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This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Pendulum beating seconds at the equator (g = 978 cm//"sec"^2)is taken to Antartica (g = 983 cm//"sec"^2) its length is to be increased by |
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Answer» 0.1 CM |
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| 2. |
The relation between torque and angular acceleration is |
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Answer» `VEC TAU=(I)/( vec PROP)` |
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| 3. |
A metallic sphere of volume 2000cm^(3) contains a cavity of volume 1720cm^(3) inside it. A force of 1960 dyn is required to immerse the sphere completely in water. What is the density of the metal? |
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Answer» |
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| 4. |
A shaft rotating at 3000 rpm is transmitting a power of 3.14 KW. The magnitude of the driving torque is |
| Answer» ANSWER :B | |
| 5. |
The acceleration of a body due to the attraction of the Earth (radius R) at a distance 2R from the surface of the Earth is ......... |
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Answer» `G/9` |
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| 6. |
What force does water exert on the base of a tank of base area 1.5m^(2) when it is filled with water upto a height of 1m (rhoH_(2)o = 10^(3) kg//m^(3).P_(0) = 10^(5)Pa and g=10m//s^(2)) |
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Answer» Solution :Pressure at the bottom of the CONTAINER is P=`P_(0)+hrhog = 10^(5) +1xx10^(3)xx10= 1.1 x 10^(5)PA` Then force DUE to water on the base is`F_("base")=(1.1 xx 10(5)Pa 1.5m^(2))` `=1.65xx10^(5)N` |
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| 7. |
The centripetal force on a satellite orbiting round the earth and the gravitational force of earth acting on the satellite both equal F. The net force on the satellite is |
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Answer» zero |
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| 8. |
A simple pendulum with a negatively charged bob is made to oscillate just above a positively charged plate. What happens to its time period? |
| Answer» Solution :DUE to electrostatic ATTRACTION between the BOB and the plate, the bob feels greater! force in the vertically down ward DIRECTION. This virtually increases g, and hence TIME period decreases. | |
| 9. |
A particle starts from rest .its acceleration a versus time t is as shown in the figure . Find the maximum speed of the particle during its motion (a is in ms^(-2)and t is in seconds) |
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Answer» `(##AKS_ELT_AI_PHY_XI_V01_A_C04_E04_007_A01##)` |
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| 10. |
Canthe magnitude of the resultant of two vectors be less than either of them ? Explain. |
Answer» Solution :In Fig.2.75, `veca=vec(AB) and vecb=vec(BC)`. If the resultant of these two VECTORSIS C , then according to the TRIANGLE LAW of vectors, ` vecc=vec(AC)`. Obviously, the side AC of the triangle ABC may be smaller than AB or BC or both. THUS , the magnitude of the resultant vector `vecc` may be smaller than that of `veca or vecb` , or both . 
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| 11. |
A force F=-K (yhati + xhatj), acts on a particle moving in the x-y plane. Starting from the origin, the particle is taken along the positive x-axis to the point (a,0) and then parallel to the y-axis to the point (a, a). The total work done by the force is |
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Answer» `-2Ka^2` `W_1 = int_0^a vecF .d vecx = int_0^a - K(y hati + x hatj).hati dx` `= int_0^a -K(0 hati + x hatj).hati dx = ` ZERO. And then taking the particle parallel to y-axis to the point (a,a) `W_2 = int_0^a vecF . dvecy = int_0^a - K(y hati + x hatj) .hatj dy` `= int_0^a - K(y hati + a hatj).hatj dy = -Ka int_0^a dy = -Ka^2` Total WORK done, `W = W_1 + W_2 = 0 - Ka^2 = -Ka^2` |
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| 12. |
If a cyclist takes one minute to complete half revolution on a circular path 120 m radius. What is the average velocity ? |
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Answer» 1 m/s |
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| 13. |
The earth is assumed to be a sphere of radius R. A platform is arranged at a height R from the surface of the Earth. The escape velocity of a body from this platform is f v, where v is its escape velocity from the surface of the Earth. The value of f is |
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Answer» `(1)/(SQRT(2))` |
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| 14. |
If the displacement y of a particle is y = A sin (pt + qx), then |
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Answer» <P>the dimensionsof p are `M^(@)L^(@)T` |
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| 15. |
What is meant by end correction in resonance air column apparatus? |
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Answer» SOLUTION :The ANTINODES are not exactly formed at the open end, we have to INCLUDE a correction, called end correction e, by assuming that the antinode is formed at some small distance above the open end. Including this end correction, the FIRST resonance is `(1)/(4) lambda = L_(1) + e` Again taking end correction into account , we have `(3)/(4) lambda = L_2 + e` |
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| 16. |
Banking of roads is the phenomenon of…… outer edge of the road…… the inner edge. |
