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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.
| 6251. |
As the ice is heated, it starts melting. Stir the mixture of ice and water. |
Answer» Solution : The GRAPH of temperature VERSUS TIME is SHOWN below. 
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| 6252. |
A ray of light travelling in air enters obliquely into water. Does the light ray bend towards the normal or away from the normal ? Why ? |
| Answer» Solution :The LIGHT bends towards the normal on ENTRY into WATER. It is due to the fact that as compared to air, the water in an optically DENSER medium. | |
| 6253. |
Assertion : If the refractive index of the medium is high(denser medium) the velcoity of the light. In that medium will be small. Reason : Refractive index of the medium is inversely proprotional to the velocity of the light. |
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Answer» If both assertion and reason are TRUE and reason is the CORRECT EXPLANATION of assertion. |
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| 6254. |
The conservation of electric charge implies that |
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Answer» charge cannot be CREATED. |
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| 6255. |
What is the SI unit of electric current? |
| Answer» SOLUTION :The UNIT of ELECTRIC CURRENT is AMPERE | |
| 6256. |
Na_(2) CO_(3). 10 H_(2) O is |
| Answer» Solution :Washing soda | |
| 6257. |
A ray of light falls normally on the surface of a transparent glass slab. Draw a ray diagram to show its path and also mark angle of incidence and angle of emergence. |
Answer» SOLUTION : `/_i=` Angle of INCIDENCE `=0^(@),/_e=` Angle of EMERGENCE `=0^(@)` |
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| 6258. |
Liquor is not produced from alcohol obtained through fermentation of substances. |
| Answer» SOLUTION :False-Liquor is PRODUCED from ALCOHOL OBTAINED through fermentation of substances | |
| 6259. |
fill in the blanks by suitable conversion of units : (i) 5ms^(-2) = ……. Km h^(-2) (ii) G = 6.67 xx 10^(-11) Nm^2 kg^(-2) =….. Cm^3 s^(-2) g^(-1) |
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Answer» SOLUTION :`G=6.67xx10^(-11)Nm^(2)kg^(-2)` `=6.67xx10^(-11)(KGMS^(-2))(m^(2)kg^(-2))` `=6.67xx10^(-11)kg^(-1)m^(3)s^(-2)` `=6.67xx10^(-11)(1000g)^(-1)(100CM)^(3)(s^(-2))` `=6.67xx10^(-11)xx(1)/(1000)xx100xx100xx100g^(-1)cm^(3)s^(-2)` `=6.67xx10^(-8)g^(-1)cm^(3)s^(-2)`. |
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| 6260. |
What is the relation between focal length and radius of curvature of a concave mirror? |
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Answer» `F=2 R` |
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| 6261. |
whenpressureis increaedat constanttemperaturethesolubilityof gases in liquid_______. |
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Answer» no CHANGE |
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| 6262. |
Specific latent heat of fusion and specific latent heat of vaporisation. |
Answer» SOLUTION :
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| 6263. |
The power of an electric device is a product of__________ and ___________. |
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Answer» |
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| 6264. |
What will you fo if, your borother studying in XII has developed stress ? Why ? |
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Answer» Solution :Increased stress can result I various adverse effects on physical,mental as well as cosical health of an invididual. If I find that my brother studying XII has developed stress, i. I will TALK with him and try understand WHETHER the stress is due to studies. ii. I will also help him in PREPARING timetable for his studies so that he GETS time for relaxation and some leisure along with studies. |
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| 6265. |
Sulphide ores : Froth floatation method : Cassiterite ore :________ |
| Answer» SOLUTION :MAGNETIC SEPARATION METHOD. | |
| 6266. |
Vinod went to his ancestral village alongwith his father during the summer holydays. He found that women of the village still used dried cow-dung cakes (uple) as the fuel to cook food and for other heating purposes. One day Vinod went to Panchayat meeting in the village which is attended by all the village elders and requested them to instal 'Gobar gas plant' in the village and use cow-dung in it to produce gobar gas, instead of burning cow-dung cakes directly. He explained the advantages of using gobar gas as a fuel instead of cow-dung cakes. Every one liked the idea and thanked Vinod for guidance. (a) State two disadvantages of using dried cow-dung cakes as a fuel for cooking food. (b) State two advantages of using gobar gas as a fuel for cooking food. (c) What values are displayed by Vinod in this whole episode ? |
