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.
| 4351. |
At What distance should an object be placed from a convex lens of focal distance 20 cmso that its four times enlanged image may be obtained.05 |
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Answer» Here m = 4 m = v/u = 4 v = 4u By lens formula 1/v - 1/u = 1/f 1/4u - 1/u = 1/20 (1-4)/4u = 1/20 -3 / 4u = 1/ 20 u = -15 So object should be placed at a distance 15cm from lens |
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| 4352. |
[A plano convex lens has radius of curvature 10 cm. Its focal length is 80 cm in water.Calculate the refractive index of the material of the lens. [Refractive index of water =4] |
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Answer» Given information is,R1=10cm;R2=∞;f=80cmandμwater=43So, Focal length of the plano - convex lens, when it is immersed in water is,1fw=(μrel−1)[1R1−1R2]⇒180=(μmμwater−1)[110−1∞]⇒180=(μm43/−1)[110]⇒18=(3μm4−1)⇒3μm4=98⇒μm=32Therefore, refractive index of the material is1.5 |
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| 4353. |
A combination consisting of a concave lens in contactof a convex lens of focal length 25 cm produces a realimage at a distance of 80 cm when an object is placedat a distance of 40 cm from the combination. Find thefocal length and power of the concave lens.Ans.-4 m,- 0.25 D. |
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| 4354. |
15. A train starts from rest and accelerates uniformlyat a rate of 2 m s2 for 10 s. It then maintains aconstant speed for 200 s. The brakes are thernapplied and the train is uniformly retarded andcomes to rest in 50 s. Find: (i) the maximumvelocity reached, (ii) the retardation in the last50 s, (iii) the total distance travelled, and(iv) the average velocity of the train.Ans. (i) 20 m s-1, (ii) 0.4 m s-2,(iii) 4600 m, (iv) 17-69 m S-l |
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Answer» Train accelerate from start for 10 sso velocity reached at 10s is a×t= 2×10=20m/s1) 20m/s is max velocity as after this the train runs on constant speed2) the train is retarded for 50s from this speed to rest so retardation is velocity /time=20/50=-0.4m/s23) distance travelled is total of distance travelled with accelaration+distance with constant speed+ distance with retardationdistance with acceleration is ut+1/2at2=1/2*2*10*10=100mdistance with constant speed is s×t=20×200=4000mdistance with retardation is ut+1/2at220×50-1/2×.4×50×50=1000-500=500mtotal distance =100+4000+500=4600m4) average velocity= total distance/total time= 4600/260=17.69m/s |
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| 4355. |
2. Passenger in a bus fall back as it accelerates. Why? |
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Answer» When the bus is not moving the passengers are in the state of rest and they have inertia of rest. When the bus starts moving suddenly, the lower part of the body of passengers, which is in contact with the bus, come in motion, but upper part of their body tends to be in the state of rest and the passengers fall backward. pls answer in one word |
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| 4356. |
29. A train travelling at 20 m s-1 accelerates at 0.5 m-2 for 30 s. How far will it travel in this time1110 |
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| 4357. |
soda water, WUUl,a confirm that a colourless liquid given to you i6. How would youpure water?a of the following materials fall in the category of a"pu |
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Answer» A very easy solution is to take a sample of colourless liquid and put on stove if it starts boiling exactly at 100 ºC then it is pure water. Any other colourless liquid such as vinegar always have different boiling point. A very easy solution is to take a sample ofcolourless liquidand put on stove if it starts boiling exactly at 100 ºC then it ispure water. Any othercolourless liquidsuch as vinegar always have different boiling point. |
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| 4358. |
The pressure exerted by a liquid at depth h is given by:(d) hgdg |
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Answer» option b is correct pgh. P=force/area P=mg/area.P=density ×V×g/A. P=density×A×h×g/A.P=density×g×h |
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| 4359. |
A tank is filled with water to a height of 12.5 cm. The apparentdepth of a needle lying at the bottom of the tank is measured by amicroscope to be 9.4 cm. What is the refractive index of water? Ifwater is replaced by a liquid of refractive index 1.63 up to the sameheight, by what distance would the microscope have to be moved tofocus on the needle again? |
