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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.
| 7751. |
A rocket is fired from the earth towards the sun. At what distance from the earth's centre is the gravitational force on the rocket zero? Mass of the sun=2xx10^(30)kg, mass of the earth=6xx10^(24)kg. Neglect the effect of other planets etc. (orbital radius=1.5xx10^(11)m). |
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Answer» Solution :Given `M_(s)=2xx10^(30)kg`. `M_e= 6xx10^(24)kg, r=1.5xx10^(11)m` LET m be the mass of the rocket. Let at distance x from the earth, the GRAVITATIONAL force on the rocket be zero. Then at this distance, Gravitational PULL of the earth on the rocket = gravitational pull of the sun on the rocket. `(GM_e m)/(x^2)= (GM_e m)/((r-x)^2)" or "((r-x)^2)/(x^2)= (M_s)/(M_e)` or `(R-x)/(x)= sqrt((M_s)/(M_e))= sqrt((2xx10^(30))/(6xx10^(24)))= (10^3)/(sqrt(3))=577.35` or `r-x=577.35x` or `578.35x=r=1.5xx10^(11)` or `x=(1.5xx10^(11))/(578.35)=2.59xx10^(8)m`. |
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| 7752. |
Nuclear fusion is possible only at an extremely high temperature of the order of ____________K. |
| Answer» SOLUTION :`10^(9)` to `10^(9)` | |
| 7753. |
How many refractions does a ray of light suffer on passing through a glass prism ? |
| Answer» SOLUTION :On PASSING through a glass prism, a ray of light undergoes two refractions. At ONE rectangular SURFACE of prism, light suffers refraction in going from RARER to denser medium and on other rectangular surface, light undergoes refraction from denser medium to rarer medium. | |
| 7754. |
Do all cartesian sign conventions are applicable in each case of spherical lens as in mirrors? |
| Answer» Solution :Yes, all DISTANCE are MEASURED from the optical CENTRE of the lens. CONVENTIONALLY, the object is PLACED on the left side of the lens. | |
| 7755. |
How is the type of curttnt that we receive in domestic circuit different from the one that runs a clock ? |
| Answer» SOLUTION :In domestic CIRCUIT, it is A.C. while clock cell GIVES D.C. | |
| 7757. |
Collect the information about masses and radii of all the planets of our solar system and determine the escape velocity of those planets. |
Answer» SOLUTION :
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| 7758. |
If the image formed by a mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it ? Draw a ray diagram to justify your answer. Where and why do we generally use this type of mirror ? |
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Answer» Solution :Only a convex MIRROR always form an erect and diminished image behind the mirror between is pole and FOCUS point for all positions of the object placed in front of the mirror. A ray diagram showing the image formatioon of an object AB is shown here.  A convex mirror is used as a rear VIEW mirror in automobiles because it gives erect and diminished images of vehicles coming from behind. As a result, it HELPS the driver in having a much wider FIELD of view. |
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| 7759. |
The SI unit of resistivity is ……………. . |
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Answer» `OMEGA` |
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| 7760. |
Calculate the number of molespresent in 60 g of NaOH. |
| Answer» SOLUTION :NUMBER of MOLES `= ("MASS")/("MOLECULAR mass")= 2/40 = 0.05`. | |
| 7761. |
Pre-disaster management: |
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Answer» Solution :The management measures taken before onset of a DISASTER is called pre-disaster management. In pre-disaster management, complete PREPARATION and PLANNING to face any type of disaster is done. For this purpose, following steps are taken. (1) Identifying the areas where the disaster can strike. Such disaster-prone areas are to be thoroughly studied. (2) Through predictive intensity maps and hazard maps, the information is collected about the intensity of disaster and probable sites of disasters respectively. (3) Special training for disaster management is given to the concerned people. (4) The mass awareness is CREATED about disaster management through training programmes, mass media and internet, etc. |
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| 7762. |
Explain about the centre of mass of earth moon system and its rotation around the sun. |
| Answer» Solution :The interaction of EARTH and moon does not effect the motion of centre of mass of earth and moon system AROUND the sun. The gravitational force between earth and moon is INTERNAL force. Internal forces cannot change the position of centre of mass.The external force acting on the centre of mass of earth and moon system is force between the sun and C.M. of earth, moon system. Motion of centre of mass depends on 'external force. Hence, earth moon system continues to move in an elliptical path around the sun. It is IRRESPECTIVE of rotation of moon around earth. | |
| 7763. |
Posture and balance of the body is controlled by |
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Answer» PONS |
