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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
The image formed by a plane mirror is ______ in nature. |
| Answer» Correct Answer - virtual | |
| 152. |
A ray of light is incident on a plane mirror at an angle of 30°. What is the angle of reflection? |
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Answer» The angle of reflection will be 30 degree. This is by the law of reflection that angle of incidence is equal to the angle of reflection. |
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| 153. |
A ray of light is incident normally (perpendicularly) on a plane mirror. Where will this ray of light go after reflection from the mirror? |
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Answer» When a ray of light is incident normally (perpendicularly) on a plane mirror, the ray reflects and follows the same path. |
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| 154. |
What difference do you notice on looking through the windows in the picture? What causes the difference? The picture shows transperant, opaque, translucent window panes. Spot them. |
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Answer» 1. Through the first window we can see a clear picture of things outside. 2. Second window gives a faint image. 3. Through the third window, we can’t see anything 4. The difference in the image is due to the material of the window panes. 5. The first window pane is transparent. 6. The second window pane is translucent. 7. The third window pane is opaque. |
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| 155. |
How we can see that light travels in straight line. |
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Answer» 1. In the morning or in the afternoon, rays of light enter a slit in a door, window or a small hole in the roof. 2. As these rays of light from the slit or the hole move towards the floor, the dust particles in their way are clearly seen. 3. Due to these particles, the path of light becomes visible to us. 4. Thus we can see that their path is along straight lines. |
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| 156. |
List factors on which shadow depends. |
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Answer» Shadow depends on relative distance between the source of light, the object and the surface on which the shadow is formed. |
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| 157. |
Fill in the blanks. 1. In going from a rarer to denser medium, the ray of light bends …… 2. The mirror used in search light is ……3. The angle of deviation of light ray in a prism depends on the angle of ………4. The radius of curvature of a concave mirror whose focal length is 5 cm is ………5. Large …… mirrors are used to concentrate sunlight to produce heat in solar furnaces. |
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Answer» 1. towards normal 2. concave mirror 3. prism and angle of incident 4. 10 cm 5. concave |
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| 158. |
Light bends as its passes from one medium to another. What is this phenomenon claled ? |
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Answer» Refraction of light. |
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| 159. |
What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray? |
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Answer» As per the laws of reflection The angle of incidence ∠i = angle of reflection ∠r Here as given ∠i + ∠r = 90° ∴ ∠i + ∠i = 90 ° or ∠i = 90/2 = 45 ° Hence angle of incidence of a ray = 45 degree |
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| 160. |
Name the two types of spherical mirrors. |
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Answer» 1. Concave mirror 2. Convex mirror. |
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| 161. |
Light travels fastest in vacuum. Why ? |
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Answer» Light travels fastest in vacuum than any other medium because there is no obstruction to the passage of light in vacuum. |
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| 162. |
A physics teacher asked a student to find how much time does the light take to reach the earth if the distance between the sun and the earth is `150xx10^(6)km`? Teacher also gives an extra input that velocity of light is `3xx10^(8)ms^(-1)`. What would be the answer of the student? |
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Answer» Velocity of light, `c=3xx10^(8)ms^(-1)` Distance of the sun from the earth, `d=150xx10^(6)km`. `=150xx10^(6)xx10^(3)m` `150xx10^(9)m` `:."Velocity"=("distance")/("time (t)")=500s` `=8.33` minute `:.` light takes 8.33 minute to reach the surface of the earth from the sun. |
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| 163. |
The refractive indices of some media are given below:MediumRefractive indexX1.51Y1.72Z1.83w2.42In which of these is the speed of light minimum and maximum, respectively.(a) X-minimum, W-maximum(b) Z-minimum, W-maximum(c) W-minimum, X-maximum(d) X-minimum, Z-maximum |
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Answer» (c) W-minimum, X-maximum |
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| 164. |
How many times is a ray of light reflected by two plane mirrors placed parallel and facing each other? |
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Answer» Infinite number of times. |
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| 165. |
What will be the number of images formed when an object is placed between two parallel plane mirrors facing each other? |
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Answer» Infinite number of images are formed when an object is placed between two parallel plane mirrors facing each other. The object undergoes multiple reflection to produce image of the distant object. The distance between the mirror and the object is inconsiderable in formation of infinite images. No matter how much the distance be, number of images formed will be infinite. |
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| 166. |
Determine the number of images formed when an object is placed between two parallel plane mirrors facing each other. |
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Answer» Infinite number of the image is formed when an object is placed between two parallel plane mirrors facing each other. |
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| 167. |
Two plane mirrors are inclined at an angle of `30^(@)`, the number of images formed are ______. |
| Answer» Correct Answer - 11 | |
| 168. |
