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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.
| 3101. |
While determining the focal length of a concave mirror, a student obtained the image of a distant object on a screen. In order to get the focal length of the mirror, the student should measure the distance : |
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Answer» between the OBJECT and the MIRROR only |
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| 3102. |
Electric energy is produced in various ways like hydroelectric, wind power, solar energy, bio-fuel, etc. These energy sources are inexhaustible, sustainable. Bisides, it does not cause any environmental problem. Draw the flow chart of production of electric energy? |
Answer» SOLUTION :
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| 3103. |
What is co-efficient of cubical expansion? |
| Answer» Solution :The ratio of increase in volume of the body per degree rise in temperature to its UNIT volume is CALLED as coefficient of CUBICAL EXPANSION. | |
| 3104. |
Electric energy is produced in various ways like hydroelectric, wind power, solar energy, bio-fuel, etc. These energy sources are inexhaustible, sustainable. Bisides, it does not cause any environmental problem. Above information is about which type of energy? |
| Answer» SOLUTION :From the above INFORMATION, we UNDERSTAND about GREEN ENERGY. | |
| 3105. |
Define coefficient of superficial expansion. Write its equation. |
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Answer» Solution :(i) The ratio of increase in area of BODY per DEGREE RISE in temperature to its unit area is called as coefficient of superficial EXPANSION . (ii) Coefficient of superficial expansion is DIFFERENT for different materials. (iii) The SI unit of Coeffficient of superficial expansion is `K^(-1)`. `(DeltaA)/(A_(0)) = alpha_(A)DeltaT implies alpha_(A) = (DeltaA)/(DeltaT.A_(0))` `DeltaA`- Change in area (Final area -initial area) `A_(0)`-Original area `DeltaT`-Change in temperature (Final temperature-Initial temperature) `alpha_(A)`- Coefficient of superficial expansion. |
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| 3107. |
A parrot is sitting on the floor of a wire cage which is being carried by a boy, starts flying. The boy will feel that the box is now |
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Answer» HEAVIER |
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| 3108. |
Process of transfer of heat through liquid and gases is .... |
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Answer» conduction |
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| 3109. |
List any two limitations in harnessing wind energ. |
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Answer» SOLUTION :(a) WIND-energy farms can be ESTABLISHED only at places where wind blows for the major part of the year (b) Establishment of wind farms REQUIRES a larga area of LAND. |
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| 3110. |
Choose the correct option. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each. |
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Answer» two REVOLUTIONS |
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| 3111. |
Explainthe various methods of producinginduced current. |
| Answer» SOLUTION :SEE NCERT QuestionNumber1 (page236 of TEXTBOOK). | |
| 3112. |
a) List the physical properties of metals. b) Differentiate between roasting and calcination. Explain the two with the help of suitable chemical equations. |
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Answer» Solution :Physical properties of metals are : i) Metals are usually hard. ii) They are Sonorous, iii) They are lustrus iv) Metals exhibit malleability and ductility v) They exhibit high tensil strength and have high densities: Roasting :It is a process in which sulphide ore is heated in the presence of oxygen to convert into OXIDE `2Zns-3O to 2ZnO + 2SO_2` Calcination : It is a process in which carbonate ore in heated in the ABSENCE of air of form oxides. `ZnCO_(3(s)) OVERSET("heat")to ZnO_((s)) + CO_2` By reduction process Zn can be EXTRACTED from its ore. Reduction: `2ZnO+ C to ZnO + CO_2` |
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| 3113. |
An ant is moving on a plane horizontal surface. The number of degrees of freedom of the ant will be |
| Answer» ANSWER :B | |
| 3114. |
Elders always instruct you to get out of the home to interact with relatives and others and play outdoor games but not to spend time continuously with television, phone and internet,Why the children of your age are instructed same in each home? |
