InterviewSolution
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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.
| 2801. |
Minimum wind velocity required for making a windmill function is |
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Answer» 15 m/s |
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| 2802. |
Name a mirror that ca give an erect and enlarged image of an object. |
| Answer» SOLUTION :CONCAVE MIRROR. | |
| 2803. |
Namethe deviceswhich a currentcarrying conductorand magnetic fieldare used . |
| Answer» Solution :A current- carryingconductorand magnetic FIELD are USED in an ELECTRICMOTOR, electric generator , LOUDSPEAKER , microphone and measuring instruments. | |
| 2804. |
Assertion : There is an apparent change in frequency whenever there is a relative motion between a source & listener. Reason : SONAR & RADAR works under the principle Doppler effect. |
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Answer» Both assertion and reason are TRUE and reason is CORRECT explanation of assertion. |
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| 2805. |
2H_(2)+O_(2) to 2H_(2)O :Combination reaction:: 2HgO to 2Hg + O_(2) : ________ |
| Answer» SOLUTION :DECOMPOSITION REACTION | |
| 2806. |
If a sound wave travels with a frequency of 1.25xx10^(4)Hz at 344ms^(-1), the wave length will be |
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Answer» 27.52m `V=nlamda` `lamda=(v)/(n)=(344)/(1.24xx10^(4))` `lamda=0.02752m` |
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| 2807. |
(a) Design and activity with the help of two nails, a very thin aluminium strip, a 12 V Battery and a key to illustrate how an electric fuse works. (b) Cable of a microwave oven has three wires inside it which have insulation of different colour black, green and red. Mention the significance of the three colours and the potential difference between red and black one. |
| Answer» Solution :(b) RED colour is for LIVE wire. Black colour for Neutral wire. Green colour for the EARTH wire. P.D. between Red and Black wire is 220 volts. | |
| 2809. |
Let us hold a concave mirror in our hand and direct its reflecting surface towards the sun. Direct the light reflected by the mirror on to a sheet of paper held close to the mirror. Move the sheet back and forth till we find a bright, sharp spot of light on the paper sheet. Hold on the mirror and the paper in the same position for some time. We observe that the paper at first begins to burn producing smoke and eventually it may even catch fire. This activity shows the converging action of concave mirror. The heat produced due to the concentration of sunlight ignites the paper. Name the point where you observe bright sharp spot on the paper. Define it. |
| Answer» Solution :SUNLIGHT is FOCUSSED at the PRINCIPAL FOCUS (F) of the concave MIRROR. | |
| 2810. |
What is the main use of satellites that revolve in low earth orbit? |
| Answer» Solution :SATELLITES which are used in SCIENTIFIC experiments and ATMOSPHERIC studies REVOLVES in low earth ORBITS. | |
| 2811. |
Let us hold a concave mirror in our hand and direct its reflecting surface towards the sun. Direct the light reflected by the mirror on to a sheet of paper held close to the mirror. Move the sheet back and forth till we find a bright, sharp spot of light on the paper sheet. Hold on the mirror and the paper in the same position for some time. We observe that the paper at first begins to burn producing smoke and eventually it may even catch fire. This activity shows the converging action of concave mirror. The heat produced due to the concentration of sunlight ignites the paper. On which physcial phenomena is action of a mirror based ? Define it. |
| Answer» Solution :A mirror WORKS on the principal of REFLECTION of light. Reflection of light is the phenomenon of bouncing back of a light beam FOLLOWING certain LAWS after striking on a polished surface. | |
| 2812. |
In Fleming's left-hand rule the thumb indicates the direction of |
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Answer» magnetic field applied. |
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| 2813. |
Explain ‘elastomers’ with example |
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Answer» |
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| 2814. |
Let us hold a concave mirror in our hand and direct its reflecting surface towards the sun. Direct the light reflected by the mirror on to a sheet of paper held close to the mirror. Move the sheet back and forth till we find a bright, sharp spot of light on the paper sheet. Hold on the mirror and the paper in the same position for some time. We observe that the paper at first begins to burn producing smoke and eventually it may even catch fire. This activity shows the converging action of concave mirror. The heat produced due to the concentration of sunlight ignites the paper. Draw a ray diagram to show converging action of a concave mirror. |
Answer» SOLUTION :RAY DIAGRAM is SHOWN here. 
