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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.
| 1451. |
Find the time taken, by the body projected vertically up with a speed of u, to return back to the ground. |
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Answer» SOLUTION :Let us take the EQUATION `S=ut + 1//2 at^(2)` For ENTIRE motion `S=0`  `a=-g` `u=u` `O=ut -1//2 GT^(2)` `1//2 gt^(2)= ut` `t=2u//g` |
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| 1452. |
A person of mass 55kg pushesh a wall. Work done by this person ………….. |
| Answer» Solution :On PUSHING a WALL, its displacement does not occur. Hence, WORK done by this person would be zero. | |
| 1453. |
In a step down transformer the number of turns in primary coil is greater than that of the number of turns in the secondary coil |
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| 1454. |
For the motion with uniform velocity, how is the distance travelled related to the time ? |
| Answer» SOLUTION : DISTANCE is DIRECTLY PROPORTIONAL to TIME. | |
| 1455. |
Two copper cylinders 'A' and 'B' having their radii in the ratio 1:2 and lengths in the ratio 2:1 are supplied equal amount of heat. Find the ratio of therise in their temperature. |
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Answer» SOLUTION :(i) Heat is absorbed by both the calorimeter and the contents in it. CALCULATE the total heat supplied in the GIVEN time, using Q= (RATE of heat supplied )` xx `time. INITIAL temperature of the calorimeter and the contents in it is the same. Use `Q=mL and Q= msDleta theta` as required. (ii) `61.4^(@)C` |
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| 1456. |
A circle is consturcted of a uniform wire of resistance of 2 ohm per cm and is connected in a circuit such that it offers maximum resistance. (Take redius of the circle as 7 cm). R/l = (2Omega)/(cm) pir^(2) R prop l/a R/l = (l)/(a) |
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Answer» Solution :(i) Find the length of the WIRE forming circle, `l = 2 pir` (ii) The effective resistance of a parallel combination is ALWAYS less than least value of resistancein the combination. (iii) Take such that the valueof resistance of the segment from the circle has maximum possibleresistance. (IV) `(1)/(R_("effective")) = (1)/(R_(1))+ 1/(R_(2))` (v) take `R_(1) = R_(2) = (2 "ohm cm"^(-1)) xx (44 cm)/(2)` (vi) Find `R_(eff)` from (2). (vii) `22 Omega` |
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| 1457. |
All the particles of a shuttle cock execute complicated motion, but its ______ describes the simplest path when it is projected. |
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| 1458. |
Complete the following sentence : The neutral points of a bar magnet kept with its north pole pointing towards geographic north are located ……………………. |
| Answer» Solution :on EITHER SIDE of the magnet in EAST and WEST. | |
| 1459. |
What is viscosity? |
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| 1460. |
How is the resistance of a wire affected if its (a) length is doubled, (b) radius is doubled ? |
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Answer» (B) becomes LESS or one-fourth. |
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| 1461. |
Two girls, each of weight 400 N climb up a rope through a height of 8 m. We name one of the girls A and the other B. Girl A takes 20 s while B takes 50 s to accomplish this task. What is the power expended by each girl? |
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Answer» <P> Solution :(i) POWER expended by girl A :Weight of the girl `mg=400N` DISPLACEMENT (height) `h=8m` Time taken `t=20s` Power `P=("Work done")/("Time taken")` `=(mgh)/(t)` `=(400Nxx8m)/(20s)` `=160W` (ii) Power expended by girl B : Weight of the girl `mg=400N` Displacement (height) `h=8m` Time taken `t=50s` Power `P=(mgh)/(t)` `=(400Nxx8m)/(50s)=64W` Power expended by girl A is 160 W. Power expended by girl B is 64 W. |
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| 1462. |
What amount of work of work in needed in moving 2C Charge through a potential difference of 8V. |
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Answer» Solution :GIVEN : `q = 2 "COULOMB", V = 8 "volt"` `:. "Work" "NEEDED" W = QV = 2 xx 8 = 16 J`. |
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| 1464. |
What is relative density? Explain it mathematically. |
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Answer» SOLUTION :Density of any other substance with RESPECT to the density of water at `4^(@) C`is called RELATIVE density Mathematically, ` R.D. =(" Density of the substance")/("Density of water at " 4^(@) C)` We know that, Density = `"Mass"/"Volume" ` ` :. ` Relative density = `" Mass of the substance / Volume of substance "/"Mass of water / Volume of water" ` Since the volume of substance is EQUAL to volume of water, Relative density = `" Mass of certain volume of substance "/"Mass of equal volume of water" ` Thus, the ratio of mass of a given volume of a substance to the mass of an equal volume of water at `4^(@) C`also denotes relative density |