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Answer» Solution :When we mix with the relative and interact with each other, it becomes easier to mix with other strangers later. The personality moulds when we talk and interact with different people.we can exchange the throught We learn to converse in a rightful way,When we go to playground and take PART in outdoor games,we get health benefits,Sitting at home and spending productive time in just mobile or computer games. does not benefit in any way. Most of the serials on the television are of no use for any kind of personality development,instead they PUSH us in a virtual world.Except for few channels like National Geographic and Animal Kindom ,We do not get any knowledge by television viewing . The elders in the house are experienced people.They UNDERSTAND What is good' and 'what is to be avoided' They also genuinely concerned about bright future of the youngsters in the house.By giving instructions to the youngsters,they NEVER get benefitted but it is our generation that gets proper guidance.These instructions should befollowed for aperfect personality and bright future. |
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| 3115. |
Geothermal energy is |
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Answer» fission of RADIOACTIVE MATERIALS |
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| 3116. |
If the temperatureof water is decreased from 4^(@)Cfrom 10^(@)C,then its "…..............." . |
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Answer» VOLUME DECREASES and DENSITY INCREASES |
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| 3117. |
What will you do? Why? You have to use free space around your home for good purpose. |
| Answer» Solution :I will create Artificial GRASS LAWN where my parents can do their MORNING walks and yoga, my sister/brother can play around and enjoy and I can relax when TIRED of STUDYING. | |
| 3119. |
Production of Yoghurt. |
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Answer» Solution :(1) Yoghurt is one of the milk PRODUCT produced from milk with the help of lactobacilli (inoculant). (2) In the industrial production of yoghurt, the milk is added with condensed milk powder. This increases the protein content of the milk. Then this milk is subjected to fermentation. (3) Milk is boiled and then it is cooled till it becomes lukewarm. (4) Then the bacterial strains of Streptococcus thermophilus and Lactobacillus delbrueckii are added to this lukewarm milk in 1:1 PROPORTION. (5) The Streptococcus bacteria CONVERT the milk into solution containing lactic ACID. This makes the PROTEINS to gel out. It makes the yoghurt dense. (6) The lactobacilli helps in the formation of acetaldehyde like compounds giving a characteristic taste to the yoghurt. (7) For commercial reasons, various fruit juices can also be mixed with yoghurt to impart different flavours forming Strawberry yoghurt, banana yoghurt, etc. (8) The pasteurization is carried out to increase the shelf life of yoghurt and improve its probiotic properties. |
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| 3120. |
An electron enters a magnetic field at right angles to it as shown in figure. What will be the direction of force acting on the electron ? State the rule which gives direction of force on electron. |
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Answer» Solution : Electron will move in a direction perpendicular to the plane of PAPER and into it. Flemings Left HAND Rule STRETCH the first three fingers of the left hand MUTUALLY perpendicular to each other such that the forefinger points the direction of magnetic field, the middle finger points the direction of current, then the thumb will indicate the direction of force experienced by the conductor. It is applied to the direction of the current and field perpendicular to each other. |
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| 3121. |
The act passed by Parliament of India for effective management of disaster. |
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Answer» |
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| 3122. |
Can you tell ? i. Which factor affect the environment?How ? |
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Answer» Solution :a. The factors affecting the environmentare natural and artificial factors. b. When natural or artificialfactors affect the environment ,they create an imbalance in the ecosystem and can affect the existence of biotic factors in the environment. C. Natural factors such as earthquakes,volcanoes, droughts,etc. can adversely affect the environment. d. ALSO, artificial or man-made factors like environment pollution caused due to population explosion, fast indusrialization ,and indiscriminate USE of natural resources, deforestation and unplanned urbanization can harm the environment. E. Biotic and abiotic factors are RELATED to each other in an ecosystem, and if any of the factors is changed or removed,it can affect the entire ecosystem and further affect the environment. |
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| 3123. |
Define the principal focus of convex mirror? |
| Answer» Solution :The principle FOCUS of a CONCAVE mirror ispoint on its principle axis to which all the LIGHT rays which is paralJel and CLOSE to the axis converge after REFLECTION from the concave mirror. | |
| 3124. |