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Answer» Solution :(a) (i) Burning of DRIED cow-dung cakes as fuel produces a lot of smoke which causes air pollution in the HOUSE and damages the health of all the family members, especially women and children. (ii) The burning of dried cow-dung cakes as fuel destroys the IMPORTANT plant nutrients (like nitrogen and phosphorus) present in them which could otherwise be used to increase the fertility of soil in the fields. (b) (i) Gobar gas burns without producing any smoke and hence does not cause any air pollution. This ensures good health for village people, especially women and children (who spend most of their time inside the house). (ii) The cow-dung slurry LEFT behind after the extraction of gobar gass still contains the plant nutrients (like nitrogen and phosphorus) which can be used as a manure in fields to increase the fertility of soil. (c) The values displayed by VINOD are (i) General awareness (or knowledge) of the alternative sources of energy (such as gobar gas), and (ii) Concern about the environment and health of village people (exemplified by his desire to reduce air pollution). |
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| 6267. |
The mean length of an object is 5 cm. Which of the following measurements is most accurate? |
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Answer» `4.9 CM` |
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| 6268. |
List any four methods that can be adopted by human-beings for contraception.Explain in brief how the health and prosperity of a familyis affected, if these methods are adopted by the husband or the wife. |
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Answer» Solution :Four contraceptive METHODS-(i) Mechanical barriers, (ii) Contraceptive pills, (iii) LOOP or Copper-T, (iv) SURGICAL methods, etc. Effects-(i)Frequentor unwanted pregnancies are avoided, (ii) Helps in protecting health of WOMEN, (iii) Parents can give more CARE to their child/children. |
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| 6269. |
Under what ideal condition the efficiency of a Carnot engine be 100%. |
| Answer» SOLUTION :If the TEMPERATURE of SINK is ZERO KELVIN. | |
| 6270. |
Which of the following property of light wave changes when it travels from one medium to another. |
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Answer» Solution :(a) Wave LENGTH (b) SPEED of LIGHT (c ) Frequency |
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| 6271. |
In the alumino thermic process, the role of Al is _________ |
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Answer» OXIDIZING AGENT |
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| 6272. |
Distinguish between. a. Farsightendness and Nearsightedness. |
Answer» SOLUTION : 
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| 6274. |
On which criteria is system of classification given by Robert Whittaker based upon ? |
| Answer» Solution :The System of CLASSIFICATION GIVEN by Robert WHITTAKER is based on following criteria like body ORGANIZATION , body symmetry , body cavity , GERMINAL layers , segmentation , etc . | |
| 6275. |
(i) Establish the relation between torque and angular acceleration. Hence define moment of inertia. (ii) Can a body in translatory motion have angular momentum?Explain? (iii) Extablish the relation between angular moment and moment of inertia for a rigid body. (iv) Why is it more difficult to revolvea stone by tying it to a longer string than by tying it to a shorter string? (v) State the law of conservation of angular momentum and illustrate it with the example of planetary motion. (vi) A cat is able to land on its feet after a fall. Why? |
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Answer» Solution :(i) YES, a body in translatory MOTION shall have angular momentum unless fixed point about which angular momentum is TAKEN LIES on the line of motion of body `therefore |vecL| = rp sin theta` =0 only when `theta = 0^(@)` or `180^(@)` (iv) MI of stone I `=ML^(2)` (`l to` length of string) `tau = Ialpha` `alpha = tau/I = tau/(ml^(2))` If l is large `alpha` is very small. `therefore` more difficult to revolve. |
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| 6276. |
Vijay is 16 yr old and wears a spectacle having a power of -2D. Answer the following questions: State two reasons why this defect is caused? |