| Answer» SOLUTION :RAISING , above . | |
| 17. |
Water is maintained at a height of 10 min a tank. Calculate the diameter of orifice needed at the base of the tank to discharge water at the rate of 26.4 m^(3) per minute. |
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| 18. |
What wil happen to potentialenergy of a spring whenit is streched ? |
| Answer» SOLUTION :POTENTIAL energy will INCREASE because workis done on the spring in stretchingit . | |
| 19. |
A double convex lens of refractive index 1.5 has radii of 20cm. Incident rays of light parallel to the axis will come to converge at a distance from the lens is |
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Answer» 20cm |
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| 20. |
A uniform rod AB of mass .m.length 2a. is allowed to fall under gravity with AB in horizontal. When the speed of the rod is .v., suddenly the end .A. is fixed. Find the angular velocity with which it begins to rotate. |
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Answer» Solution :`L_(1)=L_(2)` `MVA=Iomega` `mva=(m(2a)^(2))/(3)omegaimpliesomega=(3V)/(4A)` 
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| 21. |
The moment of the external applied force about a point or axis of rotation is known as |
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Answer» ANGULAR momentum |
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| 22. |
For an object moving with uniform acceleraation, travelling 50m in 5th sec, 70m in 70th sec. (a) Its initial velocity is 5m/s (b) Its acceleration is 20m//s^(2). (c ) Its travels 100m in 9th sec (d) Its average velocity during 9th sec is 90m/s |
| Answer» Answer :B | |
| 23. |
One exametre is equal to |
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Answer» `10^18 m` |
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| 24. |
Discuss the motion of a disc rolling without slipping on a level surface. Hence find the condition for rolling without slipping? |
Answer» Solution :Let us consider a disc that rolls without slipping on a level SURFACE. Let the radius of the ROLLING object be R in one full rotation. The centre of mass is displaced by `2piR`. We would agree that not onoy the centre of mass, but all the points on the disc are displaced by the same `2piR` after one full rotation. The only difference is that the centre of mass takes as straight path, where as, all the other points undergo a path which has COMBINATION of the translational and rotational motion. Especially the point on the edge undergoes a path of a cycloid as shown in the diagram.  As the centre of mass takes only a straigh line path, its velocity `v_(CM)` is only translation velocity `v_("TRANS")(V_(CM)=V_("TRANS"))`.All the other point have two velocities. One is the translational velocity `v_("TRANS")` and the other is rotational velocity `v_("ROT")(V_("ROT")=romega)`. Here r is the distance of the point from the centre of mas and `omega` is the angular velocity. The rotational velocity `v_("ROT")` is perpendicular to the instantaneous position VECTOR from the centre of mass as shown in the figure (a). The resultant of these two velocities is v. This resultant v is perpendicular to the position vector from the point fo contact of the rolling object with the surface on which it is rolling as shown in the figure.  Importance of point of contact: In pure rolling the point of the rolling object that comes in contact with the surface is at momentary rest. This is the case with every point that is one the edge of the rolling object. As the rolling PROCEEDS, all theponts on the edge, one by one come in contact with the surface. the points remain at momentary rest at teh time of contact and then take the path of the cycloid as already mentioned. Hence Let us consider the pure rolling in two different ways. (i) The combination of translational motion and rotational motion about the centre of mass (or) (ii) The momentary rotational motion about the point of contact. As teh point of contact is at momentary rest in pure rolling, its resultant velocity v is zero `(v=0)`. For example in the figure, at the point of contact `v_("TRANS")` is forward ( to right) and `v_("ROT")` is backwards.  Which implis that `v_("TRANS")` and `v_("ROT")` are equal in magnitude and opposite in direction `(v=v_("TRANS")-v_("ROT")=0)`. Hence let us conclude that in poure rolling, for al the points on the edge, the magnitudeof `v_("TRANS")` and `v_("ROT")` are equal `(v_("TRANS")=v_("ROT"))`. As `v_("TRANS")=v_(CM)` and `v_("ROT")=R omega`, in pure rolling we have `v_CM)=R omega` ...........1 The special feature of the equation are 1. in rotational motion, as per the relation `v=r omega`, the centre point will not have any velocity as r is zero. but in rolling motion, it suggests that the centre point has a velocity `v_(CM)` given by equation 1.  At the topmost point, the two velocities, `v_("TRANS")` and `v_("ROT"0` are equal in magnitude and in the same direction (to the right). Thus the resultant velocity v is the sum of these two velocities, `v-v_("TRANS")+v_("ROT")` . In other form `v-2v_(CM)` as shown in the figure. |
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| 25. |
"A carnot engine is called an ideal engine." Why? |
| Answer» SOLUTION :Carnot engine cannot be realised in practice because it is a reversible engine and the conditions to be SATISFIED for this are (i) there should no friction, and no loss of HEAT and (ii) the process MUST be slow. So it is CALLED an ideal engine. | |
| 26. |
