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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.
| 2201. |
Complete the process of iron rusting by filling the blanks. Suggest a way to prohibit the process.The rion rust is formed due to ______ reaction. Different regions on iron surface become anode and cathde. Reactionon anode region : Fe_((s)) to Fe_((aq))^(2+) + 2e^(-) Reaction on cathode region. O_(2(g))+ 4H^(+)_((aq)) + ________to2H_(2)O_((l)) WhenFe^(2+) ions migrate from anode region they react with _______ to formFe^(3+) ions. A reddiush coloured hydrated oxide is formed from ______ ions. It is called rust. 2Fe^(3+)_((aq)) + 4H_(2)O((l)) to _______ + 6H^(+)_((aq)) A way to prevent rusting ______ |
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Answer» Solution :The iron rust is formed due to `underline ("electrochemical") ` REACTION. different regions on iron SURFACE BECOME anode and cathode. Rection on anode region : ` Fe_((s))to Fe^(2+)_(aq) + 2e^(-)` Reaction on cathode region : ` O_(2(g)) + 4H^(+)_((aq)) +4e^(-) to 2H_(2)O_(l)` When ` Fe^(2+)`ionsmigrate from anode region they react with `underline ("water")` to form ` Fe^(3+)`ions. A reddish coloured hydrated oxide is formed from ` Fe^(3+)` ions. It is calledrust. ` 2Fe^(3+)_(aq) + 4H_(2)O_(l) to+ Fe_(2)O_(3).H_(2)O_(s) + 6H^(+) (aq)` A way to preventrusting by colouring with acylicpaints, ZN plating galvanizing , anodizing, alloying, etc. |
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| 2202. |
State the principleof anelectricgenerator . |
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Answer» SOLUTION :The working of an electric generatoris based upon the principle of electromagneticinduction . Principle: An electric currentproduced in a CLOSED circuitor coil BYA changing MAGNETICFIELDIS called an induced current . Thisphenomenonis called electromagneticinduction. |
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| 2203. |
Study these tables related to blood sugar levels and answer the questions that follow :Table A (Blood glucose chart)Which one of the following diets would you recommended to the affected patient ? |
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Answer» High sugar and LOW FAT DIET. |
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| 2204. |
What is mirror formula ? Does this formula hold good for a plane mirror ? |
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Answer» Solution :Mirror formula is `1/f=2/r=1/v+1/U` where f is the FOCAL length, r, the radius of CURVATURE, u, the DISTANCE of object and v, the distance of image from pole of the mirror. Mirror formula holds GOOD for all types of mirrors i.e., for plane, convex or concave. |
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| 2205. |
Use the data in Table 3.1 to answer the following : (a) Which among iron and mercury is a better conductor ? (b) Which material is the best conductor ? |
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Answer» SOLUTION :(a) Resistivity of iron `= 10.0xx10^(-8)OMEGA` Resistivity of mercury `=94.0xx10^(-8)Omega` Resistivity of mercury is more than that of iron. This implies that iron is a better conductor than mercury. (b) It can observed form Table 12.2 that the resistivity of SILVER is the LOWEST among the listed materials. Hence,it is BEST conductor. |
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| 2206. |
Specific latent heat of vaporisation : J/kg :: Specific heat : ______ |
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Answer» Solution :J/kg `""^(@)C` SI UNIT of specific LATENT heat of VAPORISATION is J/kg. SIMILARLY, SI unit of specific heat is J/kg `0^(@) C`. |
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| 2207. |
A nuclear reactor has half the length of all its control rods inserted in graphite. What must be done so that the reactor produces more heat ? Explain your answer. |
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| 2208. |
List four characteristics of the image formed by plane mirrors. |
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Answer» Solution :Four CHARACTERISTICS of the image formed by plane mirror: (i) It is always VIRTUAL and erect. (II) Size of image is equal to that of the object. (iii) image is formed at the same distance behind the mirror as the object is in front of the mirror. br> (IV) Image is laterally inverted. |
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| 2209. |
__________ formsthe basis of modern periodic table . |
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Answer» ATOMIC number |
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| 2210. |
Name two safety measures commonly used in eletric circuits and appliances. |
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Answer» SOLUTION :(i) Elecric FUSE (ii) Earthing of metal BODIES of ELECTRICAL appliances |
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| 2211. |
Prove that the sound is produced from a vibrating source. |
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Answer» Solution :1) Attach a small piece of steel wire to one of the prongs of a tuning fork as shown in the figure. 2) Strike the tuning fork with a RUBBER hammer. 3) While it is vibrating, try to DRAW a straight LINE on a piece of smoked glass as quick as posiible with it. 4) KEEP the end of the wire in such a way just it touches the glass. 5) A line is formed in the form ofa wave. 6) Repeat the experiment when the tuning fork is not vibrating and observe the difference in the line. Observations : 1) We have produced vibrations in the tuning fork by striking it with a hammer. 2) Thus the vibrating tuning fork produces sound. 3) Thus the sound is produced by vibrating bodies. 
