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.
| 351. |
An object P is moving with a constant velocity for 5 minutes . Another object Q is moving with changing velocity for 5 minutes . Out of these two objects which one has acceleration? Explain. |
|
Answer» we know acceleration is the change in velocity with time therefore, from this statement we can say that object p has no velocity because it is not changing its velocity with time , it is moving with a constant velocity , therefore it's acceleration will be 0 but we can say that object q has acceleration because it is said to changing the velocity with time as written in the questions |
|
| 352. |
A string of length L is fixed at orfe end and carriesa mass M at the other end. The string makes 2/πrevolutions per second around the vertical axisthrough the fixed end as shown in the figure above,then tension in the string is(1) ML(3) 4 ML(2) 2 ML(4) 16 ML |
| Answer» | |
| 353. |
A string of length 1 m is fixed at one end and car-ries a mass 100 g at other end. The string makes2revolutions per second around a vertical axispassing through its second end. Find the tension inthe string. |
|
Answer» w = 2pi*2/pi = 4 rad/s. npw consider angle thethaa wth vertical and do comonents of Tension along horizontal and vertial and balnce them with mg and mw^2r where from geomtery r = lsinthetha. after balancing the eqns would be: T = mw^2l T = 100/1000 * 16 * 1 = 1.6 N in vertical direcn. Tcosthetha = mg cosththa = 5/18 or thetha = arccos(5/18) |
|
| 354. |
10. A particle is rotated in a vertical circle by connecting itto a string of length I and keeping the other end of thestring fixed. The minimum speed of the particle whenthe string is horizontal for which the particle willcomplete the circle is(a) vgl(b) v2gl (c) 3gl (d) v5glt, |
| Answer» | |
| 355. |
masses Mi and M2 are connected at the two ends of a light string that passes over a lightfrictionless fixed pully. Find the acceleration of the masses and the tension in the string.cornecting them when the masses are releaseds |
| Answer» | |
| 356. |
Miand M2 are connected at the two ends of a light string that passes over aTwo massesorcotrtal GfrectioD.lightstringnless fixed pully. Find the acceleration of the masses and the tension in theconnecting them when the masses are released |
| Answer» | |
| 357. |
1. Three equal weights A, B and Cof mass 2 kg each are hanging on a string passing overa fixed frictionless pulley as shown in the figure. The tension in the string connectingweights B and Cis approximately(a) zero13 N(c) 3.3 NABI(d) 19.6 N |
|
Answer» Let the required tension be T and the tension in the string connecting A and B be T1 equations are: for C = 2 g - T = 2 a (i) for B = 2 g + T - T1= 2 a (ii) and T1- 2 g = 2 a (iii) adding (i), (ii), (iii) 2 g = 6 a or a = g/3 substituting in (i) = T = 2(g -a) = 2(g - g/3) = 4 g/3 = 4(9.81)/3 = 13.08 N |
|
| 358. |
() suyash bought 24 kg of sugar and Ashish bought 31 kg. How much sugar2they buy altogether ? If sugar costs 32 rupees per kg, how much did they spenaon the sugar they bought ? |
| Answer» | |
| 359. |
How many packets of kg sugarcan be made from 3 kg of sugar?164 |
| Answer» | |
| 360. |
[NCERT)Three equal charges 2.0 x 10°C each, are heldfixed at the three corners of an equilateraltriangle of side 5 cm. Find the coulomb forceexperienced by one of the charges due to the 11. |
| Answer» | |
| 361. |
16. Three equal charges, 2.0 x 10-C each, are held fixedat the three corners of an equilateral triangle of side5 cm. Find the Coulomb force experienced by one of thecharges due to the rest two. |
| Answer» | |
| 362. |
A charge q is placed at the centre of the line joining twoequal charges Q. The system of the three charges wil be inequilibrium. if q is equal to |
|
Answer» Let two equal charges Q placed at point A and B joining line segment. Let length of line segment is x and charge q is placed at centre. Then distance of charge q from point A and B is x/2 Force on the charge at B due to the charge at A is, F1 = kQ2^2 /x^2 Force on the charge at B due to the charge q is, F2 = kQq/(x/2)^2 For the system to be in equilibrium, F1 + F2 = 0 => kQ^2/x^2 + kQq/(x/2)^2 = 0 => q = -Q/4 |
