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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.
| 5651. |
How much energy in joule is consumed when 100 units electricity are used? |
| Answer» SOLUTION :`3.6 XX 10^8J` | |
| 5652. |
A current carrying ______ can be used to magnetise an electromagnet. |
| Answer» SOLUTION :SOLENOID COIL | |
| 5653. |
A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of corrective lens to restore proper vision ? |
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Answer» SOLUTION :The propervisionof a mypic EYE can be restoredby USING concavelens of suitablepower . |
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| 5654. |
The effective resistance of three resistors connected in series is lesser than the lowest of the individual resistances. |
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| 5655. |
Consider the following circuits diagrams drawn by four students : The correct circuit diagram for studying the dependence of current on the potential difference across a resistor is : |
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Answer» A |
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| 5656. |
Choosethe wrongstatementout of thefollowing : |
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Answer» Magneticpoles always exsits in pairs |
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| 5657. |
When a 12V battery is connected across an unknown resistor, there is a current of 2.5mA in the circuit. Find the value of the resistance of the resistor. |
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Answer» Solution :Here voltage of BATTERY V=12V and current `I=2.5mA=2.5 times 10^-3 A` `therefore` RESISTANCE `R=V/I=12/(2.5 times 10^3)=4800 Omega=4.8 times 10^3 Omega=4.8 K Omega` |
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| 5658. |
Name and state the rule which determine the direction of magnetic field around a straight current carrying conductor. |
| Answer» Solution :Right Hand Thumb Rule : Imagine holding the CURRENT CARRYING straight conductor in your right hand such that the thumb POINTS towards the direction of current. Then the fingers of right hand wrap around the conductor in the direction of field lines of the MAGNETIC field. | |
| 5659. |
A boat which has a speed of 5 km per hour in still water crosses a river of width 1 km along the shortest possible path in fifteen minutes. The velocity of the river water in km per hour is :- |
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Answer» 1  `vecV_(br)=vecV_(b)-vecV_(R)` `V_(br)^(2)=V_(b)^(2)+V_(r)^(2)` `V_(b)^(2)=25-V_(r)^(2) "" ...(1)` `t=("distance")/(V_(b))rArr ` `(1)/(4) HR = (1)/(sqrt(25-V_(r)^(2)))` `V_(r)=3 km//h` |
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| 5660. |
Whatkind a quantiy is magneticfield ? How is thedirectionof magnetic fieldat pointis determind ? |
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Answer» Solution :Magneticfieldis a vectorquantity .It has bothdirectionand mangntidue. The directionof magneticfieldat a pointisdetermined by placinga SMALL COMPASS needleat thatpoint . The direction of magneticfieldis the directionin whciha NORTHPOLE of compass NEEDLE MOVES inside it . |
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| 5661. |
Whatis meant byspecificheat capacity ? Howwill proveexperimentallythat differentsubstancehave different speificheatcapacities? |
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Answer» SOLUTION :(i) The quantity of heatenergyrequiredto raise a temperatureofunit massofa substancethrough`1^(@)C`is calledspeificheatcapacity of a substance. (II) Three soildspheres of equal massesof materialiron,copperand lead are placedin boilingwaterfor same time.Afterremovingthensimultaneously,they are palcedon the wax trytogether . (iii) THESPHERE whichabsrobsmore heatcanmeltmorewax . (IV) Ironsphere meltsmorewaxand goesdeep into itray. Theleadsphere goes less deepinto themoltenwax. Thecoppersphere goes tointermediatedepth. (v) Thisindicatesthatthe heatabsorbed bydifferentmaterialdiffers. Theis specificheatcapacityof metals . (vi) Spefifcheatcapacityis denoted byletter 'c' . InCGSit is measured in `cal//g^(@)C`, whilein MKS , it ismeasuredin `j//kg^(@)C` . |
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| 5662. |
The refractive index of air with respect to glass is expressed as ""_(g)mu_(a)=(sini)/(sinr). (a) Write down a similar expression for ""_(a)mu_(g) in terms of the angles i and r. (b) if angle r=90^@, what is the corresponding angle i called ? (c) What is the physical significance of the angle i in part (b) ? |
