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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.
| 8451. |
Explain reversible and irreversible processes . Describe the working of Carnot engine . Obtain an expression for the efficiency . |
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Answer» Solution :Reversible process : In reversible process a thermodynamic system can be retraced back in opposite direction to the changes that take place in the direct process or in forward process . A reversible process is only an ideal concept . Examples for reversible process : 1) Peltier effect and Seebeck effect . 2) Fusion of ice and vapourisation of water . Irreversible process : A thermodynamic process that cannot be taken back in oposite direction is called "irreversible process." Examples : 1) Work done against frition 2) Magnetization of materials . Carnot's Engine : Carnot's engine works on the PRINCIPLE of reversible process with-in the temperatures`T_(1) and T_(2)` It consists of four continuous PROCESSES . Total process is known as Carnot Cycle . Step 1 : In carnot cycle the 1st step consists ofisothermalexpansionof gases . So TEMPERATURE T is constant , P ,V changes areshown as`P_(1)V_(1)T_(1)overset("to")rarrP_(2)V_(2)T_(2)` Work done in isothermal process `W_(1rarr2)=Q_(1)-muRT_(1)log_(e)((V_(2))/(V_(1)))""....(1)` Step : 2 In this stage gases will expand adiabatically . So energy to the system Q is constant . So , P,V relation is `P_(2)V_(2)T_(1)overset("to")rarrP_(3)V_(3)T_(2)` Work done in adiabaticallyprocess `W_(2rarr3)=(muR(T_(1)-T_(2)))/(gamma-1)"" ...(2)`  Step 3 : In this stage gases will be compressed isothermally , So`P_(1)V` changes are `P_(3)V_(3)T_(2)overset("to")rarrP_(4)V_(4)T_(2)` Work done in isothermal compression `W_(3rarr4)=Q_(1)-muRTlog_(e)((V_(3))/(V_(4)))""....(3)` Step 4 : In the fourth stage the gas suffers adiabatic compression and returns to original stage . So , P,V changes are`P_(4)V_(4)T_(2)overset("to")rarrP_(1)V_(1)T_(1)` Work done`W_(4rarr1)=(muR(T_(2)-T_(1))/(gamma-1)"" ...(4)` Total work done `W=muRT_(1)log((V_(2))/(V_(1)))` `+(muR)/(gamma-1)(T_(1)-T_(2))-muRT_(2)log(V_(3)/(V_(4)))-(muR)/(gamma-1)(T_(1)-T_(2))` `therefore W=muRT_(1)log((V_(2))/(V_(1)))-muRT_(2)log(V_(3)/(V_(4)))` The total work done `W=Q_(1)-Q_(2)` i.e., the difference to heat energy ABSORBED from source and heat energy given to sink Efficiency of Carnot engine `eta=("work done by Carnot engine")/("heat energy supplied")` `thereforeeta=(Q_(1)-Q_(2))/(Q_(1))" or " eta=1-(Q_(2))/(Q_(1))=1-(T_(2))/(T_(1))` |
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| 8452. |
Explain whyit is easier to pull a lawn mover than to push it |
Answer» SOLUTION :While pulling a lawn MOVER , force is applied upwards along the HANDLE . The vertical component of this force is upwards and reduces the effective WEIGHT of the mover, Fig (a) . While pushing a lawn mover , force is applied downwards along the handle . The vertical component of this force is downwards and increases the effective weight of the mover , Fig (b) . As the effective weight is lesser in case of pulling than in case of pushing , there-fore, "pulling is easier than pushing ".
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| 8453. |
The maximum velocity (in m/s) with which a car driver must transverse a flat curve of radius 150 m and coefficient of friction 0.6 to avoid skidding is |
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Answer» 60 |
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| 8454. |
Which of the following never ending resource ? |
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Answer» Land |
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| 8455. |
The numerical ratio of displacement and distance for a moving object is |
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Answer» ALWAYS LESS than 1 |
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| 8456. |
State the factors on which the resistivity of a material depends. |
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Answer» Solution :Resistivity of a MATERIAL depends on (1) nature / type of material. (2) temperature of the material. (3) the pressure exerted on the material at small extent. Resistivity of METALLIC substances increases with temperature while resistivity of semi-conductor substances decreases with temperature. Resistivity of alloys increases very slowly with temperature than in case of METALS. In other words one can say that, as resistivity of alloys is 100 times than that of pure metals, it is approximately independent of temperature. Insulators have practically no free electrons and as such have a very high resistivity, which decreases slowly with RISE in temperature. |
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| 8457. |
Linear expansion: Longitudinal expansion:: Superficial expansion:_________. |
| Answer» SOLUTION :AREAL EXPANSION | |
| 8458. |
Rite the mirror formula |
| Answer» SOLUTION :1/v+1/u=1/f | |
| 8459. |
One megawatt is equivalent to ............ |
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Answer» `10^2` W |
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| 8460. |
The mass and volume of a body are 4.237 g and 2.5 vm^(3), respectively. The density of the material of the body in correct significant figures is |
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Answer» `1.6048 G CM^(-3)` |
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| 8461. |
The average speed between B to C is |
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Answer» 1.5 m/s |
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| 8462. |
Nametwo devices whichwork on the principleof elctromagneticinduction. |
| Answer» Solution :ELECTRIC GENERATION , TRANSFORMER etc., workon the PRINCIPLEOF electromagneticinduction . | |
| 8463. |
State the condition under which a light ray passes undeviated through a lens. |
| Answer» Solution :When the incident ray passes through the OPTICAL CENTRE of a LENS, it passes undeviated. | |
| 8464. |
Explain the term with example : Structural isomerism |
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Answer» SOLUTION :The phenomenon in which COMPOUNDS having different STRUCTURAL formulae have the same molecular formula is called structural isomerism . Butane is REPRESENTED by two different compounds as their structural formulae are different . These two different structural formulae have the same molecular formula i.e. `C_(4)H_(10)`. 