|
| 363. |
A charge q is placed at the centre of the linejoining two equal charges Q each. Thesystem of the three charges will be inequilibrium, if q is equal toO-0/2O +Q/2 |
| Answer» | |
| 364. |
Six charges, three positive and three negative of equalmagnitude, are to be placed atthe vertices ofa regular hexagonsuch that the electric field at Ois double the electric field whenonly one positive charge of samemagnitude is placed at R. Whichof the following arrangements ofcharges is possible for P. eRS, Tand U respectively ?[IIT 2004] |
|
Answer» Option D |
|
| 365. |
4. Three positive charges of equal value are placedat the vertices of an equilateral triangle. The resultinglines of force should be sketched as in(b)(c)(d) |
|
Answer» c is the best answer answer of the question is C |
|
| 366. |
15.Three point-charges q1, 92, 93 are in line at equaldistances. q2 and q3 are opposite in sign. Find themagnitude and sign of q1, if the net force on g3 is zero.Ans. q1 has a magnitude four times |
|
Answer» Let Q1 be a test positive charge, since charges of Q2 and Q3 are opposite in sign, there exists an attractive force between them. One point to be kept in mind here is that the net force on Q3 must be 0 as given in the problem. In order to keep force on Q3 be 0, the force between Q1 and Q3 must be force of repulsion as we already have attractive force between Q2 and Q3Now to satisfy the equilibrium position, the two forces must balance each other.KQ1Q3/4R2 = -KQ2Q3/R2….. (distance between Q1 and Q3 is 2R).Q1 = -4Q2Hence charge of Q1 is opposite to that of Q2 and same as that of Q3 hit like if you find it useful |
|
| 367. |
e 1.a Consider three charges geach equal to g tvertices of an equllateral triangle of side L What is th focharge Q twith the same sign as ) placed at the cetriangle. as shem in F's. 1.97onathea.-qFIGURE 1.9 |
|
Answer» Using symmetry here we see that that all froces =) F1 = F2 = F3 = kQq/r^2 here r = AO = BO = CO using trigonometry we can find " r " Here we can see that length of each side of ∆ ABC is " L " =) In ∆ BOD Angle OBD = 30° and BD = L/2 COS 30 ° = L/2r =) r = L/2 × sec30° =). r = L/2 × 2/√3 = ( 1/√3 ) L -----(1) so we can see tha all forces are equal F1 = F2 = F3 = kQq/ (L/√3)^2 = 3kQq/L^2 and angle between each forces is 120° using Lami's theorem if all forces are equal in magnitude and angle between then is also equal and planar then resultant force is 0 =) Fnet = F1 +F2 + F3 = 0 =) here we add forces using vectors to get net force = 0 so Net force on charge " Q " placed at centroid is zero. not satisfactry |
|
| 368. |
Example 5 A sphere of mass 40 kg is attracted by a second sphere of mass 60 kg with a forceequal to 4 mgf. If G = 6 × 10-11 Nm2 kg 2, calculate the distance between them. Acceleration due togravity 10 ms-2. |
| Answer» | |
| 369. |
20, A monkey of mass 20 kg is holding a vertical rope. Therope will not break when a mass of 25 kg is suspendedfrom it but will break if the mass exceeds 25 kg. What isthe maximum acceleration with which the monkey canclimb up along the rope (g 10 m/s2)(1) 10 m/s2(3) 2.5 m/s2(2) 25 m/s2(4) 5 m/s |
| Answer» | |
| 370. |
A body of mass mi ( 12 kg) is placed ona smooth horizontal table shown in figure.It is connected to a string which passes overa frictionless pulley and carries anotherbody of mass m2 (8 kg) at the other end.Calculate the acceleration produced in thebodies when the nail fixed on the table isremoved. (Take acceleration due to gravityg 10 m s2) |
|
Answer» net force acting on the system is m2*g = 8*10 = 80 and total mass of the system is (8+12) = 20kg so, acceleration of the system = 80/20 = 4m/s² |
|
| 371. |
(3) g- a,g(4) a.g20, A monkey of mass 20 kg is holding a vertical rope. Therope will not break when a mass of 25 kg is suspendedfrom it but will break if the mass exceeds 25 kg. What isthe maximum acceleration with which the monkey canclimb up along the rope (g 10 m/s2)(1) 10 m/s2(3) 2.5 m/s2(2) 25 m/s2(4) 5 m/s2 |
| Answer» | |
| 372. |
A body of mass mi ( 12 kg) is placed ona smooth horizontal table shown in figure.It is connected to a string which passes overa frictionless pulley and carries anotherbody of mass m2 ( 8 kg) at the other end.Calculate the acceleration produced in thebodies when the nail fixed on the table isremoved. (Take acceleration due to gravityg 10 m s2)nl1m2 |