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Answer» (b) critical ANGLE, (c) If angle of incidence exceeds the value of `i` OBTAINED in part (b), total internal reflection occurs. |
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| 5663. |
How will you explain the role of latent heat in the change of state of a substance? |
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Answer» Solution :When a solid is heated , initially , its temperature increases . Here , the heat absorbed by the body (substance) is used in increasing the kinetic energy of the particles (atomic , molecules, etc.) of the body as well as for doing WORK against the forces of attraction between them . As the heating is CONTINUED , at a certain temperature (melting point) , solid is converted into liquid . In this case , the temperature remains constant and the heat absorbed is used for weakening the bonds and conversion into liquid phase (liquid state) . This heat is CALLED the LATENT heat of fusion . When a liquid is converted into the gaseous phase (gaseous state) , at the boiling point , the heat absorbed is used for breaking the bonds between the atoms or molecules . This heat is called the latent heat of vaporization . Some solids , under certain conditions are directly transformed into the gaseous phase . Here the heat is absorbed but the temperature remains constant . The absorbed heat is used for breaking the bonds between atoms or molecules . This heat is called the latent heat of sublimation . In GENERAL , latent heat is the heat absorbed or given out by a substance during a change of state at constant temperature . In transformation from liquid to solid , gas to liquid and gas to solid , latent heat is given out by the body (substance) . |
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| 5664. |
Draw a graph to show the relation between current (I) and voltage (V) for conductors ? |
Answer» SOLUTION :
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| 5665. |
Whatis magnetic force ? |
| Answer» SOLUTION : Force EXPERIENCED by a current-carrying WIRE when placed in a magnetic FIELD or the force experienced by a CHARGED particle moving in a magnetic field. | |
| 5666. |
Why are forests considered biodiversity hot spots '? List twoways in which an individual can contribute effectively to the management of forests and wildlife. |
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Answer» Solution :Forests are considered biodiversity hot spots ' because large number of life forms (such as bacteria, fungi , fern , nematodes , insects, birds , reptiles , mammals , gymnosperms and angiosperms) are found there . Theseare the regions with large biodiversity of ENDANGERED species , many of them being highly endemic . Such regions are being SUBJECTED to large scale destruction and hence are called hot spots by ecologists. Ways in which an individual can contribute : (i)Not allowing cutting of trees. (ii)To promote ormake PEOPLE AWARE about the importance forests and wildlife. (iii)Not using wildlife products like FUR coat or any other named product. |
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| 5667. |
Website,movies and cartoon films inappropriate for children, are banned by the government. |
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| 5668. |
Is there any relationship of latent heat with regelation ? |
| Answer» Solution :YES, when ICE melts, heat is ABSORBED, but the temperature does not change. ALSO , when water refreezes, heat is GIVEN out, but the temperature does not change . This heat absorbed or given out is the latent heat. | |
| 5669. |
When we add water to quick lime we observe some changes. On the basis of those changes what can be concluded about the reaction between quick lime and water? |
| Answer» Solution :When water is added to quick lime, a white powder of slaked lime is formed. It means it is a COMBINATION reaction. Also a large AMOUNT of heat is RELEASED so it is an exothermic reaction. | |
| 5670. |
State the factors on which the heat produced in a current canying conductor depends. Give one practical application of this effect. |
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Answer» SOLUTION :H =`I^(2)Rt` Factors : square of current, RESISTANCE of the given conductor, TIME on which the current flows.Application : electric heating devices like electric iron or any other/electric bulblelectric fuse. |
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| 5671. |
Safety fuse wire should be made of : |
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Answer» Copper |
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| 5672. |
How it could have been saved from these disasters? Discuss with your friends in the classroom. |