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Answer» SOLUTION :The CURVATURE of the cornea and the eye lens increases, so that the converging POWER of the lens REMAINS large. (II) The eyeball elongates so that the distance between the lens and the retina increases. |
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| 6277. |
Enlist atleast six phenomena observed in nature subsequent to the scattering of light. |
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Answer» SOLUTION :The various PHENOMENA observed in nature due to scattering of light are the following: (i) Sun appears red near the horizons (during SUNRISE and sunset) and white when seen overhead. (ii) Bluish colour of the sky. (iii) Visible path of light as it enters a dark room. (iv) Danger signals or stop signals are usually red. (v) Blueness of DISTANT mouintains. (vi) SUNLIGHT filtering through clouds. |
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| 6278. |
(i) Rohit claims to have obtained an image twice the size of the object with a concave lens. Is he correct? Give reason for your answer. (ii) Where should an object be placed in case of a convex lens to form an image of same size as of the object? Show with the help of ray diagram, the position and nature of image formed? (iii) With the help of ray diagram, illustrate the change in position, size and nature of image formed if convex lens in case of (ii) is replaced by a concave lens of same focal length. |
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Answer» SOLUTION :(i) ROHIT's claim is not CORRECT. This is because image formed by a concave lens is always smaller in size than the object. (II) To form an image of size as the object, the object has to be placed at a distance `=2f` fromthe lens. The course of rays is asshown in Fig.  (III) In (ii) above, when a convex lens is replaced by a concave lens of same focal length, image formed is smaller in size than the object as 
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| 6279. |
Mr. Firoze is a retired man who lives in a big house. He has recently replaced all the filament-type bulbs in his house by CFls. His wife and children have a habit of keeping the lights and fans on (even when there is no one in the room) but Mr. Firoze keeps on going to every room periodically to switch them off. A few days back Mr. Firoze had purchased a device which can cook rice and dal without using any usual fuel. He has also installed an equipment on the roof of his house to obtain hot water. Mr. Firoze uses bicycle for short distances like going to nearby market, instead of scooter or car. (a) What is CFL ? Why has Mr. Firoze replaced all the filament-type bulbs in his big house by CFLs ? (b) Why does Mr.Firoze keep switching off lights and fans when no one is in the rooms? (c) Name the device which Mr. Firoze has purchased to cook rice and dal without using any usual fuel ? (d) Name the equipment which Mr. Firoze has installed on the house-roof to obtain hot water ? (e) Why does Mr. Firoze use bicycle for going through short distances ? (f) What values are displayed by Mr. Firoze by all the above actions ? |
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Answer» SOLUTION :(a) CFL STANDS for Compact Fluorescent Lamp. Mr. Firoze has replaced all the filament- type bulbs by CFLs to SAVE electricity (or electrical energy) because CFLs CONSUME much LESS electricity as compared to the traditional filament-type bulbs. (b) Mr. Firoze keeps switching off lights and fans when no one is in the rooms to save electricity by preventing its wastage. (c) Solar cooker. (d) Solar water heater. (e) Mr. Firoze uses bicycle for short distances to save petrol (which is used in scooter or car). Cycling also keeps him physically fit. (f) The value displayed by Mr. Firoze by all his actions are (i) Conservation (or saving) of fossil fuels like coal and natural gas (which are used to produce electricity), LPG (which is used to cook food or heat water), petroleum (which gives petrol to run cars and scooters), and (ii) Concern for the environment to keep it pollution free (because burning of less fossil fuels produces less air pollution). |
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| 6280. |
Explain the following serntences. (i). Energy obtained from fossil fuels is not green energy. |
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Answer» Solution :(a) ENERGY sources which are unlimited and ENVIRONMENT friendly are called as green energy sources is called green energy. b. Buring of fossil fuels LIKE coal NATURAL gas leads to emission of harmful gases like carbon monoxide nitrogen dioxide causing air POLLUTION. c.The reserves of fossil fuels are limited which are going to get depleted in the future. d. Thus, as the generation of energy from fossil fuels is not environmental friendly and the energy obtained from fossil fuels is not green energy. |
