset and noon? <br/>
Question 37 :
Some stars appear red in colour and some blue in colour. Which one of the statements is true?<br>
Question 38 :
Suppose the vitreous humour of the eye dries off. Then what will be its effect on our eyes?
Question 39 :
Fine beam of light entering through a small hole in a dark room illuminates the particles in its path. Identify the effect associated with this process.<br/>
Question 42 :
Why astronauts see dark sky in space unlike blue sky on earth:
Question 43 :
Which of the following lens is used to minimise hypermetropia ?
Question 46 :
Name the prism required for obtaining the spectrum of ultraviolet light:<br/>
Question 47 :
As the thickness of the atmosphere increases colour of scattered light is found in ________order.
Question 48 :
For the angle of minimum deviation of a prism to be equal to its refracting angle, the prism must be made of a material whose refractive index lies between:
Question 50 :
What are the colours of the Sun observed most during sunrise/sunset and noon? <br/>
Question 51 :
During scattering of light, the amount of scattering is inversely proportional to ________ of wavelength of light.
Question 52 :
During scattering of light, the amount of scattering is inversely proportional to ________ of wavelength of light.
Question 54 :
Larger particles scatter light at the ____ end of the spectrum the least. <br/>
Question 58 :
Assertion: Bluish colour predominates in a clear sky, since blue has a shorter wavelength and is scattered strongly.
Reason: Blue has the shortest wavelength among all colours.
Question 59 :
Assertion: The setting sun appears to be red.
Reason: Scattering of light is directly proportional to the wavelength.
Question 60 :
At sun rise or at sun set the sun appears to be reddish while at mid day it looks white. This is because
Question 63 :
Which of the following phenomena cannot be explained by scattering of light ?
Question 64 :
Assertion: By roughening the surface of a glass sheet its transparency can be reduced. <br>Reason: Glass sheet with rough surface absorbs more light.
Question 65 :
Assertion: A piece of red glass is heated till it glows in dark. The colour of glowing glass would be orange.
Reason: Red and orange is complementary colours.
Question 66 :
In a beaker containing colloidal solution of sodium thiosulphate and a drop of con. sulphuric acid, light observed from side of beaker is:
Question 67 :
When is the direction of scattered light independent of the wavelength?
Question 70 :
Assertion: The setting sun appears to be red.
Reason: Scattering of light is directly proportional to the wavelength.
Question 71 :
Which of the following phenomena cannot be explained by scattering of light ?
Question 73 :
Assertion: The setting sun appears to be red. <br>Reason: Scattering of light is directly proportional to the wavelength.
Question 74 :
Assertion: Incoming light reflected by earth is partially polarized.
Reason: Atmospheric particle polarize the light.
Question 77 :
Larger particles scatter light at the ____ end of the spectrum the least. <br/>
Question 78 :
In a beaker containing colloidal solution of sodium thiosulphate and a drop of con. sulphuric acid, light observed from side of beaker is:
Question 83 :
Assertion: A Diamond sparkles more than a glass imitation cut to the same shape.
Reason: The refractive index of diamond is less than that of glass.
Question 84 :
At sunrise or sunset, the sun appears to be reddish white. This is because :
Question 86 :
Assertion: Fine particles in atmosphere scatter the light of shorter wavelength more.
Reason: Sky appears blue.
Question 88 :
At sunrise or sunset, the sun appears to be reddish white. This is because :
Question 89 :
Assertion: Incoming light reflected by earth is partially polarized.
Reason: Atmospheric particle polarize the light.
Question 90 :
Assertion: A Diamond sparkles more than a glass imitation cut to the same shape.
Reason: The refractive index of diamond is less than that of glass.
Question 91 :
Assertion: In the absence of atmosphere the sky would appear black.<br/>
Reason: Atmosphere scatters the light and hence we get blue colour.
Question 92 :
Assertion: By roughening the surface of a glass sheet its transparency can be reduced. <br>Reason: Glass sheet with rough surface absorbs more light.
Question 95 :
Assertion: The setting sun appears to be red. <br>Reason: Scattering of light is directly proportional to the wavelength.
Question 97 :
When is the direction of scattered light independent of the wavelength?
Question 100 :
At sun rise or at sun set the sun appears to be reddish while at mid day it looks white. This is because
Question 102 :
Myopia or near sightedness is a defect of eyes in which<br>
Question 103 :
The defective condition of accommodation of the eye in which distant objects are clearly seen but near objects are indistinct is<br>
Question 104 :
The process of re-emission of absorbed light in all directions with different intensities by the atom or molecule is called ____________.
