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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.
| 3951. |
a) State Mendeleev's periodic law. b) Did Mendeleev have gaps in his perodic table? c) Any three limitations of Mendeleev's classification. d) Does electronic configurations of atoms change in a period with increase in atomic number? |
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Answer» Solution :a) Mendeleev.s periodic law states that "the physical and CHEMICAL properties of all elements are the periodic function of their atomic masses"". b) Gaps were left for undiscovered element in the Mendeleev.s periodic table. c).i) Position of hydrogen was not JUSTIFIED ii) Increasing order of atomic mass could not be maintained iii) Isotopes have similar chemical properties but different atomic masses, they cannot be GIVEN separate places. d) NUMBER of shells remain the same, number of valence electrons goes on increasing from left to right in a period till octet is complete. 
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| 3952. |
Show four different ways in which three resistors of .r. ohm, each may be connected in a circuit. In which case is the eqUivalent resistance of the combination: ( 1 )Maximum? ( 2 ) Minimum? |
Answer» Solution :  (1) CIRCUIT (a) has MAXIMUM resistance (2) Circuit (b) has MINIMUM resistance |
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| 3953. |
A pulley system has a velocity ratio 3. draw a diagram showing the point of applicationi and direction of load (L), effort (E) and tension (T). It lifts a load of 150 N by an effot of 60 N. calculate its mechanical advantage. Is the pulley system ideal ? Give reason. |
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| 3954. |
An object is placed in front of a convex mirror of radius of curvature 40cm at a distance of 10cm. Find the position nature and magnification of mirror. |
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Answer» SOLUTION :u=-10cm R=-40cm Then f=R/2=-20cm From the mirror formula 1/v=1/f-1/u -1/20+1/10=1/20 V=20cm so v is POSITIVE Hence a virtual and erect IMAGE will be FORMED on the other side of the object, i.e BEHIND the mirror. M=-v/u=-20/-10=2 Magnification of mirror is 2 |
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| 3955. |
Why are coils of electric toasters made of alloy rather than pure metal ? |
| Answer» Solution :RESISTIVITY of alloys is MUCH more than pure metals. Hence heating of alloy `[W = I^(2) RT]` is much more than pure metals. | |
| 3956. |
How has the tradicional use of wind energy been modified for our convenience? |
| Answer» Solution :The traditlonal USE of WIND ENERGY has been modified by improvement In technology to generate electriciny through wind-power GENERATORS. | |
| 3957. |
Sound waves in gas is. ………………… |
| Answer» SOLUTION :LONGITUDINAL | |
| 3958. |
Where does the position of centre of gravity lie for (1) A circular lamina (2) A triangular lamina |
| Answer» SOLUTION :(a) At the POINT of INTERSECTION of its MEDIANS, (B) At the centre of circular lamina. | |
| 3959. |
What is the minimum speed of wind to run a windmill to maintain the necessary speed of turbine in an electric generator? |
| Answer» SOLUTION :15 km/hr | |
| 3960. |
Assertion: Extreme temperature is necessary to execute nuclear fusion. Reason: Ina nuclear fusion, thenuclei of the reactants combine releasing high energy. |
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Answer» if both the assertion and the reason are TRUE and the reason is the correct EXPLANATION of the assertion |
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| 3961. |
Reactor Kamini is situated at _________ |
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Answer» Kalpakkam |
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| 3962. |
Five resistors are connected in a circuit as shown. Find the ammeter reading when circuit is closed. |
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Answer» SOLUTION :The resistance between the POINTS B and D is x `x= (3Omegaxx6 Omega)/(3 Omega+6Omega) = 2 Omega` Now the resistance of the whole combination is ` R= 0.5 Omega+x + 0.5 Omega` `= 0.5 Omega +2.0 Omega + 0.5 Omega` `:.` Ammeter READING `= (3V)/(3Omega)` = 1.0 AMPERE. |
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| 3963. |
(a) Differentiate between nuclear fission and nuclear fusion.(b) Which of the two, nuclear fission and nuclear fusion, is made use of : (i) for the production of electricity ?(ii) for making a hydrogen bomb ? (c ) Which produces more energy : nuclear fusion or nuclear fission ?(d) Calculate the energy released in joules when 5 g of a material is completely converted into energy during a nuclear reaction. (e) How much is this energy in MeV ? (Speed of light = 3 xx 10^(8) m//s) |
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| 3964. |
Assertion: Electric appliances with a metallic body have three wire connections. Reason: Three pin connections reduce heating of the connecting wires. |
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Answer» If both the assertion and reason are true and the reason is the correct explanation of the assertion. |
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| 3965. |
(i) An object is placed at a distance of 60 cm from a convex mirror where the magnitication produced is 1/2. Where should the object be placed to get a magnification of 1/3 ? (ii) A small electric lamp is placed at the focus of a convex lens. State the nature of beam of light produced by the lens. Draw a diagram to show this. |
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Answer» Solution :(i) `u=-60cm` `m=+1/2` `m=1/u=1/2` `1/1=(-v)/(-60)` `v=30cm` Using MIRROR formula `1/f=1/u+1/v=1/60` `f=60cm` Now `m=1/3:.1/u+1/v=1/fimplies1/(-u)+1/v=1/60` `u=-60cm` (ii) When a SMALL ELECTRIC lamp is placed at the focus of a convex LENS, a paralel beam of LIGHT is produced by the lens. Ray diagram. 
