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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.
| 5351. |
What is the principleof an electric motor ? |
| Answer» Solution :A CURRENT-carrying CONDUCTOR placed in a MAGNETIC field experiences a FORCE when the direction of the current is PERPENDICULAR to the magnetic field. | |
| 5352. |
............ discovered that when a compass needle deflects when kept nearer to an electric circuit in which current is flowing. |
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Answer» Hans CHRISTIAN Oersted |
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| 5353. |
Refractive index of a transparent medium, so that it is invisible in vacuum is |
| Answer» ANSWER :A | |
| 5354. |
Transitional phase, reconstruction phase, phase of emergency, disaster management |
| Answer» SOLUTION :DISASTER MANAGEMENT - OTHERS are ASPECTS of disaster . | |
| 5355. |
List five things you have done over the last one week to a) Conserve our natural resources b) Increase the pressure on our natural resources |
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Answer» Solution :Five things done to conserve natural RESOURCES are: • Used energy efficient ELECTRICAL appliances. • Used only as electricity as was required. • Kept the water tap closed while BRUSHING the teeth. • Convinced mother to cook the food in a solar cooker • Used public transport for school instead of parent.s car. B) Five things done to increase the pressure on natural resources: • Went to school on a bike instead of cycle • Forgot to switch off fan while going out Wasted food Used more paper than required for printing on computer. •wastage of water resource. |
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| 5356. |
Biological factors are responsible for causing disasters. |
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Answer» Solution :Biological disasters ARISE DUE to sudden increase in population of certain kinds of plants (weeds), animals or MICROBES. They can be further classified as: i. Plant related disasters a. Forest fires occur due to natural causessuch as lightning, etc., that set the trees on fire. Humans can also intentionally or unintentionally provide a source of fire to ignite the forest. b. Overgrowth of weeds like common grass, carrot grass and certain common weeds may cause biological disasters. ii. Animal-related disasters. Biiological disasters may result from living organisms that may spread infectious VIRUSES or bacteria, that cause diseases/epidemics like CHOLERA, malaria (spread by infected mosquito), plague (spread by infected rodents) and hepatitis. Disasters may also occur due to bites from poisonous animals or when there is uncontrolled breeding of insects that spread disease, etc. |
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| 5357. |
A body of mass 10 kg is moving with a velocity of 20 m s^(-1) . If the mass of the body is doubled and its velocity is halved, find : (i) the initial kinetic energy, and (ii) the final kinetic energy |
| Answer» SOLUTION :(i) 2000 J (II) 1000 J | |
| 5358. |
(a) Write the function of each of the following parts of human eye : cornea, iris, crystalline lens, ciliary muscles (b) Millions of people of the developing countries of the world are suffering from corneal blindness. These persons can be cured by replacing the defective cornea with the cornea of a donated eye. A charitable socity of your city has organised a compaign in your neighbourhood in order to create awareness about this fact. If you are asked to participate in this mission how would you contribute in this noble cause ? (i) State the objective of organising such compaigns. (ii) List two arguments which you would give to motivate the people to donate their eyes after death. (iii) List two values which are developed in the persons who actively participate and contribute in such programmes. |
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Answer» Solution :(a) Functions of the following parts of human eye : (i) CORNEA. The front part of the eye is called cornea. It is made up of a transparent substance . The light coming from subject enters the eye through cornea. (ii) Iris. This is a flat, coloured , ring-shaped MEMBRANE behind the cornea. Pupil is a hole in the middle of the iris . Iris controls the size of the pupil. (iii) Crystalline lens.Eye lens is a convex lens which focuses the image of the object on the retina. (iv) Ciliary muscles. Ciliary muscles hold the eye lens and changes thethickness of eye-lens while focussing . (b) (i) Objective of such campaigns. To make people aware of corneal blindness and make them realise their duties TOWARDS the society by takingpledge for eye donation. (ii) `*` ONE pair of eyes can give eyesight to two corneal blind persons (each getting one eye), and make them see this beautiful world. `*` Our eyes can live even after our death. People belonging to all age groups , even people with medical conditions like CATARACT, diabetes , hypertension can donate their eyes. (iii) Values developed in persons who actively participate in such programmes: `*` Concern for others and social welfare `*` Responsible behaviour and awareness. |
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| 5359. |