|
Answer» net force acting on the system is m2*g = 8*10 = 80 and total mass of the system is (8+12) = 20kg so, acceleration of the system = 80/20 = 4m/s² |
|
| 373. |
An object is placed infront of a convex mirror at a distance of 50 cm. Aplane mirror is introduced between object and concave mirror coveringlower half of the concave mirror. If the distance between object and planemirror is 30 cm, both images coincide. Then what is the focal length of theconvex mirror. |
|
Answer» the focal length of the convex mirror is 80 |
|
| 374. |
3. What is the Hatune O(a) + 4, and (b) -2?4. State the relation between object distance, image distance and focal length of a spherical mirror (concavemirror or convex mirror).ing nf each symbol which occurs in it. |
|
Answer» thank u |
|
| 375. |
The image formed by a convex mirror of focal length 20cm is at adistance of 50cm. What is the distance of the object from thmirror? |
| Answer» | |
| 376. |
The image formed by a concave mirror is real, inverted and of same size asthat of the object the position of the object is: |
| Answer» | |
| 377. |
If a charged spherical conductor of radius 10cm haspotential V at a point distant 5 cm from its centre, then thepotential at a point distant 15 cm from the centre will be |
|
Answer» Potential at any point inside the conductor will be same as surfaceSo V =K /rWhere k is constant and r is the distance from centreSo V =k/ 10K =10VVat r=15=k/15=10V/15=2/3V |
|
| 378. |
uur biue why?11. A person is known to use a lens of power(i)-5.5 D for his distant vision(ii) +1.5 D for his near visionCalculate the focal length of the lens used for correcting his(a) Distant vision and (b) Near vision problems. |
| Answer» | |
| 379. |
A person needs a lens of power -5.5 dioptres forcorrectinghisdistantvision.ifor vision?naturerrecting his near vision he needs a lens of power +1.5 dioptre. What is thelength of the lens required for correcting (ü) distant vision, and (ij near vision?The far point of a myopic person is 80 cm in front of the eye. What is thepower of the lens required to correct the proble |
| Answer» | |
| 380. |
7. As a distant object moves towards a convex lens, how does the size, nature of image change? |
|
Answer» As the object moves towards the focus of the lens the size of the image increases and it moves away from the focus. ... When the object is at a distance less than the focal length, the image formed is virtual, enlarged and erect. It is formed on the same side of the lens as that of the object. |
|
| 381. |
(Real image formed by concave mirror is twiceof size of an object. If focal length of mirroris 15 cm, Then object distance from mirrorwill be.) |
| Answer» | |
| 382. |
At which position will you keep an object in front of a convexlens so as to get a real image of the same size as the object |
|
Answer» To get a real image of same size , the object should placed at a distance 2f from the optical center in the front of the lens |
|
| 383. |
5. Where should an object be placed from a converging lens of focal length 15 cm, so asto obtain a real image of same size as that of object? |
|
Answer» The object should be placed between 15cm and 30 cm( Between f and 2f) from the converging lens to obtain a real and magnified image. |
|
| 384. |
Differentiate between:-(a) Real and virtual image.(b) Convex and Concave lens |
|
Answer» a) b) hit like if you find it useful |
|
| 385. |
real image and virtual image |
|
Answer» The following are the differences between a real image and virtual image: A real image is formed when the rays of light after reflection or refraction actually meet at some point. A virtual image is formed when the rays of light after reflection or refraction appear to meet at a point. |
|
| 386. |
The image of an extended object, placedperpendicular to the principal axis of amirror, will be erect if(A) The object and the image areboth real(B) The object and the image areboth virtual(C) The object is real but the imageis virtual(D) The image is diminished andobject is real |
|