STATEMENT-1 The minimum slit separation of a interfernce to produce at least one maximum other than centeral maximum inYDSE"is" 3. STATEMENT2 for amaximum ,path difference = n.The maximum value of path difference =d,silt separation. |
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Answer» STATEMENT -`1`is true statement `2` is true,Statement -`2`is a CORRECT explanation for statement -`1` For`n=1,d=lambda`and we will have THREE maximum. |
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| 27. |
Show that when a string fixed at its two ends vibrates in 1 loop, 2 loops, 3 loops and 4 loops, the frequencies are in the ratio 1 : 2:3: 4. |
Answer» Solution : In case of stationary waves, FREQUENCY in the `n^(th)` mode of vibration is, `f _(n) = (2n)/(2L)` (Where `V = sqrt ((T)/( mu))` = SPEED of transverse wave in stretched string) `therefore f _(n) prop n ` `implies f _(1) :f_(2) :f _(3) :f_(4) = 1:2:3:4` |
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| 28. |
Calculate the work done in blowing a soap bubble slowly of surface tension 4xx10^(-2)Nm^(-1) from a radius of 5 cm to a radius of 10 cm. |
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Answer» |
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| 29. |
Two parallel rail tracks are in north-south direction. Train A moves towards north with a speed of 72 kmh^(-1) and train B moves towards south with a speed of 108 kmh^(-1) What is the (a) velocity of B with respect to A ?, (b) velocity of ground with respect to B ? and (c) velocity of a monkey running on the roof of the train A against its motion (with a velocity of 27 kmh^(-1) with respect to the train A) as observed by a man standing on the ground? |
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Answer» Solution :(a)`-50 ms ^(-1),` (B) VELOCITY of B w.r.t. GROUND `= 30 ms ^(-1),` (c ) Velocity of monkey `= 12.5 ms ^(-1)` |
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| 30. |
If e, E_0, h and C respectively represents electronic change, permittively of free space, planks constant and speed of light then (e^2)/(E_0 hC) has the dimensions of A) angle "" B) relative density C) strain "" D) current |
| Answer» Answer :C | |
| 31. |
The ratio of maximum acceleration to maximum velocity in a simple harmonic motion is 10 s^(-1). At, t = 0 the displacement is 5 m. What is the maximum acceleration ? The initial phase is pi/4 |
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Answer» `500sqrt(2) m//s^(2)` |
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| 32. |
(A): When a person is waling horizontally with a suitcase on his head, no work is done by him against gravitational force (R ): gravitational force on suitcase acts vertically downwards and motion is in horizontal direction, hence dot product becomes zero |
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Answer» Both 'A' and 'R' are TRUE and 'R' is the CORRECT explanation of 'A's |
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| 33. |
The earth is assumed to be a sphere of radius R. A platform is arranged at a height R from the surface of the Earth. The escape velocity of a body from this platform is fv_(e), where v_(e) is its escape velocity from the surface of the earth. The value of f is |
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Answer» `SQRT(2)` |
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| 34. |
Asseration : Corresponding to displacement-time graph of a particle moving in a the body is positive. Reason : Speed of particle is increasing. |
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Answer» If both Assertion and REASON are true and the Reason is CORRECT explanation of the Assertion. THEREFORE, speed of the PARTICLE is increasing. |
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| 35. |
A ball is thrown horizontally and at the same time another ball is dropped down from the top of a tower. Will both the balls reach the ground at the same time? |
| Answer» SOLUTION :YES. It is because the initial vertical velocity of both the BALLS is ZERO and both experiences the same vertical ACCELERATION g. | |
| 36. |
A ball is thrown horizontally and at the same time another ball is dropped down from the top of a tower. Will both strike the ground with the same velocity? |
| Answer» Solution :No. ALTHOUGH their vertical velocities are the same, HORIZONTAL velocities will be different. So their RESULTANT velocities will be different. | |
| 37. |
A 13 m ladder is placed against a smooth vertical wall with its lower end 5 m from the wall. What should be the minimum coefficient of friction between the ladder and the floor so that it remains in equilibrium? |
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Answer» 0.36 |
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| 38. |
Newtone established that a force never occurs singly in natrue Forces always occur in pairs as a result of mutual interaction between to bodies According to Newton s thired law to every action there is always an equal and opposite reaction The force of action and reaction may appear due to actual physical contact of the two bodies or even from a distance The law is applicable whether the bodies are at rest or they are in motion. Read the above passage and answer the following questions (i) It is difficult to walk on sand or ice Why? (ii) What does the law imply in day to day life ? |