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| 2815. |
Let us hold a concave mirror in our hand and direct its reflecting surface towards the sun. Direct the light reflected by the mirror on to a sheet of paper held close to the mirror. Move the sheet back and forth till we find a bright, sharp spot of light on the paper sheet. Hold on the mirror and the paper in the same position for some time. We observe that the paper at first begins to burn producing smoke and eventually it may even catch fire. This activity shows the converging action of concave mirror. The heat produced due to the concentration of sunlight ignites the paper. Can the same activity be performed by a convex mirror too ? Give reason of your answer. |
| Answer» SOLUTION :The activity cannot be PERFORMED by using a convex mirror because convex mirror diverges the incident light beam and forms a virtural IMAGE which cannot be obtained on the PAPER SHEET. | |
| 2816. |
A current-carrying conductor placed in a uniform magnetic field experiences maximum force when the conductor is placed parallel to the magnetic field. |
| Answer» SOLUTION :The CURRENT CARRYING conductor placed in a MAGNETIC field experiences zero force when placed parallel to the magnetic field and experiences maximum force when held perpendicular to the magnetic field. | |
| 2817. |
How to identify saturatedand unsaturatedcompounds ? |
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Answer» Solution :(a) Law: .For energy action, there is an equal and opposite REACTION. They always act on two different bodies `F_(B)=-F_(A)`. Examples: (i) When birds fly: Push the air downwards with their wings-Action Air push the bird upward-reaction. (II) When firing bullet: Gun recoils backward and the bullet is moving forward-Action Gun equals this forward action by moving backward-Reaction. (b) * TAKE the GIVEN sample solution in a test tube. * Add a few drops of bromine water * If the given compound is unsaturated, it will decolourises bromine water. * If the given compound is saturated it will not decolourise bromine water. |
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| 2818. |
The reddening of the sum at sunrise is due to : |
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Answer» ACCOMODATION |
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| 2819. |
Refer to the plot of temperature versus time, showing the changes in the state of ice on heating (not to scale). whichof the followingis correct? |
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Answer» The REGION AB represents steam and water in thermal EQUILIBRIUM |
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| 2820. |
Concave lens always forms real and inverted image. |
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Answer» |
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| 2821. |
What is co-efficient of apparent expansion ? |
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Answer» Solution :(i) The ratio of the apparent rise in the volume of the liquid PER DEGREE rise in temperature of its UNIT volume. (ii) The SI unit of coefficient of apparent expansion is `K^(-1)`. |
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| 2824. |
The power of a lens is +5 D. Find its focal length in metres. |
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Answer» <P> Solution :FOCAL length `f = (1)/(P) = + (1)/(5)m` = 0.2 m |
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| 2825. |
A cylindrical conductor of length l and uniform area of cross section A has resistance R. Another conductor of length 2l and resistance R of the same material has an area of cross section |
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Answer» `A/2` |
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| 2826. |
Are electrons consumed in an electric circuit? |
| Answer» Solution :No. Electrons are not consumed in an ELECTRIC circuit. We pay the Electricity Board or Electric Company to provide electric energy to MOVE electrons through all the electric gadgets LIKE an electric FAN, electric bulb, refrigerator, etc. INSTALLED in our homes. We pay for the electric energy that we use. | |
| 2827. |
Choose the correct alternaive and write the alphabet corresponding to the correct answer: In a double displacement reaction…….. |
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Answer» IONS reamin at rest |
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| 2828. |
The phenomena of light responsible for the working of the human eye is |
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Answer» reflection. |
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| 2829. |
A coilof insulated copper wireis connctedto a galvnometer . Whatwill happen if a barmagnet is (i) pushed intothe coil , (ii)withdraw from insidethe coil, (iii) heldstationaryinside the coil ? |