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| 3966. |
In an experiment on tracing the path of a ray of light through a rectangular glass slab, four students A, B, C and D used the following values of the angle of incidence and the distance between the feet of the two pins (fixed on the incident rays) : |
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Answer» `30^(@), 45^(@), 60^(@)` and 1 cm |
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| 3967. |
Piracy, hacking of information, sale of inferior quality items on websites, addition. |
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Answer» Solution :Addition All other are examples of CYBER crimes while addition is not a cyber CRIME. |
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| 3968. |
Government does not categorise any website, movies or cartoon films as being inppropriate for children. |
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Answer» SOLUTION :False. Government bans any webisite, mocide or CARTOON FILMS which it dems inappropriate for children. |
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| 3969. |
Distinguish between renewable and non renewable sources of energy. |
Answer» SOLUTION :
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| 3970. |
Define Hooke's law of elasticity and describe an experiment to determine the Young's modulus of the material of wire. |
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Answer» Solution :Hooke.s Law : Within elastic limit, stress is directly propportional to strain. `therefore"strain"prop"stress"` `("stress")/("strain")="CONSTANT"(E)` where E constant called modulus of elasticity of the material of a body. Determination of young.s modulus of a wire : The apparatus used to find young.s modulus of a wireconsists of two long wires A and B of same length made with same material are used. These two wires are sus- pended from a rigid support and a vernier scale .V. is attached to them. Wire A is con- nected to the main scale (M). A fixed load is connected to this cord to keep tension in the wire .This is called reference Wire. The second wire. .B. is connected to vernier scale .V.. Adjustable load hnger is connected to this wire. This is called experimental wire. Procedure : Let a load `M_(1)` is attached to the weight HANGER at vernier. Main scale reading (M.S. R) and vernier scale reading (V.S.R) are NOTED. Weights are gradually INCREASED in the steps of `(1)/(2)kg` upto a maxi- mum load of say 3 kg . Every time M.S.R and V.S.R are noted for every load, values are posted in tabular form. Let `1^(st)` reading with mass `M_(1)"is"e_(1)` and `2^(nd)"reading with mass"M_(2)"is"e_(2).` Change in load `M=M_(2)-M_(1)` `"elongation"e=e_(2)-e_(1)` .M. and .e. values are calculated and a garaph is plotted.  Average `m//e=` Force on the wire =mg Area of cross section of the wire `pir^(2)` `(r=radius of the wire)` Elongation = e Original length = l `"Stress=((F)/(a))=(mg)/(pir^(2))` `"Strain"=((e)/(l))` `"Young.s modulus,"Y=(("stress")/("strain"))` `thereforeY=((mg//l)/(epir^(2)))=((gl)/(pir^(2)))((m)/(e))`  A graph is between load (m) and elongation .e., is straight line passing through the origin. The SLOPE of the graph `(tantheta)` gives `((m)/(e))`. This value is substituted in the above eqution to find Young.s modulus of the material of the wire. Precations : 1. The load applied should be much smaller than elastic limit. 2. Reading is noted only after the air bubble is brought to centre of sporit level. |
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| 3972. |
Gamma rays are deflected by both electronic and magnetic fields. |
| Answer» Solution :GAMMA rays are not DEFLECTED by both electronic and magneitc FIELDS. | |
| 3973. |
What are the changes that will occur when heat energy is given to a substance ? |
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Answer» Solution :(i) Temperature of the substance RISES. (ii) The substance MAY change its state from solid to LIQUID to GAS. (iii) The substance will expand when HEATED. |
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| 3974. |
Assertion (A): In series grouping of resistances the equivalent resistance is greater than even the biggest resistance joined in series. Reason (R ): In series arrangement the equivalent resistance Rs is given as per the relation 1/R=1/R_1+1/R_2+1/R_3+...... |
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Answer» Both (A) and (R ) are TRUE and (R ) is correct EXPLANATION of the assertion |
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| 3976. |
Explain the formation of ionic compound CaO with electron-dot structure. Atomic numbers of calcium and oxygen are 20 and 8 respectively. |
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Answer» Solution :Calcium has the electron distribution : 2, 8, 8, 2 OXYGEN has the electron distribution : 2, 6 Thus CA has 2 electrons in the outermost shell. Ca has the tendency to donate 2 electrons and oxygen has the tendency to GAIN 2 electrons FORMING an ionic bond. This can be REPRESENTED as under : 