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| 4360. |
calculate focal length of the biconvex lens of air if radii of its surface are f0 to 15 cm refractive index of glass 1.5 |
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Answer» 1/f={n-1)(1/R)...from lens maker formula1/f=(1.5-1)(1/15)1/f=0.5/15f=15/0.5=150/5=30cm |
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| 4361. |
The focal length of a concave lens is 2m. Calculate the power of the lens |
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Answer» Focal length = 2m Power = ? so by using , P=1/f v get... P = 1/-2= -0.5 D |
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| 4362. |
15The temperature of 0.5 kg of water is 303 K. It is cooled to278 K by keeping it in a refrigerator. What is the time taken bythe water to reach 278 K if 87.5 J of heat is given out in eachsecond? (the specific heat capacity of water is 4200 J/kg K) |
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| 4363. |
The temperature of 0.5 kg of water is 303 K. It is cooled to278 K by keeping it in a rethe water to reach 278 K if 87.5 J of heat is given out in eachsecond? (the specific heat capacity of water is 4200 J/kg K)frigerator. What is the time taken by |
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| 4364. |
ALTarn5. Figure shows four blocks that are being pulledalong a smooth horizontal surface. The masses ofthe blocks and tension in one string are given.The pulling force Fis:(1) 12 N(3) 40 N(2) 6 N(4) 20 N |
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| 4365. |
Two balls are thrown with same speethe same instant from thg same pointangle of projection à and withhorizontal. If they are simultaneousthe top and bottom of vertical pole.value of iscos αCOS(a) 1(b) 2(c) 3(d) 2 |
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Answer» Could u post the question once again completely, as in some words seem to be missing? |
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| 4366. |
Trebas atert simuliansously towards each otherA and B which are 480 km apart. Thebirat bo taeo 8 hours to travel from A to B whileis sund tokes 12 hours to travel from B to ADetcine when and where the buses will meet. |
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| 4367. |
28.) A balloon has 2 g of air, A small hole is pierced intoofit. The air comes out with a velocity4m/s. If the balloon shrinks completely in 2.5 s.The average force acting on the balloon is(1) 0.008 N(3) 8 N(2) 0.0032 N(4) 3.2 N |
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| 4368. |
5. Convert the following temperature to the Celsius scale:(1)300 K(2)573 K |
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Answer» 0°c= 273know 300k = 300-273= 27° c 2) 573k= 573-273= 300°c |
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| 4369. |
shetl is fired vertically upwards with a velocity vfrom the deck of a ship travelling at a speed of v2. Aperson on the shore observes the motion of the shellas parabola. Its horizontal range is given by2v7%2,,2(3) 2ViV2(4) 2VİVᝠ|
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| 4370. |
9. The resistance between points A andC in the given figur3Ω3Ω3Ω3623Ω |
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Answer» As there is a balance bridgeso middle resistances will be truncatedso there are only 4 resistance of value 3 ohm will be therenow3+3//3+36//6= 6*6/12= 3 ohmanswer |
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| 4371. |
What is the ratio of sini and sinr in terms of velocities in the given figurVelocityVHIVelocity v2 |
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Answer» sini = v1t/ACsinr = v2t/ACthus refractive indexnunu= sini/sinr = v1/v2*Huygens principle: Every point on a wavefront acts as a source of secondary wavelets. The geometric envelope of the waves gives the shape of the wavefront at a later time. |
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| 4372. |
21. Discuss the results when a thermos flask containing tea is vigorously shaken. |
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Answer» Its temperature increases because liquid moves against the viscous forces. Work done againstviscous forces is converted into heat |
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| 4373. |
A thermos flask containing a liquid is shaken vigorously what happens to its temperature? |
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Answer» When liquid is shaken in a thermos flask, work is done on the liquid which gets converted into internal energy of the liquid. Hence, temperature of liquid increases. |
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| 4374. |
0m that thc. tangent |
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| 4375. |