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Answer» Solution :(i) The galvanometer will show a momentarydeflection in onedirection. Itmeans a currentis INDUCED inthe coilin one direction due to the relativemotion between the coil ANDTHE MAGNET. (ii) THEGALVANOMETER will showa momentray deflection in the oppositedirection due totherelativemotionbetween the coil and the magnet. (III)There will be no deflectionin the galvanometer . Itmeans no currentisinducedin the coil , as there is no relative motion betweenthe coiland themagnet. |
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| 2830. |
A student fixes a sheet of white paper on a drawing board. He places a bar magnet in the centre of it. He sprinkles some iron filings uniformly around the bar magnet. Then he taps the board gently and observes that the iron filings arrange themselves in a particular pattern. (a) Why do iron filings arrange in a pattern? (b) What does the crowding of iron filings at the end of the magnet indicate ? (c) What does the lines, along which the iron filings align, represent? (d) Draw a neat diagram to show the magnetic field lines around a bar magnet. (e) Write any two properties of magnetic field lines. |
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Answer» Solution :(a) Iron filings arrange in a pattern because a magnetic FIELD exists around a magnet. (b) The crowding of iron filings at the end of the magnet indicates that the strength of magnetic field is MAXIMUM near the poles of magnet. (C) The lines represent the magnetic field lines. (d) See Fig. 13.3. (e) See Question Number 2 (Textbook Page Number 228) of NCERT Textbook. |
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| 2831. |
State the conclusions that can be drawn from the observation that a current carrying wue deflects a magnetic needle placed near it |
| Answer» SOLUTION :A MAGNETIC FIELD EXISTS AROUND it. | |
| 2832. |
Explain the following: (a) Why is the tungsten used almost exclusively for filament of electric lamps? (b) Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal? (c ) Why is the series arrangement not used for domestic circuits? (d) How does the resistances of a wire vary with its area of cross sections? (e ) Why are copper and aluminium wires usually employed for electricity transmission? |
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Answer» SOLUTION :(a) Tungsten us used for filament of electric lamps because its melting point is extremely high (`3380^@C)` (b) Condutors of electric heating devices are made of an alloy rather than a pure metal due to the following reasons: (i) Resistivity of an alloy is generally higher that of pure metals hence for a given resistance we needa CONDUCTOR of less length. (ii) At high temperature an alloy does not oxidise (burn) readily.Hence, heating element prepared from an alloy has longer life. (c ) Series arrangement is not used for domestic circuits due to the following reasons: (i) In series arrangement same current will flow through all the appliances, which is not required. (ii) Total resistance of domestic circuit will be SUM of the resistances of all appliances and hence current drawn by the circuit will be less. (iii) We cannot use independent on/off switches with individual appliances. (iv) All appliances are to be used simultaneously even if we do not need them. (d) Resistance (R) of a WIRE is inversely to its cross section (A). (e ) Copper and aluminium wires are usually employed for electricity transmission because these are extremely good conductors having a low value of resistivity. More over, these are ductile and can be drawn in the form of FINES wires. |
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| 2833. |
A student fixes a sheet of white paper on a drawing board. He places a bar magnet in the centre of it. He sprinkles some iron filings uniformly around the bar magnet. Then he taps the board gently. Now answer the following questions: (i) What does the student observe ? Draw a diagram to illustrate your answer. (ii) Why do the iron filings arrange in such a pattern ? (iii) What does the crowding of the iron filings at the ends of the magnet indicate ? |
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Answer» Solution :(i) The student observes the magnetic field DUE to the given bar magnet. The pattern of magnetic field is SHOWN here. (ii) There is a magnetic field around the given bar magnet. The iron filings experience force due to the magnetic field and a THUS align themselves along the magnetic field lines. (III) The CROWDING of the iron filings at the ends of the magnet indicate the position of two magnetic poles N and S of given bar magnet. 