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| 6281. |
Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes? |
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Answer» Solution :An electric generator converts mechanical energy into electrical energy. Alternating CURRENT generators or AC generators produce alternating current. PRINCIPLE : It works on the principle of electromagnetic induction. Whenever the magnetic flux througha coil changes, induced current is produced.  CONSTRUCTION: Alternating current generator consists of a rectangular coil ABCD called armature. The armature coil consists of large number of turns of insulated copper wire wound over a soft iron core. The coil is kept between the poles of a strong magnet. In the figure shown `R_(1)` and `R_(2)` are two slip rings connected to the two ends of the coil and convey the current produced to outside circuit. `B_(1) and B_(2)` are two carbon brushes remain in sliding contact with slip rings. Working: The coil of the generator is rotated with the help of an axel. When coil rotates, it cuts the magnetic lines of force (magnetic field) near the north (N) and south (S) poles of the magnet. By electromagnetic induction, a current is induced in the coil. The direction of this current is given by Fleming.s right hand rule. As this coil turns clockwise, arem AB MOVES up and arm CD goes down. The direction of current is from A to B in AB and C to D in CD. The induced current is taken out through slip rings and carbon brushes. After half this rotation, AB and CD interchange their position. Now CD moves upward and AB downward. The direction of induced current is form D to C in CD and B to A in AB, during this half rotation. The slip rings `R_(1) and R_(2)` also rotate along with the coil ABCD. Thus, their polarities keep changing after every half rotation. Thus, the current changes its direction twice in one complete revolution of the coil. Such a current which changes its polarity after fixed intervals is called alternating current. Function of Brushes : The brushes `B_(1) and B_(2)` remain fixed in their positions and maintain sliding contacts with the rotatable slip rings `R_(1) and R_(2)` respectively. It is through these brushes that the current induced in the armature coil is fed to the external circuit by means of line wires. |
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| 6282. |
The control rods used in the reactor of a nuclear power plant are made of : |
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Answer» steel |
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| 6283. |
Give Scientific reasons . In practice, the unit kWh is used for the measurement of electrical energy, rather than Joule. |
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Answer» Solution :The UNIT of electric. POWER is 1 W (Watt), which is a very small unit, hence 1000 W or 1 kWused for the MEASUREMENT of electric power rather than Joule . 2. If 1 kWpower isused for 1 hour it MEANS1 kW x 1 hr of electric energyis used. 3.`therefore` 1 kW = 1 kilowatt hour = 1000 W x 3600 s = 3.6 x `10^6`WS = 3.6 x `10^6` J |
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| 6284. |
Compare and contrast biomass and hydroelectricity as sourcesof energy . |
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Answer» Solution :(i) Biomass is a renewable SOURCE of energy only if we plant trees in a planned manner which not the CASE with hydroelectricity . (ii) The energy form bio - mass can be OBTAINED by using a chulha or a gobar gas plant whereas hydroelectricity requires CONSTRUCTION of DAMS on rivers. (iii) Biomass provides pollution - free energy only when converted into bio - gas whereas hydroelectricity is totally pollution - free. |
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| 6285. |
An ideal gas undergoes for different processes from the same initial state (figure). Four processes are adiabatic, isothermal,isobaric and isochoric. Out of 1, 2, 3 and 4 which one is adiabatic ? |
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Answer» 4 |
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| 6286. |
How much time the satellite will take to complete one revolution around the earth? |