Question 105 :
Two point white dots are 1 mm apart on a black paper. They are viewed by eye of diameter $3\ mm $.<br/>Approximately, what is the maximum distance at which these dots can be resolved by the eye?<br/>[ take wavelength of light >500nm]
Question 107 :
In old age farsightedness is a defect of eye in man, in which
Question 108 :
A person is wearing spectacles with concave lenses for correcting vision. While not using the glasses, the image of a distant object in his case will be formed<br>
Question 110 :
When the light rays converge at a point in front of the retina and then divert to form a blurred image on it, the defect is known as<br>
Question 112 :
The angular magnification of telescope is $30$. If all the light which passes through objective lens of diameter $80 cm$ also passes through eye piece lens then find out diameter of eye piece lens.
Question 114 :
One of the following is not an example of incomplete sex-linkage
Question 115 :
A normal eye is not able to see objects closer than $25$cm because?
Question 116 :
A beam of light passing from air enters into the glass. Identify which of the following statements is true?<br/>
Question 117 :
A ray of light is incident perpendicularly on a glass slab. The angle of incidence is :
Question 118 :
An object 20 cm from lens, has a virtual image at 10 cm from the object. The power of the lens is
Question 120 :
A unit vector along the incident ray of light is $\hat{i}$. The unit vector for the corresponding refracted ray of light is $\hat{r}\cdot \hat{n}$, a unit vector normal to the boundary of the medium and directed towards the incident medium. If $\mu$ is the refractive index of the medium, then Snell's law (second law) of refraction is :
Question 121 :
Which of the following is not a characteristic of image formed by a Concave lens ?
Question 122 :
In case of a real and inverted image, the magnification created by the mirror is<br/>
Question 123 :
If an object is placed $10\ cm$ infront of a concave mirror of focal length $20\ cm,$ the image will be
Question 125 :
The distance between an object and its real image produced by a converging lens is $0.72\ m$. The magnification is $2$. What will be the magnification when the object is moved by $0.04\ m$ towards the lens?
Question 126 :
If an object is placed at '$C$' of a concave mirror, the position of the image is ______
Question 128 :
The power of a lens being $+4$ dioptres suggests that it is a
Question 130 :
When the height of the image is less than the height of the object, then magnification will be
Question 131 :
A person sees his virtual image by holding a mirror very close to the face. When he moves the mirror away from his face, the imagebecomes inverted. What type of mirror he is using
Question 132 :
What is the power of the lens, if the far point of a short sighted eye is $200\ cm$?
Question 133 :
A student obtained a sharp inverted image of a distant tree on a screen placed in front of the concave mirror. He then removed the screen and tried to look into the mirror. He would now see:
Question 134 :
If the power of a lens is $0.1\;D$, its focal length is
Question 137 :
Due to refraction, when seen from outside,a coin placed under water in a bowl, appears to
Question 138 :
State whether true or falseA convex mirror is used for obtaining a real and magnified image.
Question 139 :
"Value of refractive index remains same for light rays with different wavelength and for a particular material"
Question 141 :
The heat of sun focussed by a convex lens on a piece of paper is capable of
Question 143 :
The ratio of the size of the image to the size of the object is known as
Question 145 :
The image formed by the given convex mirror when it is inside focal distance is:
Question 146 :
A camera is an optical instrument which makes use of a :
Question 147 :
In case of a virtual and erect image, the magnification created by the mirror is
Question 148 :
A real image, equal in size to the object, is obtained when the object is placed at the centre of curvature in front of which mirror?
Question 149 :
When a drop of oil is spread on a water surface, it displays beautiful colours in daylight because of :
Question 150 :
When the object is at focus of a concave mirror, the image is formed at
Question 151 :
$ \dfrac{\sin i}{\sin r}  =$constant, the value of constant depends upon<br/>a) Pair of media <br/>b) Color of incident light<br/>c) Wave length <br/>d) Refracting nature of material<br/>
Question 152 :
Find the focal length of a convex lens, if its power is +2.0 D.
Question 153 :
The sum of the reciprocals of object distance and image distance is equal to the __________ of a mirror.<br>
Question 154 :
A focal length of a lens is 10 cm. What is power of a lens in dioptre?
Question 155 :
The power of two convex lenses $A$ and $B$ are $8$ diopters and $4$ diopters respectively. If they are to be used as a simple microscope, the magnification of
Question 156 :
Which of the following is not a use of concave lens?