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Answer» Solution :a. The DISASTERS SHOWN in the picture are natural disasters. b. Although it is difficult to predict such disasters, precautions can be taken to minimise the losses caused by such disasters. c. This requires proper planning for MANAGING disasters which are known to occur in a particular region. d. For regions which are prone to flooding, proper drainage arrangement, for water seepage should be provided. e. Railway lines must be constructed over bridges where possibility of submerging of railway trck is high. ltbr. f. Earthquake prone areas should have housed and other constructions which are built with materials that CASUSE less destruction. |
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| 5673. |
Why is series arrangement not used for domestic circuits? |
| Answer» Solution : In series arrangement, same CURRENT will FLOW through all the appliances which is not required and the EQUIVALENT resistance becomes HIGHER, hence the current drawn becomes less. | |
| 5674. |
If twoicecubesare pressedagainst eachothertheysticktogetherfirmlyaftersometimebecause _____. |
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Answer» TEMPERATUREOF theicecubesreduces . |
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| 5675. |
Draw a neat diagram of an AC generator. |
Answer» SOLUTION :
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| 5676. |
Sangeetha often confused the current and potential differences Ravi explained the terms by asking some questions. What would be those questions ? |
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Answer» Solution :1. Where do free electrons exists ? 2. What happens to the motion of electrons when the ENDS of the conductor are connected to the battery ? 3. What are the resposible for the transfer of energy ? 4. When do you say current is passing through a conductor ? 5. What is defined as the amount of charge crossing any cross section of the conductor in one SECOND ? 6. What is I ? What is its units ? 7. Where do the electrons GET energy for their motion ? 8. What is the work done by the electric FORCE on a unit charge ? 9. What is its potential difference ? 10. What is its units ? 11. If there is no potentia difference. what will happen to current ? 12. What the devices are used to measure current and voltage ? |
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| 5677. |
Ability of a body to maintain its state of rest or motion is called …………………… |
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Answer» MECHANICS |
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| 5678. |
Describe the behaviour of a wire undergradually increasing load. |
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Answer» Solution :Behviour of a wire under increasing load : Let a wire is susdpended at one end and loads are attached to the other end. When loads are GRADUALLY the following changes are noticed. 1. Proportionality limit (A) : When load is increased the elongation of the wire gradually increases. The MAXIMUM load upto which the elogation is directly pro- portional to the load is called propor- tionality limit (A). The graph frawn bet- ween load and extension is a straight line . So point A is called proportionality limit. In this region Hooke.s Law is obeyed. 2. Elastic limit (B) : If the load is increased above the proportionality limit the elongation is not proportional to the load. Hooke.s law is not obeyed. But it exgibits elasticity which means that it regains the original length if load is removed. The maximum load on the wire upto which it exhibits elasticity is called elastic limit (B in the gaph).  3. Permanent set (C) : If the load on the wire is increased beyond elastic limit say upto .C. , the elongation is not pro- portional to load. On removai of the load the wire does not regain its original length. in figure permanent set is given by OP. So OP is called permanent set. 4. Point of ultimate tensile strength (D) : If the load is further increased, upto .D. then strain increases rapidly even though there is no INCREASE in stress. At this stage the restoring forces seems to be subdued to then deforming forces. Elongation without increase in load is called creeping . This behaviour of metal is called yielding. 5. Fracture point (E) : If the load is incre- ased beyond yield point the elongation is very RAPID, even for small changes in load the wire becomes thinner and breaks. This is shown as E. The breaking force per unit area is called breaking stress. |
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| 5679. |