The resistance of a thin wire is more than that of a thick wire of same length and same material. |
| Answer» Solution :TRUE- Resistance of a conductor is inversely PROPORTIONAL to its area of CROSS section. For a THIN wire the cross section area is SMALL and so its resistance is more. | |
| 5360. |
A copper wire has diameter 0.5 mm and resistivity of 1.6 xx 10^(-6) Omega m. What will be the length of this wire to make its resistance 10Omega? How much does the resistance change if the diameter is doubled? |
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Answer» Solution :We are given, the DIAMETER of the wire `d =0.5 mm =0.5 xx 10^(-3)m = 5 xx 10^(-4) m` Resistivity of copper `rho =1.6 xx 10^(-8) OMEGA m` Required RESISTANCE R = `10 Omega` Length l =? `AsR = (rho l)/A`, `l = (RA)/rho` `=(R(pir^2))/rho ( :. A = pi r^2)` `= (R (pid^2))/rho ( :. r = d/2)` =`(pi R d^2)/(4rho)` `=(3.14 xx 10 xx (5 xx 10^(-4))^2)/(4 xx 1.6 xx 10^(-8))` `= (31.4 xx 25 xx 10^(-8))/(6.4 xx 10^(-8)) = 785/6.4 = 122.7 m` Since resistance `R = (rho l)/A` `= (rho l)/(pi r^2) =(rho l)/(pi(d/2)^2) =(4rho l)/(pid^2)` `R prop 1/d^2` (If thereis no change in `rho and l`.) So. when diameter d is doubled. then resistance R BECOMES one-fourth of its original value. |
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| 5361. |
Which is having more resistance -a 220 V, 100 W bulb or a 220 V, 60 W bulb. |
| Answer» SOLUTION :60 W bulb because `R prop (1)/(P)` . | |
| 5363. |
The prism spit the incident white light into a band of colours. Write these colours name in sequence . |
| Answer» SOLUTION :Violet, Indigo, Blue, Green, YELLOW, Orange, and RED . | |
| 5364. |
Name the process by which nuclear energy is generated and aslo name one substance used for the same. Give two advantages and two hazards of nuclear energy. |
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Answer» Solution :Nuclear tission, Uranium, plutonium, thorium. Advantages : For a given amount of fuel, the amount of ENERGY released is extraordinarily large. Nuclear power plants can be set up at any PLACE. Hazards: Improper nuclear-waste storage and DISPOSAL result in environmental contamination. Further, there is a risk o ACCIDENTAL LEAKAGE of nuclear radlation. |
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| 5365. |
Read the folowing paragraph and answer the questions. If heat is exchanged between a hot and cold object, the temperature of the cold object goes on increasing due to gain of energy and the temperature of the hot object goes on decreasing due to loss of energy . The change in temperature continuous till the temperatures of both the objects attain the same value . In this process, the cold object gains heat energy and the hot object loss heat energy. If the system of both the objects is isolated from the environment by keeping it inside a heat resistant box (meaning that the energy exchange takes place between the two objects only), then no energy can flow from inside the box or come into the box Which property of the substance is measured using this principle? |
| Answer» Solution :The PROPERTY of SPECIFIC heat is MEASURED using this PRINCIPLE. | |
| 5366. |
State the important uses of wind energy . |
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Answer» SOLUTION :The wind energy is USED: (i) To generate ELECTRICITY (ii) To grind the wheat in flour MILLS. (iii) To run a pump to DRAW water form the ground. |
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| 5367. |
Read the folowing paragraph and answer the questions. If heat is exchanged between a hot and cold object, the temperature of the cold object goes on increasing due to gain of energy and the temperature of the hot object goes on decreasing due to loss of energy . The change in temperature continuous till the temperatures of both the objects attain the same value . In this process, the cold object gains heat energy and the hot object loss heat energy. If the system of both the objects is isolated from the environment by keeping it inside a heat resistant box (meaning that the energy exchange takes place between the two objects only), then no energy can flow from inside the box or come into the box How will you state the principle briefly? |
| Answer» Solution :Under ISOLATED conditions, the heat ENERGY lost by the hot BODY is equal to the heat gained by the cold body. | |
| 5368. |
Which changes occur in persons continuously using the internet and mobile phones? |
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Answer» Solution :When a person continuously remains in contact with mobile phones. Many physical problems can rise. (2) Tiredness,headache,insomnia,forgetfulness,tinntus,joint pains and problems in vision occur due to radiation emanating from the cell phones.For young children this is more disatrous as these radiations can penetrate through their bones. (3) by logging into the internet for a long time. persons become solitary.Such individuals are unable to establish HARMONIOUS relations withrelatives and other people around. (4) They tend to become self-centred and selfish They lose sensitivity towards others (5) Such people never take any social RESPONSIBILITY and the social HEALTH is thus disturbed. |