To construct ray diagrams, two rays of light are generally so chosen that it is easy to determine their directions after reflection from a mirror. Choose two such rays and state the path/direction of these ray other reflection from a concave mirror. Use these two rays to find the postion and nature of the image of an object placed at a distance of 8 cm from concave mirror of focal length 12 cm. |
Answer» Solution : RAYS which are chosen to CONSTRUCT ray diagram for reflection are: (i) A ray parallel to the principal axis and (ii) A ray passing through the CENTRE of curvature of a concave mirro or appear to pass through the centre of curvature of convex mirror. Path of these rays after reflection: (i) After reflection, it will pass through the principal focus of a concave mirror or appear to diverge in case of a convex mirror. (ii) After reflection, it is reflected back ALONG the same path. `f=-12cm,u=-8cm` we know `1/f=1/v+1/u` `1/v=1/f-1/u=1/(-12)-1/((-8))` `=1/8-1/12` `=(3-2)/24` `=1/24=24cm` v=+ve so image is virtual and is formed at a DISTANCE of 24 cm behind the mirror. |
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| 3125. |
The time period of the satellite of the earth is 5 hr. If the separation between earth and satellite is increased to 3 times the previous value, then what will be the new time period of satellite. |
| Answer» SOLUTION :`(T_(2)^(2))/(T_(1)^(2))= ((R_2)/(R_1))^3 implies T_(2)^(2)= 27 xx25 implies 26hr`. | |
| 3126. |
What is the coefficient of performance (beta)of a carnot refrigerator working between 40^@and 0^@C? |
| Answer» SOLUTION :`beta=T_2/(T_1-T_2) =273/(313-273) = 6.8` | |
| 3127. |
Rocketworks on the principleof conservationof __________. |
| Answer» Answer :C | |
| 3128. |
Give scientific reasons for the following statements: We use AC for electric powertransmission over longdistance , while mostof the appliances use DC. |
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Answer» SOLUTION :Electric powertransmission over long DISTANCECAN result in a lotof loss of eletrical energyas the energy GETS dissipated as heat energy . The loss of powerin much less in the caseof AC relativeto DC. HENCE , we USE AC for electricpower trnasmissionover long distance . |
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| 3129. |
In an experiment to determine the focal length of a convex lens, a student obtained a sharp inverted image of a distant tree on the screen behind the lens. She then removed the screen and looked through the lens in the direction of the object. What will she observe? |
| Answer» SOLUTION :The SCREEN is just a DEVICE to observe the real image formed by a convex lens. The image of a DISTANT object CONTINUES to get formed at focus of the convex lens even when no screen is being used to show its formation. | |
| 3130. |
The specific latent heat of fusion of ice is 336 J/g. Comment on this. |
| Answer» SOLUTION :The heat required to convert 1 g of ice from `0^@C` to 1 g WATER at `0^@C` is 336 J | |
| 3131. |
Which social message would you like to give through it. |
| Answer» SOLUTION :(1) Instead of shooting the accident the victim should be GIVEN first aid.(2) Call on 100 and 108 and seek immediate help from police and ambulance. (3) DISPERSE the crowd and try to SAVE LIFE of victim by giving CPR . | |
| 3132. |
The critical angle for glass-air interface is : |
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Answer» `24^(@)` |
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| 3133. |
Select the eco-friendly activity among the following |
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Answer» Using car for transporation |
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| 3134. |
Experimentally prove that in series combination of three resistances: (a) Current flowing through each resistance is same , and (b) total potential difference is equal to the sum of potential differences across individual resistors. |
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Answer» Solution :Series combination of resistors: We take THREE resistors `R_1,R_2 and R_3` and JOIN them in series between the points X and Y in an electric circuit as shown in fig.12.51. (a) Plugthe key and note the ammeter reading. Then CHANGE the position of ammeter to anywhere in between the resistors and again note the ammeter readings. We find that ammeter reading remains unchanged. It shows that in series ARRANGEMENT same current flows through each resistor. (b) Insert a voltmeter across the ends X and Y of the series combination of resistors. Plug the key so as to complete the circuit and note the voltmeter reading V across the series combination of resistors. Take out plug from key K and disconnect the voltmeter. Now insert the voltmeter across the ends of first resistor `R_1` as shown in Fig.12.52. Plug the key and note the voltmeter reading `V_1`. Similarly, measure the potential difference across the other two resistors `R_2 and R_3` separately. Let these potential difference be `V_2 and V_3` respectively. Experimentally we find that `V=V_1+V_2+V_3` It shows that in series arrangement of resistors total potential difference is equal to the sum of potential differences across individual resistors. 