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| 2212. |
State a difference between the wires used in the element of an electric beater and in a fuse. |
| Answer» SOLUTION :The MELTING point of the wire used in HEATER ELEMENTS is high while a FUSE wire has low melting point. | |
| 2213. |
State and explain Fleming's right hand rule for the direction of induced current. |
| Answer» Solution :The DIRECTION of induced current in a straight conductor is GIVEN by Fleming.s right hand rule. It states that spread the thumb, forefinger and the middle finger of your right hand at right angle to one another in such a way that the forefinger POINTS in the direction of magnetic FIELD, thumb pointsin the direction of motion of conductor then the direction in which the middle finger points, GIVES the direction of induced current. | |
| 2214. |
Nowadays, safer vaccines are being produced. |
| Answer» Solution :(1) Before the advent of BIOTECHNOLOGY, the vaccines were made from inactive or dead pathogens of that disease. (2) Such vaccines used to produce some disease symptoms is somecases. (3) The antigen of the disease is researched upon and its genetic code is found out. (4) A similar antigen is made in thelaboratories which is used as avaccine. (5) Such vaccines are more thermostable and remain active for longer duration. THEREFORE, the vaccines are now safer. | |
| 2215. |
Name two combustible components of biogas. |
| Answer» Solution :Methane and hydrogen are two combustible COMPONENTS of BIOGAS. | |
| 2216. |
Choosethe correct option : Themagneticfield inside a longstrainght solenoid carrying current … |
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Answer» is zero. |
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| 2218. |
Figures 9.6 (a), (b), (c), and (d) respectively correspond to |
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Answer» the SHORT-sighted EYE, the correction of long-SIGHT, the long-sighted eye and the correction of short-sight |
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| 2219. |
It is established that an electric current through a metallic conductor produces a magnetic field around it. Is there is similar magnetic field produced around a thin beam of moving (i) alpha particles, (ii) neutrons? Justify your answer. |
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Answer» SOLUTION :(i) YES, Alpha particles being positively charged constitute a CURRENT in the direction of MOTION. (ii) No. The neutrons being electrically neutral constitute no current. |
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| 2220. |
Find țhe relation between the first pair and complete the second pair. Electric oven : Heating eftect. Mixie: _____ |
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| 2221. |
Define coefficient of linear expansion. Write its equation. |
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Answer» Solution :(i) The RATIO of increase in length of the length of the body per degree rise in temperature is called 'Coefficient of LINEAR expansion'. (ii) Its SI unit is per kelvin. `(DeltaL)/(L_(0)) = alpha_(L)DELTAT IMPLIES alpha_(L) = (DeltaL)/(DeltaT.L_(0))` `deltaL`-change in length `L_(0)`- ORIGINAL length `DeltaT`-Change in temperature `alpha_(L)`-coefficient of linear expansion. |
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| 2222. |
It is recommended to use air tight container for storing oil for long time. Give reason |
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Answer» Solution :If eidble oil is allowed to stand for a LONG time , it undergoes air oxidation, it becomes RANCID and its smell and taste CHANGES. Rancidity in the food stuff COOKED in oil or ghee is prevendted by using antioxidants. The process of oxidation reactionof food stuff can also be slowed down by stroring it in air TIGHT container. |
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| 2223. |
Sacred groves are found only in Western Ghats in India. |
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Answer» SOLUTION :FALSE. SACRED Groves are FOUND all over India. |
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| 2224. |
Iron filings were added to a solution of copper sulphate. After 10 minutes, it was observed that the blue colour of the solution changes and a layer gets deposited on iron filings. What is the colour of the solution and the layer gets deposited on iron fillings. What is the colour of the solution and the layer deposited? |