The electric current in a closed circuit always flows from the ___________ terminal of the electric cell to __________ terminal. |
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Answer» `-ve` to `+ve` |
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| 5680. |
The elements whose atomic number is more than 83 undergo __________ radioactivity. |
| Answer» SOLUTION :spontanous PROCESS | |
| 5681. |
A convex lens of focal length 10 cm is palced at a distance of 12 cm from a wall. Calculate the distance from the lens where an object can be placed so as to form its distinct real image on the wall. |
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Answer» SOLUTION :`v=+12cm, f=+10cm` `1/v-1/u=1/fimplies1/12-1/u=1/10` `u=-60cm` |
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| 5682. |
If earth contracts to half of its present radius what would be the length of the day at equator ? |
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Answer» Solution :`I_(1) =2/5 MR^(2) rArr I_(2) = 2/5 M(R/2)^(2) rArr I_(2) = I_(1)/4` `L=I_(1)omega_(1) = I_(2)omega_(2)` or `I(2PI)/(T_(1)) =1/4(2pi)/(T_(2))` or `T_(2) = T_(1)/4 = 24/4 =6` hours. |
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| 5683. |
___________ is used to select the magnitude of current through a circuit. |
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| 5684. |
What is thermal equilibrium ? |
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Answer» Solution :(i) TWO or more physical systems or bodies are said to be in THERMAL equilibrium if there is no NET flow of thermal energy between the systems. (ii) If two bodies are said to be in thermal equilibrium, then they will be at the same TEMPERATURE. |
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| 5685. |
In Q 64 above , suppose the cable breaks , then the weighing machine will read |
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Answer» more than the weight of the body This weight ACTS on the weighing machine which offers a reaction R, given by the READING of the weighing machine. (i)When the elevator is at rest or moving with uniform velocity , upwards or downwards , apparent weight R = mg , which is the actual weight . (ii)When the elevator is accelerating downwards with ACCELERATION a , we have mg - R =ma or R= m(g-a) In this case , apparent weight becomes less. (iii) When the elevator is accelerating upwards with acceleration a , we have R- mg=ma or R=m(g+a) In this case , apparent weight becomes more . (iv)If a=g,R=m(g-g)=0 So , the apparent weight of a person in an elevator falling down FREELY with an acceleration (=g) is zero . |
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| 5686. |
(i) A concave mirror produces three times enlarged image of an object placed at 10 cm in front iof it. Calculate the focal length of the mirror. (ii) Show the formation of the image with the help of a ray diagram when object is placed 6 cm away from a pole of a convex mirror. |
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Answer» SOLUTION :(i) `m=-V/u,u=-10cm` `-3=(-v)/(-10)` `v=+30` `=+3xx-10=-30cm` `-1/30-1/10=1/f` `f=-7.5cm` 
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| 5687. |
Spontanous radioactivity is also known as …… |
| Answer» SOLUTION :NATURAL RADIOACTIVITY | |
| 5688. |
State applications of heating effect of electric current. |
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Answer» Solution :Domestic appliances whose working is BASED on the heating effect of electric current : (1) Electric HEATER (2) electric iron (3) electric oven (4) electric TOASTER (5) electric kettle (6) electric geyser (7) FUSE. Some other applications of heating effect of electric current : (1) electric bulb (2) electric furnace (3) in industry for soldering, welding, cutting, drilling (4) in surgery for cutting tissues with a finely heated platinum wire. |
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| 5689. |
The geometricradiusof the Earth is maximum in the equatorial region and minimum in the polar region . |
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| 5690. |
A man spend 6-4 KJ energy in displacing a body by 64 m in the direction in which he applies force,in 2.5 s.Calculate :(i)theforce applied,and (ii)the power spent (in H.P) by the man |
| Answer» SOLUTION :(i)100 N, (II)3-43 H.P | |
| 5691. |
Orange light of wavelength 6600 Å travelling in air gets refracted in water. If the speed of light in air is 3xx10^(8)ms^(-1) and refractive index of water is 4/3, find : (i) the frequency of light in air, (ii) the speed of light in water, and (iii) the wavelength of light in water. |