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| 7764. |
Describe the steps involved in obtaining biogas and explain what is meant by anaerobic decomposition. |
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Answer» Solution :Following steps are involved in OBTAINING biogas: (i) Mixing (slurry of cattle-dung and WATER). (ii) Digesting (cattle-dung undergoing DECOMPOSITION by anaerobic bacteria). (iii) Formation of biogas (mixture of methane, `CO_(2) , H_(2)and H_(2)S`). (iv) Spent slurry (residue left after the formation of biogas). The process by which the biomass change into biogas in the ABSENCE of air due to an anaerobic microorganisms is termed as an anaerobic decomposition. |
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| 7765. |
How has the traditional use of wind and water energy been modified for our convenience ? |
| Answer» Solution :The windmills which have been traditionally USED are converted to wind energy farms, which contain a LARGE number of windmills to increase our energy OUTPUT. HYDROPOWER plants are now associated with dams to PRODUCE electricity. | |
| 7766. |
The work done in moving a unit positive charge across two points in an electric circuit is a measure of |
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Answer» Current |
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| 7767. |
"Derive"P=I^(2)R. |
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Answer» Solution :1. Consider that a charge (Q) Coulomb passes through a point A. MOVES to point B in time interval 't' SECONDS. 2. Let V be the potential difference between the points A and B. 3. The work done by electric field in time 't' is GIVEN by W = QV-(1) 4. The work is equal to the energy lost by the charge while passing through the conductor for time 't'. 5. Energy lost by the conductor in `sec = (W)/(t).` From (1), `(W)/(t)=(QV)/(t)-(2)` We know, `(Q)/(t)=Iand(W)/(t)=P("POWER")` Then `(2)rArrP=VI-(3)` This equation can be used to calculate power consumption by any electric devie that is connected in a circuit. From Ohm's law V = I R `therefore(3)rArrPI^(2)R. (or)(V^(2))/(R)-(4)` 6. To know the power that can be EXTRACTED from battery or any source can be calculated by `P=epsilonI.` Whose `epsilon` is the emf of the battery or source. 
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| 7768. |
Nishant is a lazy boy. He doesn't like to brush his teeth instead he rinses his mouth with water. His mother makes sure that he brushes his teeth twice a day. Answer the following questions based on the above situation: (i) Why does Nishant's mother insist on brushing teeth twice a day? (ii) How is a toothpaste better than just water, for cleaning teeth? (iii) What values are promoted by Nishant's mother? |
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Answer» Solution :(i) We should BRUSH our teeth twice a day as bacteria present in the mouth, produce acids by DEGRADATION of sugar and FOOD particles remaining in the mouth after eating. (ii) The best way to prevent this is to CLEAN the mouth using toothpastes which are generally basic. These can neutralise the excess acid and prevent tooth decay. (iii) Awareness, caring, HEALTH consciousness. |
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| 7769. |
An aged person is having difficulty in seeing nearby objects clearly. Name this defect of vision. |
| Answer» SOLUTION :PRESBYOPIA. | |
| 7770. |
A force of 36 dynes is inclined to the horizontal at an angle of 60^@. Find the acceleration in a mass of 18 g that moves in a horizontal direction. |
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Answer» SOLUTION :F=36 DYNE at an angle of `60^(@)` `F_(x)=F COS 60^(@)=18"dyne"` `F_(x)=ma_(x)` So, `a_(x)=(F_(x))/(m) =1 cm//s^(2)` |
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| 7771. |
Name two energy sources that you would consider to be renewable. Give reasons. For your choices. |
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Answer» SOLUTION :1. Solar energy since it available in ample and is absolutely FREE. 2. WIND energy is easily available and is free. It can be USED in very remote areas. |
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| 7772. |
How does a solenoid behave like a magnet? Can you determine the north and south poles of a current carrying solenoid with the help of a bar magnet? |
| Answer» Solution :When electric current flows through a SOLENOID, magnetic field is set up around the solenoid. The pattern of the magnetic field is same as that of the magnetic field of a bar magnet. One end of the solenoid behaves as NORTH POLE and the other end of the solenoid behaves as south pole. To determine the north and south poles of a current CARRYING solenoid with the help of a bar magnet, suspend it with a strong thread. Now bring the north pole of a bar magnet towards one end of the solenoic. If the solenoid attracts towards the magnet then the face of the solenoid is south pole. If the bar magnet moves AWAY from the solenoid, then the face of the solenoid is the north pole. | |