| Answer» SOLUTION :The solution of the colour is green and that of the COATING is reddish-brown. This is because iron being more reactive than Cu displaces Cu from `CuSO_(4)` and forms green COLOURED solution of `FeSO_(4)` and a reddish-brown layer of Cu get deposited. | |
| 2225. |
Which light influences the opening of stomata? |
| Answer» Solution :Opening of stamata is INFLUENCED more by blue light because OXYGEN CONCENTRATION is MAXIMUM in blue light. | |
| 2226. |
(a) State the new Cartesian sign convention for lenses. (b) Define magnfication produced by a lens. How is it related to the object and image distance ? |
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Answer» Solution :(a) As per new Cartesian SIGN convention for lenses : (i) All distances parallel to the principal axis are measured from the optical centre of the lens. (ii) Distances to the right of optical centre are taken positive and distances left to optical centre are taken negative. (iii) The heights measured above the principal axis are taken positive and those below the principal axis are taken negative. (B) The magnification PRODUCED by a lens is DEFINED as the RATIO of the height of image (h.) to the height of object (h). Magnification produced by a lens is related to distances u and v as : Magnification `(m) = (h.)/(h) = ("Distance of image from the lens (v)")/("Distance of object from the lens (u)")` Magnification of real, inverted image is negative. Magnification of virtual, erect image is positive. |
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| 2227. |
Biogas contains 70% methane. The calorific value of methane is 55 kJ/kg. If a family requires 10,000 kJ of energy per day, how much biogas is needed per day? |
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Answer» Solution :55 k of ENERGY is produced by I g of methane. I0,000 kJ of energy is produced by = 10,000/55 = 181.8g methane. Since biogas contalns 70% methane, amount of biogas REQUIRED PER day = 181.8 `XX `70/100 = 127.26 g . |
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| 2228. |
_________ is the phenomenon of splitting of white light into its constituent colours while passing through a triangular prism. |
| Answer» SOLUTION :DISPERSION of LIGHT | |
| 2229. |
What are environmental consequences of the increasing demand for energy ? What steps would you suggest to reduce energy consumption ? |
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Answer» Solution :The demand of energy is increasing day by day. Exploiting any source of energy may DISTURB the environment in ONE way or other. For example, getting energy from fossil fuel may cause lot of pollution in air. Getting energy by nuclear fission may create problem of disposal of nuclear waste. Steps for reducing energy consumption should be such that we get maximum energy fromt least fuel. For this : 1. Under the given situation technology utilised should be the best possible. For example using smokeless CHULLAHS should be preferred to traditional chullahs. 2. Energy should be extracted by most economic method under the given situation.Whereas energy extraction by solar cell may be useless in big towns due to cost factor, it may be indispensable for artificial SATELLITES. 3. Wastage of energy should be STRICTLY avoided. Energy saved is equal to energy produced. 4. Sources of energy should be such that it causes the least damage to environment. |
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| 2230. |
g is vector and its direction is towards the centre of the |
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Answer» body |
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| 2231. |
Derive the expression for power P consumed by a device having resistance R and potential difference V. A derive of resistance R is connected across a source of V voltage and draws a current I. Derive an expression for power in terms for voltage for current and resistance. |
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Answer» SOLUTION :Amount of work done in carrying a charge Q through a POTENTIAL difference V is W=QV But `Q=It therefore W=Vit` As power is DEFINED as the rate of doing work, hence Power `P=W/t=(Vit)/t=VI` IF R be the value of resistance of the conductor , then V=RI and hence `P=VI=(RI)=I^2R` Again `P=VI=V.(V/R)=V^2/R` Thus, in general we can say that electric power is given by `P=VI=I^2R=V^2/R` |