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| 2834. |
Wetlands occupy : |
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Answer» 6% of WORD's land |
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| 2835. |
Choose the incorrect statement from the following : |
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Answer» OZONE is a molecule formed by THREE atoms of oxygens |
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| 2836. |
Cancer cells are more easily damaged by radiations than normal cells because they are |
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Answer» DIFFERENT in structure |
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| 2837. |
State Ohm's law . |
| Answer» Solution :According to Ohm.s LAW, at a constant temperature, the steady current .I. flowing through a CONDUCTOR is directly proportional to the potential DIFFERENCE .V. between the two ends of the conductor. V = IR | |
| 2839. |
How is the amount of urine produced in human regulated ? |
| Answer» SOLUTION :The amount of urine produced is regulated by REABSORPTION of water and some of the dissolved subtances into the blood through bloodcapillaries surrounded by the tabules of nephrons. The amount of urine produced DEPENDS UPON how much exess water is present in the body and how much of dissolved salts are to be excreted. | |
| 2840. |
A car was moved from A to B of distance 4800 m in 4 hrs. If its speed is 10 m/s, the ratio of distance and displacement between A to B is |
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Answer» `1:2` |
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| 2841. |
While traching the path of a ray of light passing through a rectangular glass slab a student tabulated his observations. If in his experiment for two readings he takes two values ofangle ians 40^(@) and 50^(@) . What should be the correct values of anglee and angler in each case ? |
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Answer» Solution :Case I: when ` ANGLE = 40^(@)"" anglei = anglee` then ` angle e = 40^(@) "" (SIN (i))/(sin( r)) = ` constant ` ANGLER lt 40^(@) or angler = 23^(@)` Case II. when` anglei = 50^(@)` ` angle e= 50^(@)` `anglerlt 50^(@) or angler= 30^(@)` |
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| 2842. |
What is puberty ? |
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Answer» Solution :(i) In humans, during adolescence many more LOGICAL and physiological changes occur in body of both MALE and FEMALE. The male and female GAMETES production begins in RESPECTIVE report the active organs i.e., testis and ovary during puberty. |
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| 2843. |
% Relative humidity ( for a given temperature) |
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| 2844. |
You might have heard the sentences like "this month we have consumed 100 units of current". What does 'unit' mean ? |
| Answer» Solution :Units (or) kilo WATT hour is the consumption of electric POWER in one hour by our electric APPLIANCE. | |
| 2845. |
According to sign convention, distances measured in the direction of incident light are …………… |
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Answer» |
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| 2846. |
Suggest one way of discriminating a wire carrying current from a wire carrying no current. |
| Answer» Solution :BRING a MAGNETIC needle NEAR the wire, a current carrying wire will PRODUCE a deflection in the needle WHEREAS a wire without a current will not. | |
| 2847. |
A man opens a nut by applying a force of 150 N by using a lever handle of length 0*4m. What should be the length of the handle if he wants to open it by applying a force of 60 N? |
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Answer» Solution :Given, when effort=150 N, effort arm=`0*4m`. when effort=60N, effort arm=? LOAD and load arm REMAINS the same in both CASES. `therefore 150xx0*4=60xx`effort arm or Effort arm (i.e., length of length) `=(150xx0*4)/(60)=1m`. |
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| 2848. |
Number of which consumers will decline and which will increase? |
| Answer» Solution : The food chain if altered, results in imbalance in the ecosystem. 'Paddy `to` Grasshoppers `to` Frog `to` Snake', this food chain is natural. When by any reason there is decline in the NUMBER of frogs, THUS SECONDARY CONSUMER will also decline. Due to this decline, snake which is at tertiary consumer level will also decline. The primary consumers i.e. grasshoppers will increase as there is now no check on their population. Due to increase in their population the paddy production will be reduced. Due to reduced number of snakes, rats and other RODENTS from neighbouring areas would also rise, which are also secondary consumers. | |
| 2849. |
Breakdown of glucose molecule : Glycolysis : : Formation of glucose from proteins : ….. |
| Answer» SOLUTION :GLUCONEOGENESIS | |
| 2850. |
What do you mean by Disaster Management? What are the phases of disaster management? |
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Answer» SOLUTION :i. Disaster management is either AVERTING disasters or making arrangement to face it or at least achieveing the abilities to faces it. ii. Disaster managementis DIVIDED into predisaster management and post -disaster management. |
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