Answer» answer of is question is c d |
|
| 387. |
57. A convex lens produces a double size real image whenan object is placed at a distance of 18 cm from it. Whereshould the object be placed to produce a triple size realimage? |
| Answer» | |
| 388. |
4, What is meant by magnification?Write its expression. What is its signfor thea) real imageb) virtual image |
|
Answer» Magnification:-~~~~~~~~~~~~~~☆Magnification produced by a spherical mirror or lens can be defined as the ratio of the height of the image to that of the object. ☆If we take h as the height of the object and h' as the height of the image, then the Magnification produced by the mirror or lens will be:- Magnification, m = h'/h ☆The sign of the Magnification for real image is taken to be as (-)ve and it is taken as (+)ve for virtual images. |
|
| 389. |
Time to AnswerWrite True or False.(a) A real image is always inverted and can be obtained on a screen.(b) A virtual image is always erect and cannot be obtained on a screen.(c) Light travels in a circular path.(d) Reflection from a rough surface is diffused or irregular.(e) Reflection from a smooth surface is regular.(f) A plane mirror forms a real image. |
|
Answer» true all answer. TrueTrueFalseTrueTrueFalse |
|
| 390. |
A concave mirror produces three times magnified (enlarged) real imageof an object placed at 10 cm in front of it. Where is the image locatedr |
| Answer» | |
| 391. |
A concave mirror produces three times magnified (enlarged) real imageof an object placed at 10 cm in front of it Where is the image locater? |
|
Answer» Given, magnification (m) = -3 (image is real)object-distance (u) = -10 cmimage-distance (v) = ?Now, In a mirror m= -v/u = -3 = -v/-10 -3 x 10 = v v = -30 cmSo, the object is placed 30 cm in front of the mirror. |
|
| 392. |
A concave mirror produces three times magnified (enlarged) real imageof an object placed at 10 cm in front of it. Where is the image located?2. |
| Answer» | |
| 393. |
pupi1sTheWe feel strain in our eyes if we watch television or read a book fromclose distance.a veryоо |
|
Answer» Visual tasks such as reading, spending hours at the computer or watching television require you to focus and concentrate – and without you realizing it, you are actually placing strain on your eye muscles. Theeye muscles tightenand cause your eyes to become dry, irritated and uncomfortable.. |
|
| 394. |
What is the difference between noise and music? |
|
Answer» Musicissounds organized in time. By the way, with regard to the physics ofsound. Noise refers to individualsoundsthat do not have a regular oscillating waveform and they have no recognizable pitch. All the time the noise is above 65db but music (without home theater) is below the 65db. music is bearable noise is unbearable |
|
| 395. |
19/ An object 5 cm in length is held 25 cm away from a converging lens of focal le10 cm. Draw the ray diagram and find the position, size and the natureimage formed. |
| Answer» | |
| 396. |
On your observation of daily activities give two examples of objects each in which either potentialor kinetic energy exist.5. |
|
Answer» moving bike possess kinetic energy. while climbing the stairs, we store potential energy Table fan, electric fan, |
|
| 397. |
5. A ball is placed near the periphery of a merry-go-round and is tied to its centreMerry-go-round is rotating about an axis passing through its centre. [4 M](i) What will be your observation when you are standing outside the merry-9o-round? Explain it.(ii) What will be your observation when you are standing at the centre of themerry-go-round? Explain it |
| Answer» | |
| 398. |
J200 J.Example 4 A bag of wheat weighs 100 kg. Towhat height should it be raised so that its potentialenergy may be 9800 J? Take g = 9.8 ms-2. |
| Answer» | |
| 399. |
A lift weighing 100 kg is falling freely undergravity what will be the weight of a man of100 kg standing on its base ? (g = 10 m/s2) |
|
Answer» 100/10 m/s^2=10 m/s^ 10 is the correct answer of the given question |
|
| 400. |
2 Consider the circuit shown below4225 2w100 Vis000000the ideal source supplies 1000w, half of which is delivered to the 100 load, then the valueFb is-)1.5(B).89(C).56(D).67 |
| Answer» | |