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| 2232. |
How does locomotion take place in leech? |
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Answer» Solution :(a) Looping or crawling movement : Crawling movement is BROUGHT about by the CONTRACTION and relaxation of muscles . The two sukers serve for attachment during movement. (b)Swimming movement : Leeches swim very actively and perform undulating movement in water. (ii) Fossilization in plants : The process of formation of fossil in the rocks is called fossilization. 1. Petrifaction : Minerals like silica slowly penetrate in and replace the ORIGINAL organic tissue . This method can preserve hard and soft parts (e.g.) wood fossils . 2. Mold and Cast : A replica of a plant or animal is preserved in sedimentary rocks . when the organism get buried in sediment it is dissolved by underground water leaving a hollow depressin called Mold. It shows only the original shape and not the internal structure. Minerals or sediments fill the hollow depression and forms a cast . 3. Preservation : The entire plant may be preserved to protect from the orginism for decay . Ice or amber (tree sap) can be used for preservation. 4. Compression : When the organism dies , the hard parts settle at the bottom of the sea bed and are covered by sediment . The process goes on continuously and the fossils are formed. 5. Infiltration : The precipitation of minerals takes place which LATER on infiltrate the cell wall. The process is brought about by several mineral element such as silica, calcium carbonate and magnesium carbonate. |
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| 2233. |
We cn cut the DNA with the help of |
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Answer» RESTRICTION endonucleases |
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| 2234. |
How can you relate the formation of water droplets on the outer surface of a bottle taken out of refrigerator with formation of dew? |
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Answer» Solution :The amount of water vapour that a given volume of air can hold, depends on the temperature of the air. 2. Lower the temperature, lower is the capacity of air to hold water vapour. 3. When a BOTTLE is taken out of REFRIGERATOR, the temperature of air surrounding the bottle is decreased. 4. When air cools, due to decrease in temperature, it becomes saturated with water vapour. 5. As a result, the excess water vapour.gets CONDENSED into tiny droplets on the outer surface of the bottle. 6. The formation of dew is exactly like the formation of water droplets on the outer surface of a bottle taken out of a refrigerator. 7. Similarly a temperature falls at NIGHT, air becomes saturated with water vapour. 8. Excess water vapour gets condensed into tiny droplets and fall on the surface of leaves and grass as dew drops. |
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| 2235. |
The flow rate of water from a tap of diameter 1.25 cm is 0.48 L//mi n. The coefficient of viscosity of water is 10^(-3) Pa-s. After sometime, the flow rate is increased to 3L//mi n. Characterise the flow for both the flow rates. |
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| 2236. |
The heat produced in an electric heater of resistance 2Omega is connected to an electric source, when a current of 6A flows for 5 minutes . . .. . . . . . . . . . |
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Answer» `216xx10^(2)J` |
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| 2237. |
Name the physical quantity whose unit is volt/ ampere. |
| Answer» SOLUTION :RESISTANCE | |
| 2238. |
What are structure isomers ? Name the first member of alkanes that shows structural isomerism. |
| Answer» Solution :COMPOUNDS with IDENTICAL molecular formula but DIFFERENT structures are CALLED structural ISOMERS. | |
| 2239. |
. ............. is that temperature attained by two bodies when they are brought in thermal contact with each other are in thermal equilibrium, is attained |
| Answer» SOLUTION :EQUILIBRIUM TEMPERATUR | |
| 2240. |
A battery of 9 V is connected in serieswith resistors of 0.2 Omega, 0.3 Omega, 0.4 Omega, 0.5 Omega and 12 Omegarespectively. How much current would flow through the 12 Omega resistor? |