| 7773. |
In a village in Karnataka , people started cultivating crops all around a lake which was always filled with water . They added fertilisers to their field in order to enhance the yield . Soon they discovered that the water body was completely covered with green floatingplants and fishes started dying in large numbers. Analyse the situation andgive reasons for excessive growth of plants and death of fish in the lake. |
| Answer» Solution :Since people USED EXCESSIVE fertilisers in the fields , they were carried down to the lake during rains As many fertilisers contain phosphates and nitrates , the water body became ENRICHED with these chemicals . Thesechemicals promote excessive growth of aquatic plants and the SURFACE of water was completely covered with plants (eutrophication).Depletion of light in the water body and insufficient AVAILABILITY of dissolved oxygen and nutrients resulted in the death of fish. | |
| 7774. |
An example observed as a consequence of attaining the dew-point temperature is |
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Answer» droplets on the leaves after rain shower. |
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| 7775. |
State the nature, position and relative size of the image formed by a convex mirror when object is (i) at infinity and (ii) between infinity and pole of the mirror. Draw ray diagrams too. |
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Answer» Solution :Image formed by a convex MIRROR. `{:("S.No.","Position of the object","Position of the image","SIZE of the image","Nature of the image"),(1.,"At INFINITY","At the principal focus","HIGHLY diminished","Virtual and erect"),(,,"(F) behind the mirror","(point sized)",),(2.,"Between infinity and","Between pole (P) and","Diminished","Virtual and erect"),(,"the pole (F)of the mirror","principal focus (F)",,),(,,"behind the mirror",,):}` |
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| 7776. |
What phenomenon causes twinkling of stars on a clear night ? |
| Answer» SOLUTION :STARS twinkle on account of atmospheric REFRACTION. | |
| 7777. |
Draw the symbols of the following. Rheosistat |
Answer» SOLUTION :
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| 7778. |
What do you understand by a sound wave ? |
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Answer» SOLUTION :1) Sound is produced from a vibrating body. 2) It travels through AIR in the form of a wave. 3) Sound waves are LONGITUDINAL. |
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| 7779. |
Assume that you are interviewing Sunita Williams. Prepare a questinnaire and also the answers. |
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Answer» SOLUTION :The QUESTIONNAIRE for interview of sunita williams: (a) Con you cook food in space ? What do you eat in space ? Does it taste same as on earth? (b) Do you have to keep HOLDING to something when you are outside the space station? Doesn't that make you afraid of flosting away in the space during your SPACEWALKS ? (c) What is the differnce between the sky you see from the space station and from the earth? (d) Do the clocks in your comuters on the space station SHOW the same time as that on the earth? |
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| 7780. |
The volume of 50 g. of a substance is 20cm^(3). If the density of water is 1g//cm^(3), will the substance float or sink ? |
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Answer» Solution :`"Density of SUBSTANCE"=("Mass of substance")/("Volume of substance")=CANCEL(50^(5))/cancel(20_(2))=-2.5g//cm^(3).` The density of substance of is more than water so the substance SINKS in the water. |
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| 7781. |
How are monocots different form dicots? |
| Answer» SOLUTION :Monocots have single cotyledons WHEREAS DICOTS have DOUBLE cotyledons. | |
| 7782. |
The interacting particles of the medium is called as ____________. |
| Answer» SOLUTION :SCATTERER | |
| 7783. |
For a spherical mirror, (1)/(v) + 1/u = (1)/(f) =2/R, where u= distance of object from pole of mirror v= distance of image from pole of mirror f= focal length of mirror R= radius of curvature of mirror. This formula is known as mirror formula. It is applicable equally to convex mirror as well as concave mirror. Read the above passage and answer the following questions : (i) When we change u by moving the object, how is focal length f, affected? (ii) The radius of curvature of a spherical mirror is 40 cm. What is its focal length? (iii) Focal lenght of a mirror depends neither on u, nor on v. It depends only on radius of curvature of the mirror. What values of life do you learn from this fact? |
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Answer» Solution :(i) When we change U, by moving the object, distance of IMAGE v changes. But FOCAL length of mirror, i.e., f is not affected. (ii) Here, `R=40cm`, `f=R/2 =40/2 = 20`cm. (iii) In day to day LIFE, an object is like a SITUATION that comes up and image is like the response we give to it. We are like a mirror. Our nature/curvature determines our focal length. Response to a particular situation will depend upon our nature. One the contray, our nature/focal length is not affected by the situation that comes up. |