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| 3978. |
What is the exact difference between grades of organization and symmetry ? Explain with examples. |
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Answer» Solution :I. Grades of organization : (1) The grades of organization mean the way an organism has different bodyformation . (2) UNICELLULAR organisms like amoeba have a single cell in the body and hence the organization in its body is CALLED protoplasmic grade of organization . (3) Some organisms have onlycells in their body which is called cellular grade of organization . e.g. Poriferans. (4) Somehave tissues e.g. Coelenterates . They are said to have tissue grade organization . Some have organs , they are said to have organization - organ grade. e. g. Plathyheminthes . All other higher ANIMALS have organ - system grade organization . II. Symmetry : (1) Symmetry on the other hand shows the base of the body formation . (2) The symmetry can be understood by taking an imaginary cut through the animal body. (3) Based on the symmetry there can be three types. (4) In asymmetric animals, there is no symmetry in any plane . e.g. Amoeba. (5) The bilateral symmetry is the one in whichan imaginary axis can pass through only one median plane to divide the body into two equal halves. Most of the animals have bilateral symmetryand hence their organs are arranged in symmetric way on both the sides. (6) The imaginary cut passing through the CENTRAL axis but any plane of body can give more than one equal half. The organs of such animals are arranged in a radius of an imaginary circle.e.g. Cnidarians and some echinoderms. Both grades of organization and symmetry are the bases for classifying animals into different phyla. |
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| 3979. |
An ammeter has a range (0 - 3A) and there are 30 divisions on its scale. Calculate the least count of the ammeter. |
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Answer» Solution :Here, range of ammeter = 3 ampere (Le., The MAXIMUM CURRENT that can be MEASURED by the given ammeter is 3A.) No. of divisions on scale of ammeter = 30 The least count of the ammeter `= ("Range of the ammeter")/("Total no.of divisions")` `=(3A)/(30) = 0.1 A` (Le., MINIMUM current that can be accurately measured by a given ammeter is 0.1 A.) |
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| 3980. |
Several electric bulbs designed to he used on a 220 V electric supply line, are rated 10 W. How many lamps can be connected in parallel with each other across the two wires of 220V line of the maximum allowable current is 5A ? |
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Answer» Solution :Resistance of each BULB = R[say] `R=V^(2)/P=(220xx220)/10=4840Omega` Let n such BULBS be connected in parallel. Then `1/R_(p)=1/4840+1/4840+.....n" times"=n/4840` `R_(p)=4840/nOmega` `R_(p)=V/IrArrI=V/R_(p)` `5GE(220n)/4840` `nle110` Number of electric bulbs = 110. |
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| 3981. |
Uncontrolled chain reaction yields |
| Answer» Solution :atom bomb | |
| 3982. |
A linear object is placed at a distance equal to focal length of a convex mirrro. Its image is formed |
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Answer» at infinite distance As PER SIGN convention u = -f and focal length of convex mirror is +ve, HENCE from mirror formula `(1)/(v) + (1)/(u) = (1)/(f)`, we have `(1)/(v) + (1)/((-f)) = (1)/((+f)) or (1)/(v) = (1)/(f) + (1)/(f) = (2)/(f) or v = + (f)/(2)` |
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| 3983. |
.... ..... promotes the production of male flowers in Cucurbits. |
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Answer» Auxin |
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| 3984. |
In order to obtain a magnification of, -1.5 with a concave mirror of focal length 16 cm, the object willhave to be placed at a distance : |
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Answer» between 6 CM and 16 cm |
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| 3985. |
According to kinetic theory of gases at absolute zero |
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Answer» WATER freezes |
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| 3986. |
Distinguish between the kilowatt and the kilowatt hour. |
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Answer» Solution :The kilowatt (kW) 1S a UNIT of power and the kilowatt HOUR (kWh) is a unit of electric energy. `1 kWh =1 kW xx 1H` |
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| 3987. |
Find out the source of water in your region/locality . Is water from this source available to all people living in that area ? |