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| 1465. |
Atwood machine Atwood used the system to prove Netwons laws of motion. Atowood machine consists of two loads of mases m _(1) and m _(2) attached to the ends of a limp of inextensible string as shown in tghe figure 11. The string runs over a pully. FInd the acceleration of each load and tension in the string (m _(1) gt m _(2)) |
Answer» Solution :we know that tension of STRING always tries to pull te bodies up.  From the FBD of the MASS `m _(1),` there exist TWO forces on the LOAD of mass `m _(1),` one is tension of the string acting in upward direction and weight of the load `(m_(1) g)` acting in downward direction. The net force on `m _(1) F _(n et) = m_(1) a` `implies m_(1) g -T =m_(1) a ---------------(1)` Thus the net force `(F_(n et))` acting on mass `m _(1)` produces an acceleration .a. in it. When `m _(1)` MOVES down, `m _(2)` moves up. So the magnitudes of acceleration are same.  From the FBD of mass `m _(2)` `F _(n et) =T - m _(2) g =m_(2)a ----------------(2)` Solving (1) and (2) equations, we get `a = ((m _(1) - m _(2) g)/( m _(1) + m _(2))` ` T = ( 2m _(1) m _(2) g)/( m _(1) +m_(2))` |
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| 1466. |
Observe the figures of an object placed in different liquids Compare the gravitational force and the buoyancy acting on the body when it is in liquids A and B. . |
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| 1467. |
A box is pushed through a distance of 4m across a floor offering 100N resistance. How much work is done by the resisting force ? |
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Answer» Solution :The force of FRICTION acting on the box, F = 100 N The DISPLACEMENT of the box, S = 4m The force and displacement are inoppositedirections. HENCE work done on the box is negative. That is, `W = -FS` ` = -100 xx4` ` = -400` J |
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| 1468. |
Radiaoactivity is__________by the chemical and physical states of the material. |
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| 1469. |
A force of 5 N is acting on an object. The object is displaced through 2m in the direction of the force, if the forec acts all through the displacement, find the work done by the force. |
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| 1470. |
Which of the following is the speed of sound in copper and which in aluminium? (a) 5100 m//s (b) 1500m//s (c) 3750 m//s |
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| 1471. |
A variable immersion hydrometer is used to measure the specific gravity of two liquidsWhen the hydrometer reads 0.8, half of the total length of the hydrometer stem is immersed in the liquid and when the hydrometer reads 0.6,3//4 th of the total length of the hydrometer stem is immersed in the liquid. What is the maximum and minimum reading that can be measured by using this hydrometer ? |
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Answer» Solution :(i) `(v+(la)/(2))d=w` (1) `(v+(3la)/(4))d=w` (2) EQUATE (1) and (2) to find a relation between v and la. SUBSTITUTE the VALUE of la in equation to determine 'w' in TERMS of 'v'. When the hydrometer reads minimum (ii) `d_(1)=w` (3) When the hydrometer reads maximum (v+la) `d_(2)=w`(4) Substitute the value of 'w' in (3) and (4) to setermine `d_(1)andd_(2)`. |
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| 1472. |
The angle of deviation of light ray in a prism depends on the angle of …............. . |
| Answer» SOLUTION :PRISM and ANGLE of INCIDENT | |
| 1473. |
What happens to the buyoant force as more and more volume of a solid object is immersed in a liquid ? When does the buoyant force becomes maximum ? |
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| 1474. |
Calculate the apparent weight of wood floating on water if it weighs 100g in air. |
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Answer» Solution :APPARENT weight weight of the BODY-Weight of LIQUID Since the body is FLOATING the two are equal. So, apparent weight is zero. `100 - 100 = 0` |
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| 1476. |
What is meant by momentum ? |
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| 1477. |
Find thearea of cross-sectionof a rodthe diameterof whichismeasuredwith ascrewgaugewithreadings as shown in thefigure |
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Answer» Solution :`(i) d_(1) =(1//2) ` of a metre =distanceof 2 kgfrom thesupport (II) `d_(2) (1//4)` OFA metre (iii) Find `W_(2)` USING thetheoremof momentsi.e., `w_(1)d_(1)= w_(2)d_(2)` (iv) Mass =4 kg |