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| 7784. |
Define th SI unit of electric current. (or) What is one second in SI system of units? (or) Define one ampere (S.I standard for current) |
| Answer» SOLUTION :CORRECT Statement : The SI unit of electric CURRENT is Ampere. | |
| 7785. |
Space missions have been undertaken for close observation of various objects inour ... .. ... ..... . |
| Answer» SOLUTION :SOLAR SYSTEM | |
| 7787. |
A slide showing several Amoeba was given to a student and was asked to focus the Amoeba undergoing binary fission. What will the student look for to correctly focus on a diving Amoeba ? |
| Answer» SOLUTION : STUDENT will look for an Amoeba with elongated nucleus with a CONSTRICTION in the middle. | |
| 7788. |
How much work is done by a coolie walking on a horizontal platform with a load on his head? |
| Answer» Solution :W=0 as his DISPLACEMENT is along the horizontal direction and in order to BALANCE the load on his head, he applies a force on it in the upward direction equal to its weight. Thus ANGLE between force and displacement is ZERO. | |
| 7789. |
Explain the term of "fissile material' Give example. |
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Answer» Solution :A fissionable material is a radioactive element, which undergoes FISSION in a sustained manner when it ABSORBS a neutron. It is also termed as .fissile material.. E.g. `U^(235)`, PLUTONIUM (`Pu^(239)` and `Pu^(241)`) |
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| 7790. |
Why are Constantan and Manganin used for making standard resistors? |
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Answer» Solution :The resistivity of Constantan and MANGANIN is moderate and almost INDEPENDENT of temperature. HENCE, these materials are used for MAKING STANDARD resistors. |
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| 7791. |
The process of breaking up of heavier nucleus into smaller nuclei with release of large amount of energy is called ___________. |
| Answer» SOLUTION :NUCLEAR FISSION | |
| 7792. |
Which is the wrong statement out of the following? |
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Answer» A CONCAVE mirror can give a virtual IMAGE. |
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| 7793. |
What is scattering of light ? How does it take place in earth's atmosphere ? How does colour of scattered light depend on the size of scattering particles ? |
| Answer» Solution :Scattering of light is the phenomenon of INTERPLAY of light with minute sized particles. As a result of such interplay light spreads in DIFFERENT directions and also becomes visible. The earth.s atmosphere is a heterogeneous mixture of minute particles including smoke, TINY water droplets, suspended dust particles and molecules of air. When a BEAM of light strike such fine particles, the path of the beam becomes visible DUE to scattering. The colour of the scattered light depends on the size of the scattering particles. Very fine particles scatter mainly blue light but particles of larger size scatter light of longer wavelengths also. For arge enough size of scattering particles the scattered light may appear white. | |
| 7794. |
What is the advantage of having conical openings in horns, megaphones, etc? |
| Answer» Solution :The conical openings in horns, megaphones ETC, will GUIDE the reflections SOUND waves in forward and spreads towards the AUDIENCE. | |
| 7796. |
Body temperature of reptiles is not constant. |
| Answer» SOLUTION :Reptiles are cold - blooded ANIMALS. The thermoregulatory system is not there in their bodies. Their body temperatures, FLUCTUATE as per the environmental temperatures. THEREFORE , the body temperature is not maintained at CONSTANT level in reptiles. | |
| 7798. |
The specific heat of gas |
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Answer» has only two values `Cp` & `Cv` |
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| 7799. |
What could be the reason for better reflection of sound by rough surfaces than polished surfaces? |
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Answer» Solution :1) SOUND reflects better on rough SURFACES than POLISHED surfaces. 2) The rough SURFACE reflects sound in all directions, so it can reach in MANY directions. |
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| 7800. |
Your friend has developed the hobby of snapping selfies. |
| Answer» Solution :The habit of CONTINUOUSLY taking selfie is BAD. It SHOWS that the friend is constantly thinking of himself only. His self-centredness is to be removed by couselling him. The reason behind this behaviour should also be understood . He should be diverted and motivated to TAKE some other tasks so that his habit can be Iessened. Taking selfies is not a hobby. It is a bad habit if someone is REPEATEDLY engaged in it. | |