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| 5369. |
Read the folowing paragraph and answer the questions. If heat is exchanged between a hot and cold object, the temperature of the cold object goes on increasing due to gain of energy and the temperature of the hot object goes on decreasing due to loss of energy . The change in temperature continuous till the temperatures of both the objects attain the same value . In this process, the cold object gains heat energy and the hot object loss heat energy. If the system of both the objects is isolated from the environment by keeping it inside a heat resistant box (meaning that the energy exchange takes place between the two objects only), then no energy can flow from inside the box or come into the box Which principle do we learn about from this process? |
| Answer» SOLUTION :We LEARN the PRINCIPLE of HEAT EXCHANGE. | |
| 5370. |
Two coils P and S are wound over the same iron core. Coil P is connected to battery and key and the coil S is connected to galvanometer. Write your observations when: (i) Current in the coil P is started by closing the key. (ii) Current continues to flow in coil P. (iii) Current in coil P is stopped by removing the key. Explain the reason for such observation. |
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Answer» Solution : (i) There is DEFLECTION in galvanometer CONNECTED with coils, due to induced current. (ii) Deflection becomes zero. (ii)Deflection in galvanometer is in opposite direction. Reason: (i)E.M. INDUCTION TAKES place because field is changing (i) Since current becomes stationary, no change in field takes place. So no EM induction. (ii) E.M. induction takes place but induced current is in opposite direction. |
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| 5371. |
Read the folowing paragraph and answer the questions. If heat is exchanged between a hot and cold object, the temperature of the cold object goes on increasing due to gain of energy and the temperature of the hot object goes on decreasing due to loss of energy . The change in temperature continuous till the temperatures of both the objects attain the same value . In this process, the cold object gains heat energy and the hot object loss heat energy. If the system of both the objects is isolated from the environment by keeping it inside a heat resistant box (meaning that the energy exchange takes place between the two objects only), then no energy can flow from inside the box or come into the box Heat is transferred from where to where? |
| Answer» SOLUTION :HEAT is TRANSFERRED from hot BODY to COLD body. | |
| 5372. |
What will be the effect on electricaty generation if the channel taking water to turbine starts at points C in figure 5.17 ofyour textbook ? |
| Answer» Solution :As height decreases potential energy decreases. THUS at point C, potential energy of water will be MINIMUM. If a canal/penstock carrying water from dam starts at point C, this minimum potential energy will be converted into kinetic energy DUE to which turbines will ROTATE with less speed. Thus less electrical energywill be generated. | |
| 5373. |
What are hazards of electricity ? |
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Answer» Solution :Hazards of Electricity. Electricity is the most important SOURCE of energy. Whereas a PROPOER use of this is a BOON, improper use is very dangerous and may PROVE to be fatal. There are number of hazards. 1. If a PERSON touches a live wire, he gets a very severe shock. THis may prove fatal. 2. Loose connections, defective switches and sockets can cause sparking which may lead to fire. 3. Short-circuiting due to damaged wires or overloading of circuits can cause fires. |
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| 5374. |
Pre-disaster management and Post-disaster management. |
Answer» SOLUTION : 
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| 5375. |
If the Earth shrinksto 50% of its real rediusits mass remainingthe same , the weightof a body on the Earth will ___________ |
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Answer» DECREASE by 50% |
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| 5377. |
Match the following . {:("a) Angle of vision","i) 2.5 cm"),("b) Least distance of distinct vision ","ii) 25 cm"),("c) Maximum distance between eye lens and retina","iii) "60^(@)):} |
| Answer» SOLUTION :a-(III), B-(II), C-(i) | |
| 5378. |
On which factor the amount of charge accumulated on the plate depends in a battery ? |
| Answer» SOLUTION :NATURE of the CHEMICAL. | |
| 5379. |
Define impulse . |
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Answer» Solution :A large force acting for a very short interval of time is called as .Impulsive force.. When a force F acts on a body for a period of time t, then the product of force and time is known as .impulse. represented by .J. `"Impulse, J"=Fxxt"(1)"` By Newton.s SECOND law `F=Deltap//t""(Delta" refers of change")` `Deltap=Fxxt"(2)"` From (1) and (2) `J=Deltap` Impulse is also equal to the MAGNITUDE of change in momentum. Its unit is `"kg MS"^(-1)` or Ns. |
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| 5380. |