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| 3135. |
What is environmental pollution ? |
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Answer» Solution :UNNECESSARY and unacceptable changes in the environment due to NATURAL events or human activitiesis known as environmental pollution. OR Direct or indirect changes in physical , chemical and biological PROPERTIES of AIR, water and soil that are harmful to humans and other LIVING beings is called as environmental pollution. |
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| 3136. |
The image of candle flame placed at a distance of 40 cm from a spherical lens is formed on a screen placed on the other side of the lens at a distance of 40 cm from the lens. Identify the type of lens and write its focal length. What will be the nature of the image formed if the candle flame nature of the imge formed if the candle flame is shifted 25 cm towards the lens? Draw ray diagram to justify. |
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Answer» SOLUTION :Given Object DISTANCE `u=-40cm` Image distance `v=40 cm` Using lens formula `1/f=1/v-1/u=1//40-1//(-40)` or Focal length `f=+20 cm` The positive sign of focal length shows that it is a convex lens. Now Magnification `m=v//u=40//(-40)=-1` Thus the image is REAL, inverted and same size as object  If candel flame is shifted 25 cm towards the lens, then `u=-(40-25)=-15cm` then `1//20=1/v-1//(-15)=1/v+1//15` or v=-60 cm `m=v//u=-60//-15=4` Thus the image will be VIRTUAL, erect and enlarged. Refer to the following diagram 
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| 3137. |
TV programs, Mails, Mobile signal, News paper. |
| Answer» Solution :News PAPER. Other all are RELATED to ARTIFICIAL satellites . | |
| 3138. |
Complete a concept diagram to show use of biotechnology in human health : |
Answer» SOLUTION :
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| 3139. |
Explain various applications of Doppler effect. |
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Answer» Solution :To MEASURE the SPEED of an automobile An electromagnetic wave is emitted bya source attached to a police car. The wave is reflected by a moving vehicle, which acts as amoving source. There is a shift in the frequency of the reflected wave. From the frequency shift, the speed of the car can bedetermined. This helps to track the over speeding vehicles TRACKING a satellite The frequency of radio waves emitted by a satellite decreases as the emitted by a satellite decreases as the satellite passes away from the Earth By measuring the change in the frequency of the radio waves, the location of the SATELLITES is studied. RADAR (Radio Detection And Ranging) In RADAR, radio waves are sent,and the reflected waves are detected by the receiver of the RADAR station. From the frequency change, the speed and location of the aeroplanes and aircrafts are tracked. SONAR In SONAR, by measuring the change in the frequency between the sent signal and received signal, the speed of marine animals and SUBMARINES can be determined. |
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| 3140. |
State second law of thermodynamice . How is heat engine different from a refrigerator ? Explain. |
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Answer» Solution :Second Law of Thermodynamics : First law of thermodyamics is based on "Law of conservation of energy ". While second law of thermodynamics gives" information about the transformation of heat energy". So , there are two conventional statements of second law depending on common experience . 1) Kelvin - Plank statement : It is impossible foran engine working in a cyclic PROCESS to extract heat from a hot body and to convert it completely inot work . 2) CLAUSIUS Statement: It is impossible for a self acting machine , unaided by any external agency to transfer heat from a cold body to a hot RESERVOIR .In other words , heat cannot by itself flow from a colder body to a hotter body . Heat engine : A heat engine is a device used to convert heat energy into mechanical work . Generally heat engines will work in a cyclic process . Heat engine consists of three important units . 1) Source : which is an object or SYSTEM at high temperature . A heat enginewill absorb heat energy`Q_(1)`from source . 2) Working substance : Every heat engine requires a working substance to do work . Generally the working substance is like steam or fuel vapour and air mixture etc . A part of heat energy of working substance is converted into mechanical work . 3) Sink : In evergy heat engine heat energy content of working substance is not converted into worktotally . So some energy`(Q_(2))` is wasted or rejected by the engine . This rejectedenergy`(Q_(2))` is delivered to some other body or system at low temperature . This body with low temperature is called sink . EFFICIENCY of heat engine , `eta=("Work done")/("Heat energy supplied")=(W)/(Q_(1))` (But `W=Q_(1)-Q_(2))` (or)`eta=(W)/(Q_(1))=(Q_(1)-Q_(2))/(Q_(1))rArreta=1-(Q_(2))/(Q_(1))` Where `Q_(1)` = heat energy supplied by source `Q_(2)` = heat energy delivered to sink Block diagram of heat engine is as shown .  