Question 157 :
A wave has velocity v in medium P and velocity 2v in medium Q. If the wave is incident in medium P at an angle of 30, then the angle of refraction will be
Question 158 :
Lens A produces a magnification of -0.8 whereas lens B produces a magnification of +0.8. Which one of the following applies to lenses A and B?
Question 161 :
The magnification of an image by a convex lens is positive only when the project is placed:
Question 164 :
Due to refraction, sunrise appears ______ sun comes to horizon and sunset appears______sun leaves horizon respectively.
Question 166 :
Assertion: Air bubble shines in water.
Reason: Air bubble in water shines due to refraction of light.
Question 167 :
A glass slab is placed in the path of convergent light. The point of convergence of light :
Question 168 :
The magnification of the image when an object is placed at a distance x from the principle focus of a mirror of focal length f is?
Question 169 :
A beam of light passes through a sheet of plastic and out into the air. The beam makes ${\theta}_{1}$ angles with the normal as it passes through the plastic and the angle the beam of light makes with the normal as it passes into the air is ${\theta}_{2}$. The refractive index for air is $1$ and The refractive index for plastic is $2$.<br/>Calculate the value of $\sin{{\theta}_{2}}$, in terms of ${\theta}_{1}$?
Question 170 :
A person needs a lens of power -4.5 D for correction of her vision. What is the focal length of the corrective lens?<br/>
Question 171 :
An object $15 cm$ high is placed $10 cm$ from the optical center of a thin lens. Its image is formed $25 cm$ from the optical center on the same side of the lens as the object. The height of the image is:<br>
Question 172 :
A student performs an experiment to study the nature of the image formed by a convex lens. <br/>Arrange the steps in the proper sequence.<br/>(a) Place the lens on a V-shaped stand.<br/>(b) Place the object at $2F_{1}$.<br/>(c) Place the object between $2F_{1}$ and $F_{1}$.<br/>(d) Determine the focal length of the lens by focusing the lens to a distant object like a tree.<br/>(e) Adjust the position of the screen behind the lens to obtain a clear image and study the nature of the image.<br/>(f) Mark the positions of $F_{1}, 2F_{1}, F_{2}$   and $ 2F_{2}$.<br/>(g) Focus the lens to a distant object like a tree.<br/>(h) Place the object just behind $2F_{1}$.<br/>(i) Place the object at $F_{1}$.<br/>(j) Place the object between $F_{1}$ and optic centre of the lens and observe that the image formed is virtual.<br/>
Question 175 :
A light ray passes from a material of low refractive index to one of high refractive index. Which of the pairs of quantities listed below describes the light ray as it strikes and passes through the interface between the two materials? Match the descriptions below with the statement that <i>best</i> describes the situation.<br/>A part of the light ray remains inside the low refractive index material:<br/>
Question 176 :
The relation between $u, v$ ( u is the object distance and v is the image distance )  and f for mirror is given by:<br/>
Question 177 :
An object $5$ cm tall is placed $1$ m from a concavespherical mirror which has a radius of curvatureof $20$ cm. The size of the image is:<br>
Question 178 :
If the refractive index of water and glass with respect to air are, respectively, $\displaystyle \frac {4}{3}$ and$\displaystyle \frac {3}{2}$then what will be the refractive index of glasswith respect to water?
Question 179 :
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 180 :
A slide projector gives a magnification $10.$ If a slide of dimensions $3$ cm $\times$ $2$ cm is projected on the screen the area of image screen is
Question 182 :
One student uses a lens of focal length $50 \ cm$ and another of $-50\  cm$. What is the nature of the lens and its power used by each of them?<br/>
Question 183 :
Assertion: Magnification of a convex mirror is always positive, but that of a concave mirror may be both positive or negative.
Reason: It depends on the sign convention chosen.
Question 184 :
The image of an object placed in front of a concave mirror of focal length 12 cm is formed at a point which is 10 cm more distant from the mirror than the object. The magnification of the image is:<br/>
Question 185 :
A light of wavelength $6000A^{\circ}$ in air, enters a medium with refractive index $1.5$. Inside the medium its frequency is _________ $Hz$ and its wavelength is ______ $6000 A^{\circ}$.
Question 186 :
Power of a lens is -40 , its focal length is
Question 187 :
For a thin convex lens when the height of the object is doubled than its image, its object distance is equal to __________.
Question 188 :
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 189 :
The time from sunrise to sunset is lengthened by about 4 minutes on the earth because
Question 190 :
A vertical ray of light strikes the horizontal surfaceof water.What is the angle of refraction?