Find the value of λ so that the vector vecA=2hati+lambda hatj+hatk andvecB=4hati-2hatj+2hatk are perpendicular to each other. |
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Answer» SOLUTION :`because VECA BOT VECB RARR vecA. vecB =0because 8-2lambda+2=0` `rArr lambda=5`. |
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| 5381. |
When a convex lens is focussed on a distant object, where will the image be formed ? |
| Answer» SOLUTION :IMAGE is formed on the principal FOCUS of convex LENS on OPPOSITE side of lens. | |
| 5382. |
Why are the filament-type electric lightbulbs not power efficient? |
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Answer» Solution :When ELECTRIC power is supplied to the filament-type electric light bulb, most of the electric power consumed by the filament appears as heat (DUE to which the bulb BECOMES hot), only a SMALL amount of electric power is converted into light. So, the filament-type electric light bulbs arenot power efficient. [NOTE: Tube-lights are much more power efficient because they have no filaments.] |
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| 5383. |
How does the strength of the magnetic field at the centre of a current carrying circular coil depend on the (i) radim of the coil, (ii) number of turns in the coil, and (iii) strength of the current flowing in the coil ? |
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Answer» Solution :(i) INVERSELY PROPORTIONAL, more radius less strong magnetic FIELD. (ii) Oil.ectly proportional, more turns more strong magnetic field. (LII)DIRECTLY proportional, more strength of current more strong magnetic field. |
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| 5384. |
A coilis connected to a galvanometer. Whenthe N-poleof a magnet is pushed intothe coil, thegalvanometer deflected to the right. Whatdeflection, if any , isobservedwhen: (a) the N-poleis removed ? (b)the S-poleis inserted ? (c)themagnet is at rest in the coil ? State three waysofincreasingthe deflectionon the galvanometer. |
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Answer» (b) The galvanometer is deflected to the left (c) No DEFLECTION in galvanometer , Increase the number of turns in the coil , Use a stronger magnet , Increase the speed with Which magnet is pushed into the COID (or REMOVED) |
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| 5385. |
How much work is done in movinga charge of 2 C across two points having a potential difference 12 V ? |
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Answer» Solution :The amount of charge g, that flows between two POINTS at potential difference V (= 12V) is 2 C. Thus. the amount of work W, done in MOVINGTHE charge is `W = VQ` `=12 V XX 2C` `= 24J` |
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| 5386. |
The refractive indices of glass and water with respect to air are 3/2 and 4/3 respectively. If speed of light in glass is 2xx10^(8)m//s. Find the speed of light in water. |
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Answer» SOLUTION :Refractive index of a medium `=("Speed of LIGHT in air")/("Speed of light in the medium")` `3/2=("Speed of light in air")/(2xx10^(8)m//s)` Speed oflight in air `=3xx10^(8)m//s` Speed of light in WATER `=(3xx10^(8)m//s)/(4//3)=2.25xx10^(8)m//s=1` |
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| 5387. |
Production of cheese. |
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Answer» Solution :Cheese is made from cow's milk THROUGHOUT the world. The steps in the process of cheese MANUFACTURE are as follows : (1) Chemical and microbiological testing of milk is done. (2) Three types of bacteria, viz. Lactobacillus lactis, Lactobacillus cremoris and STREPTOCOCCUS thermophilus along wth some colour is added to the milk. (3) It imparts SOURNESS to the milk and it is converted into yoghurt like substance. (4) The water from this yoghurt, i.e. whey is not removed to make the yoghurt dense. (5) Enzyme, rennet or protease is added to the mixture to make it more dense. (6) Later cutting the solid yoghurt into pieces, rubbing, salting, and mixing of essential microbes, pigments and flavours is done in suitable steps. (7) The pressed cheese is then cut in to pieces and stored for ripening. |
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| 5388. |
List four properties of the image formed by a convex mirror. |
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Answer» Solution :PROPERTIES of image formed by a convex mirror : (1) It is always formed behind the mirror between the pole and its FOCUS. (2) It is always virtual and erect. (3) Its size is always SMALLER than the object. (4) Magnification is always positive. |
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| 5389. |
Draw the diagram of a mercury barmeter. |
Answer» SOLUTION :
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| 5390. |
What are different objects in the Solar system? |
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Answer» SOLUTION :1.Our solar SYSTEM CONSISTS of various PLANETS and their SATELLITES. 2. Besides these, there are asteroids, meteoroids, meteors and comets in the solar system. |
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| 5391. |