| Answer» Solution :The sources of WATER in my LOCALITY are groundwater through handpump and the municipality supply . SOMETIMES , especially in summer SEASON , water from THESESOURCES becomesscant . In my locality water is availlable to all the people. | |
| 3988. |
Out of the combinations of resistors mentioned above in the previous part, for a given voltage which combination will consume more power and why ? |
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Answer» <P> Solution :Since power `P=(V^(2))/(R )`, hence for a GIVEN VOLTAGE `P prop (1)/(R )` i.e., power is more if resistance is less.So it is clear that PARALLEL combination of conductor parts will consume more power. |
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| 3989. |
Whena stoneis droppedon thesurface of stillwater, wavesproducedare |
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Answer» TRANSVERSE |
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| 3990. |
Which are the effects of dry famine? |
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Answer» Solution :(i) Scarcity of WATER. (II) No agricultural production. (iii) No water for drinking. (iv) Scarcity of food and other useful commodities. (v) BIODIVERSITY will be in danger. |
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| 3991. |
How did Dobereiner classify the elements? Give one example of what were the limitations of this classification. |
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Answer» Solution :He classified in group of three such that atomic No. of middle elements is average of first and third element. Eg: Li(7), Na(23), K(39), LIMITATIONS : * Dobereiner could find only three TRIADS, i.e. total of 9 elements only. * However the total NUMBER of elements were more than that of those encompassed in Dobereiner.s triad. * THUS Dobereiner could not classify most of the elements known at that time.. |
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| 3992. |
What is meant by scattering of light ? Use this phenomenon to explain why the clear sky appears blue or why the sun appears reddish at sunrise. |
| Answer» Solution :SCATTERING is a PHENOMENON where a beam of light is absorbed and then re-emitted in different directions when it interacts with PARTICLES. Blue colour is scattered the most and red colour the least by air molecules and particles in the earth.s atmosphere. At distance or sunst, sunlight will have to PASS through longer distance in the atmosphere. Then, blue colour [shorter wavelength] would have been mostly removed by scattering leaving behind red colour [longer wavelengths] which reaches our eyes. Thus, at sunset or SUNRISE, the sun appears orange in colour. | |
| 3993. |
How does a solenoid behave like a magnet? Can you determine the north and south poles of a current solenoid with the help of a bar magnet ? Explain. |
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Answer» Solution :Current carrying solenoid behaves as a magnet. The end in which the current is ANTI CLOCKWISE ACTS as north pole and other end in which current is clockwise acts as south pole. Suspend a current carrying solenoid. Bring north pole of the bar magnet towards one end of the solenoid. If the solenoid is attracted towards its north pole then this ernd ot solenoid is south pole and vice-versa. |
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| 3994. |
The band of coloured components of a light beam is called its …………… . |
| Answer» SOLUTION :SPECTRUM | |
| 3995. |
The resistivity of a material is 4xx10^(-8)Omega m and its conductivity. . . . . . . . |
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Answer» `25xx10^(-8)"MHO m"^(-1)` |
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| 3996. |
While catching a cricket ball the fielder lowers his hands backwards. Why? |
| Answer» SOLUTION :While catching a cricket ball the fielder lowers his hands backwards. So INCREASE the time during which the VELOCITY of the cricket ball DECREASES to zero. Therefore the impact of force on the palm of the fielders will be reduced. | |
| 3997. |
Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side. What is the direction of magnetic field? |
| Answer» SOLUTION :VERTICALLY DOWNWARDS | |
| 3998. |
State whether the following statements are true or false : |
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Answer» An electric motor converts mechanical ENERGY into electrical energy. |
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| 3999. |
Define the term-biomass. Name any two biomass energy sources. |
| Answer» Solution :The materials obtained from PLANTS and animals, used as FUELS are called biomass. Coal, wood ETC., are the SOURCES of biomass energy. | |
| 4000. |
Which of the followingg lens would you prefer to use while reading small letters found inn a dictionary? |
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Answer» A CONVEX lens of focal LENGTH 5cm |
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