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Answer» SOLUTION :Given : Heightof the satellite above the earth's surface = 35780 km Velocity of the satellite = 3.08 km/sec Solution: Suppose, the satellite takes T seconds to complete one REVOLUTION around the earth. The distance travelled during this one revolution is equal to the circumference of the circular orbit. If R is the radius of the orbit, the satellite will travel a distance `2pir`during one revolution. Thus, the time required for one complete revolution canbe obtained as follows: `v=sqrt("distance"/"time")="circumference"/"time"=(2pir)/T` `T=(2pir)/v=(2PI(R+h))/v` =`(2xx3.14(6400+35780))/3.08` =86003.38 sec. =23.89 hrs. = 23 hrs. 54 M. |
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| 6287. |
which instrument used to measure resistance ? |
| Answer» Solution :If a MOLECULE contains more than THREE ATOMS, then it is called POLYATOMIC molecule. | |
| 6288. |
Now-a-days bio-diesel is used in transportation vehicles as an alternate to diesel. Write two advantages of this measure. |
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Answer» SOLUTION :(i) Eco-friendly/reduces the environmental pollution (II) RENEWABLE SOURCE of energy. (iii) Reduces the CARBON dioxide content in the atmosphere. |
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| 6289. |
State two advantages and two disadvantages of geothermal energy. |
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Answer» Solution :Advantages: (i) The use of GEOTHERMAL energy does not cause any pollution. (ii) The use of geothermal energy is quite economical. Disadvantages: (i) It is not available EVERYWHERE. (ii) Deep drilling in the EARTH to OBTAIN geothermal energy is very difficult. |
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| 6290. |
As ester has molecular formula C_(4)H_(8)O_(2). Write its structuralformula. What happens when this ester is heated in the presence of aqueous sodium hydroxide solution? Write the chemical equation for the reaction and also state the chemical name of the products formed. |
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Answer» Solution :`*CH_(3)-overset (O)overset(||)C-O-CH_(2)CH_(3)` `*` It gives an alcohol and CARBOXYLIC ACID. `* CH_(3)CO O C_(2)H_(5) overset(NaOH)rarr C_(2)H_(5)OH + CH_(3)C O OH` `*` Ethanoland Ethanoic acid |
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| 6291. |
The potential difference between two conductor is 110 V. How much work in moving 5 C charge from one conductor to the other? |
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Answer» SOLUTION :Given, V=110V, Charge Q=5C `V=(W)/(q)` `W=Vxxq` `W=110xx5=550J` `therefore`Work DONE W=550 J |
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| 6292. |
What is a voltmeter? |
| Answer» Solution :A measuring instrument used to MEASURE potential difference between TWO points in an electric circuit. | |
| 6293. |
Real expansion: heated directly :: Apparent expansion:_________. |
| Answer» SOLUTION :HEATED INDIRECTLY | |
| 6294. |
Organisms with modified endogenous gene of a foreign gene are also known as_____. |
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Answer» TRANSGENIC organism |
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| 6295. |
The central point of the lens on the principal axis is its …………… |
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Answer» CENTRE of curvature |
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| 6296. |
In case of a real and inverted image the magnification of a mirror is |
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Answer» positive and large |
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| 6297. |
What is equilibrant ? |
| Answer» Solution :A SYSTEM can be brought to equilibrium by applying ANOTHER force , which is equal to the RESULTANTFORCE in MAGNITUDE , but oppositein DIRECTION . | |
| 6298. |
Name the physical quantities that have dimensional formula [ML^(-1)T^(-2)]. |
| Answer» SOLUTION : STRESS, PRESSURE, MODULUS of ELASTICITY. | |
| 6299. |
What conclusion can you draw about the acceleration of a body from the speed-time graph shown below ? |
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Answer» UNIFORM acceleration |
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| 6300. |
Prove that a rainbow is the combined effect of the refraction, dispersion, and total internal reflection. |
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Answer» SOLUTION :i. The rainbow appears in the sky after a rainfall. ii. Water DROPLETS present in the atmosphere act as SMALL prism. iii. When sunlight ENTERS these water droplets it gets refracted and dispersed. iv. This dispersed light gets totally reflected inside the DROPLET and again is refracted while coming out of the droplet. v. As a combined effect of all these phenomena, the seven coloured rainbow is observed. 
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