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| 8465. |
In the experiment to show that a current carrying conductor when placed in the uniform magnetic field experiences a force. Whathappens when: the direction of current is perpendicular to the direction of magnetic field ? State your observation. |
| Answer» Solution :When the DIRECTION of CURRENT is perpendicular to the direction of MAGNETIC FIELD, then the rod will experience maximum FORCE. | |
| 8466. |
In the experiment to show that a current carrying conductor when placed in the uniform magnetic field experiences a force. Whathappens when: you reverse the terminals of the battery ? |
| Answer» SOLUTION :On reversing the TERMINALS of the BATTERY, the deflection of ROD will be in opposite DIRECTION. | |
| 8467. |
No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be |
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Answer» PLANE |
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| 8468. |
Name and define S.l. unit of resistance. Calculate the resistance of a resisto:r if the current flowing through it is 200 mA, when the applied potential difference is 0.8 V. |
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Answer» Solution :The SI unit of resistanre is ohm. One ohm is the RESISTANCE offered by a CONDUCTOR when the CURRENT passing through it is one AMPERE and the POTENTIAL difference across its ends is one volt. By Ohm.s law V = IR `R=(V)/(I) =(0.8V)/(0.2A) =4 ` ohm |
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| 8469. |
The change in focal length of an eye lens is caused by the action of the |
| Answer» Solution :ciliary muscles | |
| 8470. |
We often observe domestic waste decomposing in the bylanes of our home . Listfour ways to make the residents aware that the improper disposal ofwastes is harmful to the environment and make the residents aware that the improper disposal of wastes is harmful to the environment and also for their own health. |
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Answer» Solution :Residents can be made aware by spreading awareness by different ways : (i)ORGANISING street plays, (ii)DISTRIBUTING PAMPHLETS to the residents, (iii)reuse/ recycleof the waste PRODUTS, (iv)calling meeting of residents , welfare society/association of the locality, (v) advertisements through TV/ radio, (vi)putting posters/hoardings, (VII)segregation of thenature of the waste . |
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| 8471. |
Give an account on vascular bundle of dicot stem. |
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Answer» Solution :(a) The VASCULAR bundles of DICOT stem (Eg, sunflower) are conjoint, collateral, endarch and open. They are arranged in the FORM of a ring around the pith. (b) The THREE basic tissue system in flowering PLANTS are (i) Dermal or Epidermal tissue system (ii) Ground tissue system (iii) Vascular tissue system |
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| 8472. |
Two glass tumblers have been stuck together (one into the other). They can be separated by |
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Answer» placing hot WATER in the inner TUMBLER |
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| 8473. |
Select the correct statement about themagnetic field lines : |
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Answer» Magnetic field lines start from N - and S- polesof a magnet and GO upto infinity |
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| 8474. |
What is environment? |
| Answer» Solution :The physical, CHEMICAL and biological FACTORS which influence an organism collectively is CALLED as ENVIRONMENT. | |
| 8475. |
What is natural environment made up of ? |
| Answer» SOLUTION :Natural environment is made up of air,ATMOSPHERE, WATER,land, LIVING organisms,ETC. | |
| 8476. |
What do you mean by pole of a spherical mirror ? |
| Answer» SOLUTION :The CENTRE point of the reflecting SURFACE of a spherical mirror is called its POLE. | |
| 8477. |
If fuses of 250 mA, 5A and 10 A were available, whichone wouldbe the most suitablefor protectingan amplifer ratedas 240 V, 180 W? |
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Answer» SOLUTION :1 A Because , the currentratingof an amplifier is `I = (P)/(V) = (180 W)/(240 V) = (3)/(4)A = 0.75 A ` Hence, the fuseof 1 A ratingis mostsuitablecomparedtoothergive fuses for SAFETY purpose . |
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| 8478. |
Diffrentiate between conduction, convection and radiation. |
Answer» SOLUTION :
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| 8479. |
Which of the following ray diagrams is correct for the ray of light incident on a concave mirror as shown in figure? |
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Answer» A |
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| 8480. |
Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V. |
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Answer» Solution :`q = 96000 C ` t=1 h `=60xx60 = 3600 ` SEC V= 50 V Heat produced = work DONE `H= QV= 96000 xx50 = 4.8xx10^(6)J` |
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| 8481. |
An insect craws a distance of 3m along north in 6 seconds and then a distance of 4 m along east in 9 seconds. Then the average velocity of the insect is |
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Answer» `3 ms^(-1)` |
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| 8482. |
Genotypic ration of monohybrid cross |