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Answer» Solution :Given: `lamda_(air)=6600Å=6600xx10^(-10)m` `c=3XX10^(8)ms^(-1),mu=4//3` (i) From relation `c=flamda` (in air) Frequency of LIGHT in air `f_(air)=(c)/(lamda_(air))` or `f_(air)=(3xx10^(8))/(6600xx10^(-10))` `=4*54xx10^(14)Hz` (ii) From relation `mu=(c)/(V)` Speed of light in water `V=(c)/(mu)=(3xx10^(8))/(4//3)` `=2*25xx10^(8)ms^(-1)`. (iii) Since the frequency of light remains unchanged in refraction, so `f_(water)=f_(air)=4*54xx10^(14)Hz` Now speed of light in water `V=f_(water)xxlamda_(water)` `THEREFORE` Wavelength of light in water `lamda_(water)=(V)/(f_(water))=(2*25xx10^(8))/(4*54xx10^(14))` `=4*95xx10^(-7)m` or 4950 Å Alternative: `lamda_(water)=(lamda_(air))/(mu_(water))=(6600Å)/(4//3)=4950Å` |
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| 5692. |
The magnetic field produced by a coil of n turns, at its centre, is n times as large as that produced by a single turn.Give reason to justify this statement |
| Answer» Solution :If a coil has several turns, current FLOWS in these turns in the same direction and HENCE, the magnetic FIELD PRODUCED is also in the same direction. So, the field adds up. Thus, the total magnetic field is DIRECTLY proportional to the number of turns. | |
| 5694. |
Draw a neat labelled diagram of Hope's apparatus. Explain how this apparatus can be used to demonstrate anomalous behaviour of water.Drawa graph of temperatureof water against time. |
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Answer» Solution :Figure shows Hope's apparatus. Initially, the cylindrical container in Hope'sapparatus is filled with water at about `12^(@)C `and the flat bowl is filled with a freezing mixture of ice and salt. The temperature of water in the upperpart of the container `( T_(2))` is recorded by thermometer `T_(2)`and that of water in the lower part of the container `( T_(1))` is recorded by thermometer `T_(1)`. Figure shows variation of temperature of water with time. Initially, both the thermometers show the same temperature(say,`12^(@)C)`. In a short time, the temperature shown by the lower thermometer starts decreasing, while the temperature shown by the upper thermometer does not change very much. This process continues till the temperature till the temperature shown by the lower thermometer falls to `4^(@)C ` and remains CONSTANT THEREAFTER . This shows that in the temperature range `12^(@)C ` to `4^(@)C`, density of the water in the central part of the container goes on increasing and hence the water sinks to the bottom.It means that water contracts, i.e., its volume decreases as its temperature falls from `12^(@)C ` to `4^(@)C`.  Asthe temperature of the water in the central part of the container becomes less than `4^(@)C `, the temeprature shown by the upper thermometer beings to fall rapidelyto `0^(@)C`. But the temperature shown by the lower the thermometer remains constant `( 4^(@)C)` . Later, the reading shown by the lower thermometer decreases to `0^(@)C `. In the temperature range `4^(@)C ` to `0^(@)C ` , the water moves upward. This shows that the denisty of water goes on decreasing in this range. It means that water expands, i.e., its volume increasesas its temperature falls from `4^(@)C ` to `0^(@)C`. Thus, the volume of a given mass of water is minimum at `4^(@)C ` , i.e., the density of water is maximum at `4^(@)C `.  In figure, the POINT of INTERSECTION of the two curves shows the temperature at which the density of water is maximum .This temperature is `4^(@)C`. |
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| 5695. |
One roentgen is equal to _________________ disintegrations per second. |
| Answer» SOLUTION :`3.7 XX 10^(10)` | |
| 5696. |
Magnetic field lines around a current carrying straight conductor are concentric circles. |
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| 5697. |
Stateone difference betweenthe wires used in the element of an electric heater and in a fuse . |
| Answer» SOLUTION :Themeltingpointof the materialof the wire USED in a heater elements is HIGH whilea fuse wirehas low MELTING point . | |
| 5698. |
Define object distance and image distance. |
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Answer» SOLUTION :1.The OBJECT distance is the distance of object from the POLE. 2. the distance is the distance of IMAGE from the pole. |
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| 5699. |
The value of solar constant is : |
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Answer» 1.4 KWH |
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| 5700. |
Ground water will not be depleted due to |
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Answer» afforestation |
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