Question 191 :
A ray of light moving along the unit vector $\dfrac{1}{\sqrt5}(\hat { -i  } -2\hat { j } )$ undergoes refraction at an interface of two media, which is the x-z plane. The refractive index for y > 0 is 2 while for y < 0, it is $\sqrt{5}$/2. The unit vector along which the refracted ray moves is
Question 192 :
A person cannot see distinctly objects kept beyond $2$ $m$. This defect can be corrected by using a lens of power:<br/>
Question 193 :
A beam is composed of red and green rays. It is incident obliquely at a point on the face of a rectangular glass slab. When coming out on the opposite parallel face, the red and green rays emerge from :
Question 194 :
An object 20 cm from a concave mirror form an image, double the size of the object, on a screen. How far should the screen be placed from the mirror? 
Question 195 :
Two lenses whose powers are $4D$ and $-2D$ are kept in contact. The power of the compound lens is:
Question 197 :
If an object is placed at a distance of 20cm from the pole of a concave mirror, the magnification of its real image is 3. If the object is moved away from the mirror by 10cm, then the magnification is -1.
Question 198 :
A sound wave is travelling in a medium in which the velocity is $v$. It is incident in the second medium in which the velocity of the wave is $2v$. What should be the minimum angle of incidence in the first medium, so that the wave fails to cross the surface of separation of the two media?
Question 199 :
The magnification produced by a mirror is $+\dfrac{1}{3}.$ Then the mirror is a ____________.
Question 200 :
Two lenses one of focal length $20 cm$. (convex lens) and another of focal length $-15 cm$ (concave lens) are placed in contact. Identify the correct statement.
Question 201 :
A man can see only between $75\ cm$ and $200\ cm$. The power of lens to correct the near point will be
Question 202 :
A beam of monochromatic blue light of wavelength $4200\mathring { A } $ in air travels in water of refractive index ${ 4 }/{ 3 }$. Its wavelength in water will be
Question 203 :
A ray of light is incident on glass slab making an angle of incidence $sin^{-1} \left( \dfrac{\sqrt 3}{2} \right )$. What will be the angle of refraction in glass of refractive index 1.5?
Question 205 :
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 207 :
The image of an object placed on the principal axis of a concave mirror of focal length $12\ cm$ is formed at a point which is $10\ c$ more distance from the mirror than the object. The magnification of the image is
Question 208 :
If the angle of incidence is twice the angle of refraction in a medium of refractive index $\mu$, then the angle of incidence is :
Question 209 :
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 211 :
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 212 :
An object is placed upright on the axis of a thin convex lens at a distance of four focal lengths ($4f$) from the center of the lens. An inverted image appears at a distance of $\dfrac{4}{3} f$ on the other side of the lens. What is the ratio of the height of the image of the height of the object?
Question 213 :
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 214 :
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 215 :
When light passes from air to glass, it experiences a change of:
Question 216 :
The final image in an astronomical telescope is _______ the original object . Fill in the gap.<br/>
Question 217 :
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 218 :
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 219 :
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 220 :
The image obtained while finding the focal length of convex lens is...................
Question 221 :
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 222 :
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 223 :
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 224 :
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 225 :
The distance between an object and its doubly magnified image by a concave mirror is: [ Assume $f$ = focal length]
Question 226 :
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 227 :
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 $z< 0$ 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 228 :
What happens when a ray of light is made to fall on a mirror along the normal?<br/>
Question 229 :
The angle between the incident ray and the normal is called ________.<br>
Question 230 :
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?
Question 231 :
The diameter of the reflecting surface of spherical mirror is called ..............
Question 232 :
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 233 :
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 234 :
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 235 :
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 $20\  cm$ is placed in between the convex lens and the image, at a distance $26\  cm$ from the convex lens, size of the new image is:
Question 236 :
The glancing angle of incidence is $10^{\circ}$. What will be the glancing angle of reflection?
Question 237 :
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 238 :
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 239 :
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 240 :
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 241 :
When a light of wavelength $4000$ $\displaystyle \overset { \circ  }{ A } $ 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 $\displaystyle \frac { 5 }{ 2 } $ and $\displaystyle \frac { 4 }{ 3 } $ respectively.
Question 242 :
Two thin lenses of power $+3.5D, -2D$ are placed in contact. Find the power of lens combination.
Question 244 : In the table below, column I lists various mirrors  and lenses and column II their uses, qualities or properties.<br/><table class="wysiwyg-table"><tbody><tr><td>column  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 </td><td>D. 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 245 :
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>($\displaystyle { \mu }_{ g } = 1.5,{ \mu }_{ w } = \frac { 4 }{ 3 }$)