The number of images formed of an object placed between two plane mirrors inclined at right angles to each other is: A. two B. five C. one D. three |
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Answer» D. three The relationship between no. of images and angle of mirror is Images = (360 degrees/ angle between the mirrors) – 1 Images = (360 degree/90 degree) – 1 Images = 4 – 1 Images = 3 |
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| 169. |
Explain why, when an object is placed between two plane mirrors inclined at an angle, then multiple images are formed. |
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Answer» Multiple images are formed due to multiple reflection when an object is placed between two plane mirrors at any angle. N= (360/ θ) – 1 Say, the angle is 120 N = (360/120) – 1 N = 3 – 1 N = 2 |
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| 170. |
Suggest a situation where we obtain more than one shadow of an object at a time. |
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Answer» We can obtain more than one shadow of an object if light from more than one source falls on it. [For example during a match being played in a stadium, multiple shadows of players are seen]. |
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| 171. |
Correct the following statements.(i) The colour of the shadow of an object depends on its colour of the object.(ii) Transparent objects allow light to pass through them partially. |
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Answer» (i) The colour of the shadow of an object does not depend on its colour. |
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| 172. |
In a college hostal , a clever warden in order to know what the students are doing in the room in his absence during night he switched off the light in the corridor and watched the room through a glass partition from the corridor. Explain why the objects in the room are more clearly visible when he switched off the corridor lights than when there is light in the corridor. |
| Answer» Light from the corridor is reflected by the glass pane separating it from the dark room. This reflected light enters our eye along with the light from inside the dark room. Since reflected light is more than the light from the room and also more intense, we cannot see the things inside the room. When the lights in the corridor are switched off, the light from the room now enters our eyes and the visibility improves. | |
| 173. |
Three torches A, B and C shown in Fig. 11.7 are switched on one by one. The light from which of the torches will not form a shadow of the ball on the screen. |
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Answer» The light of torch at position C will not form a shadow of the ball on the screen. |
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| 174. |
Geometric centere of a mirror is called _______ mirror.A. poleB. principle focusC. optic centreD. centre of curvature |
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Answer» Correct Answer - A Geometric of a mirror is called pole of the mirror. |
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| 175. |
The phenomenon of light which is responsible for vision is ______.A. refrationB. irregular reflectionC. dispersionD. Both (b) and (c) |
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Answer» Correct Answer - B The phenomenon which is responsible for vision is irregular reflection. |
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| 176. |
An incident ray passes through the centre of curvature of a concave mirror. After reflection the ray _______.A. passes through the principal focusB. retraces its pathC. passes along the principal focusD. None of these |
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Answer» Correct Answer - B An inicdsent ray passing through the centre of curvature retraces its path. |
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| 177. |
All the distances in case of spherical mirror are measured in relation to (a) object to image (b) the pole of the mirror (c) the focus of the mirror (d) the image to the object. |
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Answer» (b) the pole of the mirror |
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| 178. |
The radius of curvature and focal length of a concave mirror are (a) positive (b) negative (c) both (d) none of these |
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Answer» Correct answer is (b) negative |
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| 179. |
The radius of curvature of a mirror is 20 cm the focal length is (a) 20 cm (b) 10 cm (c) 40 cm (d) 5 cm |
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Answer» Correct answer is (b) 10 cm |
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| 180. |
Define pole, centre of curvature, radius of curvature, principal axis focus and focal length of a spherical mirror. |
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Answer» Pole: The centre of reflecting surface. It is represented by letter P. Centre of Curvature: The centre of the sphere of which the mirror forms the part. Represented by “C”. Radius of Curvature: The radius of the sphere of which the mirror forms the part. Represented by “R”. Principal axis: The straight line joining the pole (P) and the centre of curvature. It is normal to the mirror at its pole. Focus: The point of the principal axis at which the rays parallel to principal axis meet (concave mirror) or appear to meet (convex mirror) after reflection. Represented by F. Focal Length: The distance between the pole and the principal focus of a spherical mirror is called focal length. Represented by f. |
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| 181. |
What is he relation between radius of curvature and focal length of a spherical mirror? |
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Answer» f = R/2 where f is focus and R is radius of curvature |
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| 182. |
If the object is placed at focus of a concave mirror, the image is formed at (a) infinity (b) focus (c) centre of curvature (d) between F and O. |
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Answer» Correct answer is (a) infinity |
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| 183. |
The rear view mirrors used in vehicles are _____.A. planeB. concaveC. convexD. None of the above. |
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Answer» Correct Answer - C The mirror which is used as a rear viewer in vehicles is a convex mirror. |
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| 184. |