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| 1478. |
Define heat capacity (or) thermal capacity ? |
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Answer» Solution :Heat capacity or thermal capacity is defined as the amount of heat energy REQUIRED to raisethe TEMPERATURE of a body by `1^@C` . It is denoted by C. C=Q/t, where C. is the heat capacity. .Q. is the quantity of heat required and .t. is rise in temperature SI unit of heat capacityis J/K. It is also expressed in `cal//^@C , kcal//^@C` or `J^@//C`. |
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| 1479. |
The figure shows a jar containing honey and kerosene Suggest a method to reduce the viscosity of a liquid |
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| 1480. |
When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remains the same. Do you hear echo sound on a hotter day ? |
| Answer» Solution :Yes . The molecular distance is more FREQUENTLY carries THEENERGY DUE to HIGH temperature. | |
| 1481. |
Choose the correct word/words to complete the following sentence : When sound travels in a medium ...... (the particles of the medium, the source, the disturbance, the medium) travels in form of a wave. |
| Answer» SOLUTION :the DISTURBANCE | |
| 1482. |
Force involved in uniform circular motion is given by ______ |
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Answer» `F=(mv^2)/R` |
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| 1483. |
Explain how does SONAR work? |
| Answer» Solution :SONAR STANDS for Sound Navigation And Ranging. Sonar is a device that uses ultrasonic WAVES to MEASURE the distance, direction and speed of underwater objects. Sonar consists of a transmitter and a DETECTOR and is installed at the bottom of boats and ships. The transmitter produces and transmits ultrasonic waves. These waves travel through water and after striking the object on the seabed, get REFLECTED back and are sensed by the detector. The detector converts the ultrasonic waves into electrical signals which are appropriately interpreted. The distance of the object that reflected the sound wave can be calculated by knowing the speed of sound in water and the time interval between transmission and reception of the ultrasound. Sonar technique is used to determine the depth of the sea and to locate underwater hills, valleys, submarine, icebergs etc. | |
| 1484. |
What is relative density ? |
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Answer» SOLUTION :The RELATIVE DENSITY of a SUBSTANCE is the ratio-of its density to that of WATER `"Relative density"=("Density of a substance")/("Density of water")` |
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| 1485. |
Are the action and reaction equal and opposite ? |
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| 1487. |
It takes 5 years for light to reach the earth from a star. Express the distance of star from the earth in (i) light year, (ii) km . Take speed of light = 3xx10^8 m s^(-1) and1 year = 3.153 xx 10^7 s |
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Answer» Solution :The distance travelled by LIGHT in 1 YEAR is called 1 light year. Thus the distance travelled by light in 5 years = 5 light year. `THEREFORE` Distance of star from the earth = 5 light year. (ii) 1 light year = speed of light `xx` TIME `1 ` year `=(3xx 10^8 m s^(-1)) xx (3.153xx10^(12)s)` `= (9.46xx10^(15) m = 9.46xx10^(12) km ` `therefore ` Distance of star from the earth `= 5 xx 9.46 xx 10^(12)` km `= 4.73xx10^(13) km ` |
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| 1488. |
A train first travels for 30 min with a velocity 30 km h^(-1) and then for 40 min with a velocity 40 km h^(-1) in the same direction, Calculate : (i) the total distance travelled, (ii) the average velocity of the train. |
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Answer» Solution :Given `t_(1) =30` min `=(1)/(2) h ,v_(1) = 30 "Km h"^(-1)` `ta_(2)` =40 min `= (2)/(3) h ,v_(2)`= 40 km `h^(-1)` . (i) DISTANCE travelled = velocity `xx` time `:. S_(1) = v_(1) xxt_(1) = 30 xx(1)/(2) = 15 ` km `S_(2) = v_(2) xxt_(2) = 40 xx(2)/(3) = (80)/(3)` km Total distance travelled `S= S_(1) + S_(2)` `= 15 + (80)/(3) = (125)/(3) `km = 41.67 km (ii) Total time of JOURNEY `t=t_(1) +t_(2)` `= (1)/(2) +(2)/(3) = (7)/(6) h` `:.` Average velocity = `("Total distance travelled S")/("Total time of journey t")` `= (41.67 km)/((7//6)h)= 35.71 km h^(-1).` |
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| 1491. |
Draw a labelled diagram to make an electro magnet from a soft iron bar AB. Mark the polarity at its ends. What precaution would you observe ? |
Answer» Solution :The labelled DIAGRAM is SHOWN in FIG. 10.17. The polarity at the end A where the current is clockwise, is south (S), while at the end B where the current is anticlockwise, is north (N). 