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Answer» Solution :Since all the given resistors are connected inseries, their equivalent RESISTANCE `R_s= 0.2 + 0.3 + 0.4 + 0.5 + 12 = 13.4 Omega` The CURRENT through the circuit, `I = V/R_s = 9/13.4 = 0.67 A` In a series combination, the same current I I flows through all the resistors, so the current flowing through `12OMEGA`s RESISTOR = 0.67 A. |
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| 2241. |
A thermally insulated pot has 150 g ice at temperature 0^@C. How much steam of 100^@C has to be mixed to it, so that water of temperature 50^@C will be obtained? Given:latent heat of melting of ice (L_f) = 80 cal/g , latent heat of vapourization of water (L_v)=540 cal/g , specific heat of water (C_w)=1 cal//g^@ C |
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Answer» Solution :The heat given of the stream `Q_S` will be equal to , `Q_S=m_S L_V + m_S c_W DeltaT` …(i) The heat taken in by the ice `Q_i` will be equal to , `Q_i=m_iL_f + m_ic_WDeltaT` ….(ii) Heat given off the stream `Q_s` is equal to heat taken in by the ice `Q_i`. So, `Q_s=Q_i` `m_SL_V+m_SC_W DeltaT = m_iL_f+m_ic_WDeltaT` [from (i) and (ii)] `(m_S xx 540 ) + (m_S xx 1 xx (100-50) = (150 xx 80) + {150 xx 1 xx (50-0)` `therefore m_S(540+50) = 12000 + 7500` `therefore 590 m_S = 19500` `therefore m_S=19500/590` `m_S`=33 G From the above observation we conclude that , 33 g of steam at `100^@` C MUST be MIXED with 150 g ice at `0^@C` |
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| 2242. |
UNEP : United Nations Environment Program :: WWF: "________________" |
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Answer» Solution :World WILDLIFE FUND The acronym of UNEP is United NATIONS Environment PROGRAM and that of WWF is World Wild life Fund. |
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| 2243. |
Define the term electric power and circuit its SI units. |
| Answer» Solution :The SI unit of ELECTRIC power is WATT. When a current of 1 ampere passes across the ends of a conductor, which is at a potential DIFFERENCE of 1 VOLT, then the lectric power is P = 1 volt `xx` 1 ampere = 1 watt | |
| 2244. |
(a) What is meant by(i) principal focus of a convex mirror, (ii) focal length of a convex mirror ? (b) Draw diagram to show the action of convex mirror on a beam of parallel light rays. Mark on this diagram principal axis, focus F, centre of curvature C, pole P and focal lenght f, of the convex mirror. |
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| 2246. |
Biogas is an excellent fuel. Justify the statement by giving two reasons. Mention the main constituents of biogas along with its percentage, |
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Answer» SOLUTION : i) It burns without smoke and LEAVE no residue therfore does not cause atmosperic pollution. ii) Its heating capacity is high i,e, it has high high calorific VALUE, main contituent of bio gas The composition of organic wastes varies depending upon the nature of organic matter feeding in the digester and advanced waste TREATMENT TECHNOLOGY The typical composition of bio gas is Methane50-75% Carbondioxide25-50% Nitrogen0-10% Hydrogen0-1% Hydrogen sulphide0-3% |
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| 2247. |
Near point : 25 cm :: far point : ____ |
| Answer» SOLUTION :infinity Near POINT of nonnal human EYE is 25 cm. Similarly, far point of nonnal human eye is infinity. | |
| 2248. |
Draw the labelled diagram of an A.C. generator. With the help of this diagram, explain the construction and working of an A.C. generator. |
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| 2249. |
Deflected by electric field : alpha ray, Null Deflection …... |
| Answer» SOLUTION :`GAMMA` RAY (Gamma ray) | |
| 2250. |
Explain qualitatively the working of a heat engine . |
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Answer» Solution :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 engine will 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 every heat engine heat energy content of working substance is not converted into work totally . So some energy`(Q_(2))` is wasted or rejected by the engine . This rejected energy`(Q_(2))` is delivered to some other body or system at low temperature . This body with low temperature is called 'sink". `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 . 
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