Match the following: `{:("Column A","Column B"),((A)"Laterally inverted image",(" ")(a)"Convex mirror"),((B)"Light rays emitted from a candle",(" ")(b)"Parallel beam of light rays"),((C)"Concave mirror",(" ")(c)"Convergent light rays"),((D)"Reflected light rays from a concave mirror"," when the object is at the centre of curvature of the mirror"),(,(" ")(e)"Inverted and real image"),(,(" ")(f)"Divergent light rays"):}`A. `Atoa,Btof,Ctoe,Dtoc`B. `Atod,Btoc,Ctoe,Dtof`C. `Atod,Btof,Ctoe,Dtoc`D. `Atod,Btof,Ctoa,Dtob` |
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Answer» Correct Answer - C A-d The nature of the image formed by a plane mirror is laterally inverted, virtual and of the same size as that of the object. B-f The light rays emitted from a candle are diverted light rays. C-e An inverted real image is formed only in a concave mirror. D-c The reflected light rays from a concave mirror, when the object is placed at the center of curvature, converge at the same point. These are convergent light rays. |
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| 185. |
The angle of deviation of a light ray reflected by a plane mirror is `150^(@)`. The angle of refection is _____.A. `30^(@)`B. `60^(@)`C. `15^(@)`D. `10^(@)` |
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Answer» Correct Answer - C The angle of deviation d =180-2i=180-2r 150=180-2r `2r=30^(@)r=15^(@)` |
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| 186. |
Choose the correct statement from the following.A. Light causes sensation of vision.B. The sensation of heat is due to the presence of infrared radiation.C. Light travels in a straight line.D. All the above. |
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Answer» Correct Answer - D (1) Light causes sensation of vision. (2) The sensatio of heat is due to the presence of infared radiation. (3) Light travels in a straight line. |
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| 187. |
What do you understand by candle power ? |
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Answer» Candle power — To measure the brightness of light in comparison with the brightness of a candle. The unit of candle power is used. |
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| 188. |
One foot candle= ______ lux.A. `12.56`B. `10.76`C. 700D. None of these |
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Answer» Correct Answer - B One foot candle =10.76 lux |
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| 189. |
The unit of power of lens is (a) metre (b) centimeter (c) dioptre (d) m-1 |
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Answer» Correct answer is (c) dioptre |
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| 190. |
The angle of incident of a light rays incidents on the surface of a plane mirror is `30^(@)`. The angle of deviation isA. `120^(@)`B. `30^(@)`C. `60^(@)`D. `90^(@)` |
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Answer» Correct Answer - A The angle of deviation `=180-2i=180-2xx30=120^(@)` |
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| 191. |
Fill in the blanks 1. The ............. and moon are the natural sources of light. 2. There are ........... and man-made sources of light. 3. The brightness of light is measured in ...................4. Shadows are formed when ............... blocks ..............5. Eclipses are the formation of .............. in nature. 6. A lunar eclipse is formed on ............ day. 7. A .............. is formed when the path of light is obstructed by an object 8. Light consists of ............. colours. 9. Pinhole camera is based on the ............. propagation of light.10. A solar eclipse occurs only on a ...................11. Speed of light in vacuum is ................ |
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Answer» 1. The Sun and moon are the natural sources of light. 2. There are natural and man-made sources of light. 3. The brightness of light is measured in .candle power 4. Shadows are formed when objects blocks light 5. Eclipses are the formation of shadows in nature. 6. A lunar eclipse is formed on full moon day. 7. A shadow is formed when the path of light is obstructed by an object 8. Light consists of seven colours. 9. Pinhole camera is based on the principle propagation of light. 10. A solar eclipse occurs only on a New Moons Day. 11. Speed of light in vacuum is 300000 km/sec |
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| 192. |
when the Moon comes into the umbra and penumbra of the Earth, _____ is formed. |
| Answer» Correct Answer - lunar eclipse | |
| 193. |
Which of the following is opaque?A. WaterB. GlassC. MirrorD. Prism |
| Answer» Correct Answer - C | |
| 194. |
When the Earth comes into the umbra and penumbra of the Moon, _____ is formed.A. lunar ecilpseB. solar eclipseC. partial lunar eclipseD. None of the above. |
| Answer» Correct Answer - B | |
| 195. |
Umbra is a region of 1. Partial darkness 2. Partial brightness 3. Complete brightness 4. Complete darkness |
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Answer» 4. Complete darkness |
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| 196. |
The size of image obtained by pinhole camera depends on ______ of camera. |
| Answer» Correct Answer - Size of the hole | |
| 197. |
Do you know how this light travel from the source? |
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Answer» Actually, light is not a single ray, but a bundle of rays- This bundle of light rays are called beam of light rays. . |
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| 198. |
Read the following statements and choose the correct option. (A) Onlly a point source forms a complete umbra. (B) An extended source forms a complete umbra and penumbra.A. Only A is trueB. Only B is trueC. Both A and B are trueD. Both A and B are false |
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Answer» Correct Answer - C Only a point source of light forms a complete dark patch on a screen, i.e., umbra. An extended source of light forms both umbra and penumbra. |
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| 199. |
An objcet is placed between two mirrors which make an angle of `45^(@)` with each other, then the number of images formed are _____.A. 8B. 7C. 2D. infinite |
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Answer» Correct Answer - B The number of image formed `(n)=(360)/(theta)-1` `=(360)/(45)-1` `=8-1=7` |
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| 200. |
An electric bulb converst _____ energy to ____ energy. |
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Answer» Correct Answer - electrical, light An electric bulb converts electrical energy to light energy. |
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