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| 1492. |
What are the various energy trans-formations that occur whenyou are riding a bicyle? |
| Answer» Solution :We use our MUSCULAR ENERGY in RIDING a bicycle. Our muscular energy is TRANSFORMED into kinetic energy. Some muscular energy is used in doing work against the friction from the ROAD. This part of muscular energy is transformed into heat energy. | |
| 1493. |
What is the effective density of the maxture of water and milk when (i) they are taken with same masses (ii) they are taken with same volumes |
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Answer» Solution :Let US say the DENSITIES of water and milk are `rho_(1) and RHO _(2)` (i) When they are taken with same mass .m. and their VOLUMES are `V_(1) and V_(2),` the mass of water `m = rho _(1) V_(1) , V_(1) =(m)/(rho_(1))` and the mass of milk `m = rho_(2) V_(2), V_(2) = (m)/( rho _(2))` Total mass of water and milk is `m + m 2m` Total volume of the water and milk is `V _(1) + V _(2) = (m)/( rho _(1)) + (m)/( rho _(2))` `= m ((1)/( rho_(1)) + (1)/( rho _(2 )))` ` = (m ( rho _(1) + rho _(2)))/(rho _(1) rho _(2))` The effective density of the mixture `(rho _(eff))=` Total mass /Total volume `= (2m)/( m (rho _(1) + rho _(2)) // rho _(1) rho _(2))` `= ( 2)/(( rho _(1)+ rho _(2)) // rho_(1) rho _(2))` ` = (2 rho _(1) rho_(2))/( rho_(1) + rho _(2))` (ii) when they are taken with same volume .V. and their masses are `m _(1) and m _(2)` the volume of water `V = m _(1) // rho _(1)` That is `m _(1) = V rho _(1)` and the volume of milk `V = m _(2) // rho _(2)` Total mass of water and milk is `m _(1) + m _(2) = V rho _(1) + V rho _(2)` `=V (rho _(1) + rho _(2))` Total volume of water and milk is `V +V =2V` The effective density of the mixture `(rho _(eff))=`Total mass/Total volume `rho _(eff) =(V (rho _(1) + rho _(2))/( 2V)` `= 1/2 (rho _(1) + rho _(2))` |
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| 1494. |
A solid of densit 5000 kgm^(-3) weights 0.5 kgf in air. It is completely immersed in water of density 1000kgm^(-3). Calculate the apparent weight of the solid in water. |
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| 1495. |
A body of weight 800 N sinks in a liquid. The weightof the liquid displaced is 200 N What is the buoyant force? |
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| 1496. |
The frequency of source of sound is 100 Hz. How many times does it vibrate in a minute ? |
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Answer» This means the source of SOUND VIBRATES 100 times in one sound. Therefoundnumber of vibrations in 1 minute i.e., in 60 second `=100xx60=6000` times. |
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| 1498. |
The volume of a solid of mass 500 g is 350 cm^(3). What will be the density of this solid ? |
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Answer» SOLUTION :Density of solid `=("Mass of solid ")/("VOLUME of solid" )` `=(500g )/(350 CM^(3))` `=1.42 g//cm^(3)` |
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| 1499. |
A ball is falling freely from the height 10 m. On striking the ground its energy decreases 40 %, then how high can it jump? |
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Answer» `=mxx10xx10` `=(100M)J` On STRIKING the earth its energy decreases 40 %. So REMAINING energy with the ball = `60% (100m)J` `=(60)/(100)xx(100m)J` `=(60M)J` Suppose, after striking the ball on the ground, it can jump at height up to h., then `60m=mxxgxxh.` `therefore 60=10xxh.` `therefore h.=6m` |
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| 1500. |
What is inertia of motion ? |
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