Refrigerator : A refrigerator works in the reverse process of heat engine . It extracts heat energy`Q_(2)` from sink i.e , from low temperature body with the help pf external work and delivers heat energy`Q_(1)` to high temperature body called source . work done`W=Q_(1)-Q_(2)` . In refrigerators external work is done on working substance . A block diagram of refrigerator is as shown .  Difference between heat enginc and refrigerator : Refrigeraote extracts heat energy from sink i. e .,from low temperature body with the help of external work and delivers heat energy to high temperature body called source . A heat engine will absorb heat energy from source and reject heat energy to then sink . Heat engine will work in a reversible process but the refrigerator works in the reverse process of heat engine . |
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| 3141. |
A bulb is rated 40W,220V. Find the current drawn by it when it is connected to a 220V supply. Also find its resistance. (b) If the given bulb is replaced by a blub of rating 25W,220V will there be any change in the value of current and resistance? Justify your answer and determine the change. |
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Answer» Solution :(a) Here power of bulb P=40W and voltage V=220V `therefore` Current drawn by the bulb `I=P/V=40/220=2/11A` and resistance of the bulb `R=V/I=220/((2/11))=(220 TIMES 11)/2=1210 Omega` (b) On TAKING another bulb of power P.=25W and voltage V=220V there is a charge in the value of current and resistance because their VALUES depend on the power of the bulb. NEW current `I.-(P.)/V=25/220=5/44A` and new resistance `R.=V/(I.)=220/((5/44))=(220 times 44)/5=1936 Omega` |
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| 3142. |
Draw a neat diagram of the structure of chromosome and label the parts : (a) Centromere (b) p-arm |
Answer» SOLUTION :
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| 3143. |
Theincreasesin temperatureof wateraboveof wateraboveitsboilingpointin thepressurecookeris duetochangein ______ |
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Answer» PRESSURE |
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| 3144. |
Plot a graph which shows the dependence of current I on potential difference V across a resistor R . |
Answer» Solution :ACCORDING to Ohm’s law, the current through a conductor is directly proportional to the potential difference across its ends. THUS, the GRAPH between I and V is a straight line PASSING through the origin. 
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| 3145. |
Lemon or tamarind is used for cleaning copper vessels turned greenish. |
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Answer» SOLUTION :(1) Copper undergoes oxidation in air to form black copper oxide. Copper oxide reacts SLOWLY with carbon DIOXIDE in air and gains a green COAT. This green substance is copper carbonate. (2) Lemon and tamarind contain acid. The acid dissolves the green coating of basic copper carbonate present on the surface of a tarnished copper utensil and makes it shiny again. |
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| 3146. |
For finding the focal length of a concave mirror, where do we keep the object? What is the position of image formed? On which structure we get the image? What is the nature of the image formed? |
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Answer» Solution :A large sized object placed at a FAR off (Infinity) PLACE, seen from the window of the lab, is taken as object. The image is formed at F point of the MIRROR. This image is formed on the screen. The distance between the mirror and the screen is measured, which is equal to focal length of the mirror. The image fomed is real and inverted. |
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| 3147. |
Name the force required for circular motion. State its direction. |
| Answer» SOLUTION :CENTRIPETAL FORCE | |
| 3148. |
List out the energy conversion in nature and in day to day life. |
Answer» Solution :Discuss VARIOUS ways of ENERGY conversions in nature as well as in our day to day activities and make a separate list of situations for natural conversions of energy and energy conversions in day to day life and write them in the GIVEN tables. 
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| 3149. |
Assertion : A gear is a circular wheel with teeth around its rim. Reason : It helps to change the speed of rotation of a wheel by changing the force and helps to transmit power. |
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| 3150. |
(a) Draw a neat and labelled diagram of the experimental set up for observing the scattering of light in a colloidal solution of sulphur to show how the sky appears blue, and the sun appears red at sunrise and sunset. (b) Out of blue light and red light, which one is scattered more easily? (c) Which component of sunlight is scattered away when the sun appears red at sunrise or sunset ? (d) What causes the scattering of blue component of sunlight in the atmosphere ? |
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