Derive thc relation between Einstein's coefficients. |
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| 4376. |
At what temperature is the root meansquare velocity of gaseous hydrogenmolecules equal to that of oxygen moleculesat 47°C?(A) 20°K(C) -73°K(B) 800K(D) 3°K |
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Answer» option(a) is correct |
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| 4377. |
A 213 (341)2-5 10 |
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Answer» AB=root((3-2)^2+(4-3)^2+(7-4)^2) =root(1+1+9)=root(11)BC=root((-2-3)^2+(-5-4)^2+(10-7)^2) =root(25+81+9)=root(115)3AB+2BC=3root(11)+2root(115) |
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| 4378. |
213 |
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Answer» the square root of the number 45369 is 213 213 is the right answer the square root is 213 |
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| 4379. |
Q2. In Wheatstone's network, the resistances in cyclic order (in series) are P-10 Ω,Q-5 Ω, S-4 Ω and R-4 Ω. For the bridge to, balancea)5 Ω should be connected, in parallel, with, Q .5 Ω10 Ω should be connected in series with Q-5 Ω5 Ω should beconnected in-series with P-10 Ω10 Ω should, connected in parallel with P-10 Ωc) |
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Answer» Given In Wheatstone network the resistance in cyclic order are p=10,Q=5 ,s=4 ,R=4 for the bridge to balance We know that in a balanced Wheatstone bridge or network p/q = r/s 10 / 5 = 4/4 2 = 1 is not balanced so we need to add 5 to q then the circuit will be balanced. So 5 ohm should be connected in series with q for the bridge to be balanced. |
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| 4380. |
Select the cORRECT statement about followingfigure.2.300(1)P + Q will make angle more than 30° with P(2) If PI 10: P Q will make 750 anglewith P(3) If PI IQ then P +Q will make > 15° with P(4) If P I<IQI then P +Q will make <15° with P |
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Answer» option 3 is the correct answer . as , when the magnitude of P will be greater than Q , the resultant will shift towards P.due to more contribution by P in the resultant. |
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| 4381. |
32.Two blocks are connected by a cord passing overa small frictionless pulley and resting on frictionlessplanes as shown in the figure The accleration ofthe blocks is37053° |
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| 4382. |
Two blocks of masses 8kg and 6kg are connected with a string & placed on a roughSurface itself is accelerating up with 2 m/s?. Two forces 60 N each are acting on the two blocks asshown. Friction coefficient for 8kg is 0.5 & that for 6 kg is 0.6. Tension in the string is (g 10 m/s?)honzontal surface60N6ON8kg2m/s0.6 |
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Answer» wrong answer |
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| 4383. |
A force is inclined at 600 to thehorizontal. If its rectangular componentin the horizontal direction is 50 N, themagnitude of the force in the verticaldirection isa) 25 Nb) 75 Nc) 87 Nd) 100 N |
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| 4384. |
49. Two forces, each numericallyequal to 5 N, are acting asshown in the Fig. 6. Then theresultant is(a) 2.5 N5 N(b) 5 N(c) 5/3 N(d) 10 N.60°5 N |
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Answer» upon moving The horizontal 5N force to connect with the tail we get the angle as 180°-60° = 120°angle( __/ ) so, resultant is √5²+5²-2*5*5cos(120) = √5²+5²-5² = √5² = 5N |
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| 4385. |
91. Two forces have magnitudes in the ratio 3:5 and theangle between their directions is 60°. If their resultant is35 N, their magnitudes are |
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| 4386. |
. A Carnot refrigerator works between temperature limitsof 0째C and 27째C. If 10 kg of water at 0째C is convertedinto ice at 0째C, calculate (a) the heat rejected (b) theenergy supplied to the refrigerator. Given : latent heatofice80 kcal kgAns.(a) 879.1 kcal, (b) 3.32 x 105J) |
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Answer» latent heat of ice=80 cal should be use |
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| 4387. |
The magnitude of two forces is in the ratio 3:5 and the angle between their direction is 60.If their resultant force is 35 N then their magnitude will be:a) 12 N.20Nb) 15 N. 25 Nc)18 N, 30 Nd) 21 N, 28 N |
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| 4388. |
e to atmospheric pressure. Take the surface areauman body duhuire (1 aat actingic pressure (1 atm) 1.013 x105 Pa,rea of an average ma1. Find the thrust acting on the hube 1.5mp and atmospheric pressure (1-atduea body whose volume is 2 m3and density 0.52 a/cm35.2 ton wt |