In a given ammeter, a student observes that the needle indicates 17 divisions in the ammeter when performing an experiment to verifY Ohm.s law. If the ammeter has 10 divisions between o and 0.5 A, then what is the value of 17 divisions? |
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Answer» Solution :Since the ammeter has 10 divisionsbetween 0 and 0.5 A, its least COUNT or value of 1 DIVISION `=(0.5A)/10 =0.05A` Therefore, the value of 17 DIVISIONS `=17(0.05A) =0.85A` |
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| 5392. |
A positively-charged particle [alpha particle] projected towards the west isdefiected towards the north by a magnetic field. The direction of the magnetic field is . |
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Answer» TOWARDS south |
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| 5393. |
(a) List the factors onwhich the resistanceof a conductorin the shape of the wire depend. (b) Why aremetals good conductors of electricity whereasglass is a bad conductorof electricity ? Give reason . (c ) Why are alloys commonly used in eletricalheating devices ? Give reason. |
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Answer» Solution :(a) Factorsonwhich theresistance of a conductor in the SHAPEOF a wire depends. (i) Theresistanceof a straightconductoris directlyproportionalto its length. `R prop l` (ii) The resistanceof a straightconductoris inversely proportionalto its area ofcross-section . `R prop l/A` From (i) and (ii) `R prop l/A` `:. R = rho'l/A`, ...[`rho` = constantcalledresistivity] (iii) the resistanceof a conductor also dependsuponthe temperature of the conductorand nature of materialused. (b)Metalshave free electronswhich helpsthem in the conductionof electricitywhereasglass hasno free electronsthereforeit is aninsulator. The resistivityof GLASSIS very HIGH `(=10^(10 ) "to" 10^(14) Omega m)` thereforeit is a poorconductorof electricitywhearesthe resistivity of metalsis lower,thereforemetalsare food conductors of electricity. (c ) Alloys arecommonly used in elctricalheatingdevices because - the resistivitiesof alloys are muchhigherthan those of the puremetals(fromwhich theyare made), an alloy does notundergo oxidation(or burn) easilyeven athigh temperature . Thusheatingelementsof electricalheatingappliances such aselectric iron,toaster, etc.are madeof an alloyrather thana pure metal . |
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| 5394. |
Describe an activity to show that the colours of white light splitted by a glass prism can be recombined to get white light by another identical glass-prism. Also draw ray diagram to show the recombination of the spectrum of white light. |
| Answer» Solution :Description of activity : When a glass prism is used to OBTAIN a spectrum of sunlight, a second identical prism in an inverted position with respect to the first position will allow all the colours of spectrum to recombine. Thus a BEAM of WHITE LIGHT will EMERGE from the other side of the second prism. | |
| 5395. |
What is meant by dispersion of light ? |
| Answer» Solution :When a beam of white light or COMPOSITE media such as glass or water, it is SPLIT into its componenet COLOURS. This PHENOMENON is called as 'dispersion of light' | |
| 5396. |
Khadins, Bundhis, Ahara and Kattas are ancient structures that are examples for |
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Answer» grains storage |
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| 5397. |
Match it. {:("1)Positively charged plate",(a)"anode"),("2)Negatively charged plate","(b)"cathode"):} |
| Answer» SOLUTION :1 - a, 2 - B | |
| 5398. |
Rotating effect of a couple is known as ………………………… |
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Answer» product of forces |
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| 5399. |
Explain : .Electrical resistivity is a characteristic property of the material.. |
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Answer» Solution :Metals and alloys have very low resistivity in the range of `10^(-8)Omegam" to "10^(-1)Omega m`. A good conductor of electricity has low resistivity and a poor conductor of electricity has a high resistivity. Insulators like rubber and glass have resistivity of the order of `10^12 Omegam " to " 10^(17) Omegam`. Copper and aluminium have very low resistivity (of the order of `10^(-8)Omega m`) due to which they are very good conductors of electricity. [And hence they are GENERALLY USED for electrical transmission lines.] Resistivity of alloys (e.g.. Nichrome, constantan) is higher (of the order of `10^(-6)Omegam`) than those of PURE metals from which they are made. [For this reason, they are commonly used in electrical heating devices like electric iron, toasters, etc.] The resistivity of SEMICONDUCTORS like SILICON (SI) and germanium (Ge) is between those of conductors and insulators and decreases on increasing the temperature. [And hence they are used for making (PN junction) diodes and transistors.] |
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| 5400. |
If the earth stop moving around its polar axis, then what will be the effect on the weight of a body placed at the south pole? |
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Answer» REMAINS same |
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