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Answer» Solution :Monohybrid CROSS : `"PHENOTYPIC Ratio " :UNDERSET("(TALL)")(3):underset("(dwarf)")(1)` Genotypic Ratio: `underset("Tall")underset("Homozygous :")(" :1")underset("Tall")underset("Hoterozygous : ")(" :2")underset("drarf")underset("Homozygous")(" :1")` |
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| 8483. |
A small pebble tied at one end of a string in placed near the periphery of a circular disc, at the centre of which the other end of the string is tied to a peg. The disc is rotating about an axis passing through its centre. (a) What will be your observation when you are standing outside the disc? Explain. (b) What will be your observation when you are standing at the centre of the disc? Explain. |
| Answer» Solution :(a) The pebble moves in a CIRCULAR path because the TENSION in the string provides the REQUIRED CENTRIPETAL force. (b) The pebble is stationary just in front because the centrifugal force on the pebble balances the tension in the string. | |
| 8484. |
What is the voltage of electricity supplied to the distribution transformer? |
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Answer» |
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| 8485. |
Which city had the maximum coliform count in Ganges water ? |
| Answer» SOLUTION :KANNAUJ and kanpur (Most Probable NUMBER 1400/500 ML) | |
| 8486. |
Fill in the blanks and explain the statements with reasoning:The initial velocity ( during launching) of the Mangalyaan must be greater than .. ... .. .. .of the earth. |
| Answer» Solution :Escape VELOCITY. The initial velocity of an OBJECT with which it can escape the EARTH forever is called escape velocity. | |
| 8487. |
A student obtains a blurred image of a distant object on a screen using a convex lens. To obtain a distinct image on the screen he should move the lens |
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Answer» TOWARDS the screen |
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| 8488. |
A ray of light incident at an angle of incidence 48^(@) on a prism of refracting angle 60^(@) suffers minimum deviation. Calculate the angle of minimum deviation. |
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Answer» |
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| 8489. |
What is Avogardo's number ? |
| Answer» Solution :It is the total number of atoms PER mole of the SUBSTANCE. It is equal to `6.023 XX 10^(23)//MOL` | |
| 8490. |
An electric motor converts mechanical energy into electrical energy |
| Answer» SOLUTION :False. Reason : An electric MOTOR CONVERTS electrical ENERGY into mechanical energy | |
| 8492. |
Explain the appplications of convex lenses used in the following instruments. Compound microscope |
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Answer» SOLUTION :Conves lenses are used in the following instruments. Compound MICROSCOPE : A combination of two convex lenses having SHORT FOCAL lengths are used in a compound microscope . It is used to observe bacteria, viruses, cells ,micro-organisms, etc. |
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| 8493. |
What is the effect of conntinuous depletion of ground water along coastal region ? |
| Answer» Solution :It leads to MOVEMENT of SALINE SEA water into freahwater wells then SPOILING their quality. | |
| 8494. |
A bus travelling the first-one-third distance at a speed of 10km/h, the next one-fourth at 20 km/h and the remaining at 40km/h. The average speed of the bus is about |
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Answer» 8km/h |
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| 8495. |
When is the force experienced by a current-carrying conductor placed in a magnetic field (i) maximum, (ii) minimum ? |
| Answer» SOLUTION :(i) maximum when current is at right angles (ii) MINIMUM (zero) when DIRECTION of current is parallel or antiparallel to the direction of magnetic FIELD. | |
| 8496. |
For a particular glass lens f = - 2 m. Only this much data was provided to a student. He was told to calculate the power of lens and to find out type of lens given to him. His answer must be _____ |
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Answer» Power:+ 2 DIOPTRE, Convex LENS |
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| 8497. |
What is meant by vinegar and gasohol? What are their uses ? |
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Answer» Solution :(1) Vinegar is a `5-8%` aqueous solutin of acetic acid. It is USED as PRESERVATIVE in pickles. It is used to COOK meat. It is used as a salad dressing. (2) To increase the efficiency of petrol, it is mixed with `10%` anhydrous ETHANOL, such a FUEL is called gasohol. It is used as a fuel in cars and other vehicles. |
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| 8498. |
What is tidal energy? |
| Answer» Solution :The phenomenon of the high and LOW TIDES PRODUCES a difference in the SEA levels. This is called tidal ENERGY | |
| 8499. |
The important factor that determines the social health of the place you live is ………. |
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Answer» Priority to remove a SHOP in the premises SELLING liquor. |
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| 8500. |
Which effect is illustrated by the observation that when a beam of sunlight enters a dusty room, then its path becomes visible to us. |
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Answer» |
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