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Answer» we know that pressure = force /area here force is nothing but the thrust exerted so, thrust = pressure x area or F = 1.013 x 10^5* 1.5 thus, thrust will be F = 1.5195 x 10^5N |
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| 4389. |
5.Theresultantoftwoforces, one double the other in magnitude, is perpendicular to the smaller of the twoforces. The angle between the two forces is(a) 60°(b)120°(c) 150(d) 90 |
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| 4390. |
Example 6. Two forces whose magnitudes are in the ratioof 3sgive a resultant of 35 N. If the angle of inclination be60% caleulate the magnitude of each force. (Himachal 04 |
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| 4391. |
LILIULCESTRUTUNULUI LIILISUS21. Three forces of magnitudes 7P. 5P and SP are acting at a particle and maintain equilibrium. Determine theangle between last two forces.angle bell |
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Answer» three forces of magnitude 7 PSP and 80 are acting at a particle and maintaining and barium the last two forces angle is 102 solve do |
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| 4392. |
36, The resultant of two forces 3P and 2P is R. If thefirst force is doubled then the resultant is alsodoubled. The angle between the two forces is(b) 120° (c) 90(a) 60°(d) 180° |
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| 4393. |
) Two forces F1 and F2 of magnitude 5 N each inclinedto each other at 60, act on a body. Find the resultantforce acting on the body. (Ans F = 8. 662N) |
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| 4394. |
I. At what angle two forces (P +Q) and (P-Q) shouldbe inclined so as to have a resultant V (3P2+Q2)? |
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Answer» forces are (P+Q) and (P-Q)Resultant R is (3P^2 +Q^2)^0.5resultant for A,B : R^2 = A^2 +B^2 +2ABcosxR^2=(P+Q)^2 +(P-Q)^2 +2 (P+Q)(P-Q)cosx3P^2 +Q^2 =P^2 +Q^2 +2PQ+P^2 +Q^2-2PQ+2(P-Q)(P+Q)cosx3P^2 +Q^2=2P^2 +2Q^2+2(P-Q)(P+Q)cosxP^2 -Q^2 =(P^2 -Q^2)cosxcosx=1x=0vectors are parallel |
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| 4395. |
Two intersecting vectors of equal magnitude have a resultant of magnitude oneand a half times the magnitude of either vector. What is the angle between thevectors?(82° 49'). |
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Answer» Let R , Q are two vector which magnitude is equal also resultant of it also equal to either e.g | R | = | Q | and resultant = R + Q magnitude of resulatant = | R | = | Q| so, | R | = | R + Q | | R | = √( | R|² + | Q|² +2|R | |Q| cos∅) take square of both sides R² = R² + Q² + 2|R| |Q| cos∅ put | R| =|Q| R² = R² + R² +2R² cos∅ cos∅ = -1/2 ∅ = 2π/3 2¥/3 is the right answer |
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| 4396. |
5)If the resultant of two vectors of equal magnitude is equal tothe magnitude of either vector, then, what is the anglebetween the vectors? |
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Answer» Let R , Q are two vector which magnitude is equal also resultant of it also equal to either e.g | R | = | Q | and resultant = R + Q magnitude of resulatant = | R | = | Q| so, | R | = | R + Q | | R | = √( | R|² + | Q|² +2|R | |Q| cos∅) take square of both sides R² = R² + Q² + 2|R| |Q| cos∅ put | R| =|Q| R² = R² + R² +2R² cos∅ cos∅ = -1/2 ∅ = 2π/3 |
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| 4397. |
Two equal forces are acting at a point with anangle of 60° between them. If the resultantforce is equal to 40 3 N, the magnitude ofeach force is(A) 40 N(C) 80 N[Kerala PMT 2007](B) 20 N(D) 30N |
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Answer» The magnitude of each force is 40 N |
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| 4398. |
6.(1Two forces each numerically equal to 40 dynesare acting as shown in the following figure, thenthe resultant is :-12.40 dyne60°40 dyne(2) 80 dyne(1) 40 dyne(3) 40/3 dyne(4)40V2 dyne |
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Answer» thank you |
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| 4399. |
The magnitude of the resultant of two intersecting forces P and Q is equal to the magnitudeP. Show that the resultant of forces 2P and Q acting at the same angle is perpendicular to Q |
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| 4400. |
8. Electrons with de-Broglie wavelength λ fall on thetarget in an X-ray tube. The cut-off wavelength of theemitted X-rays is:(b) λ -2h(b) no-mem c2 23(d) Ao =A. (JEE 2007) |
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