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Answer» Solution :(i) On pushing sandy ground th sand SLIPS Therefore force of reaction from sandy ground reduces SIMILARLY friction between our feet and ice is small Thereforc force of reaction from ice is small That is why it is difficult to walk on sand or ice (II) In day to day life this law implies that LOVE begets love if you give love to anydody near or far you get love from hin/her in the equal measure/proportion The same is true for ill feelings They also return to you in the same proportion . |
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| 39. |
Passage-III : If the ends of a rod are rigidly clamped so as to prevent any actual expansion or contraction and then the temperature of the rod is changed, the rod will develop tensile or compressive street or thermal stress. This type of stress sometimes could be adequate to cause permanent strain or also break the rod. To avoid damages for the above said reasons concrete highways are always left with gasps between the section for the expansion or contraction of concrete In a similar way, if the temperature of an object under pressure is increased but the object is not allowed to expand, the pressure will also increase. Assuming a negative sign for a compressive stress and positive sign for tensile stress, answer the following questions Again if we consider a rod rigidly clamped at its ends and its temperature is increased or decrease, the thermal stress in the rod can be expressed as (ANSWER) |
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Answer» MAY be `+ YL ALPHA( Delta T)` |
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| 40. |
Passage-III : If the ends of a rod are rigidly clamped so as to prevent any actual expansion or contraction and then the temperature of the rod is changed, the rod will develop tensile or compressive street or thermal stress. This type of stress sometimes could be adequate to cause permanent strain or also break the rod. To avoid damages for the above said reasons concrete highways are always left with gasps between the section for the expansion or contraction of concrete In a similar way, if the temperature of an object under pressure is increased but the object is not allowed to expand, the pressure will also increase. Assuming a negative sign for a compressive stress and positive sign for tensile stress, answer the following questions Let us now consider an object that is kept under pressure and not allowed to expand on increasingthe temperature (by Delta T: gamma is the coefficient of volume expansion of the material of the solid :alpha is the coefficient of linear expansion of the material of the solid: rho is the density of the material of the solid: B is its Bulk Modulus of Elasticity), then the increase in its pressure will be |
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Answer» `gamma B (DELTA T)` |
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| 41. |
Passage-III : If the ends of a rod are rigidly clamped so as to prevent any actual expansion or contraction and then the temperature of the rod is changed, the rod will develop tensile or compressive stress or thermal stress. This type of stress sometimes could be adequate to cause permanent strain or also break the rod. To avoid damages for the above said reasons concrete highways are always left with gasps between the section for the expansion or contraction of concrete In a similar way, if the temperature of an object under pressure is increased but the object is not allowed to expand, the pressure will also increase. Assuming a negative sign for a compressive stress and positive sign for tensile stress, answer the following questions Consider a rod rigidly clamped at its ends. As the temperature is increased, which of the following statement(s) is/are correct? |
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Answer» The ROD develops a tensile STRESS |
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| 42. |
Figure shows an arragement of four identical rectangular plates A, B, C and D each of area S.Thickness of plates is negligible. Then : |
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Answer» POTENTIAL difference between plates A and B is independent of `Q_(1)` |
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| 43. |
Three vectors satisfy the relation A.B = 0 and A.C =0, then A is parallel to |
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Answer» C |
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| 44. |
A sphere made of rubber of specific gravity rho is released at a depth h inside a liquid of specific gravity sigma(rholtsigma). How much above the surface of the liquid will the sphere jump? Neglect all types of resisting force. |
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Answer» |
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| 45. |
When a horse pulls, a cart , which force helps the horse to move forward? |
| Answer» SOLUTION :The forceexerted by the GROUND on the HORSE. | |
| 46. |
Four particles each of mass 'm' are located at the four corners of a sqaure of side a. If the system is revolving in a circle due to thei mutual force of attraction then the angular velocity and time period of each particle is |
Answer» Solution : From the FIG. `r = a//sqrt(2)` The resultant gravitational force on ONE of the particles `F_(R) = sqrt(2) (Gm^(2))/(a^(2)) + (Gm^(2))/(2a^(2))` This gravitational force provides the NECESSARY CENTRIPETAL force `mr omega^(2) = (Gm)/(a^(2))(sqrt(2)+(1)/(2)) rArr` `(a)/(sqrt(2)) omega^(2) = (Gm)/(a^(2)) ((2sqrt(2)+1)/(2))rArr omega = sqrt((Gm)/(a^(3))(2+(1)/(sqrt(2))))` and `T = (2pi)/(omega) = 2pisqrt((a^(3))/(Gm)((sqrt(2))/(2sqrt(2)+1)))` |
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| 47. |
A stone is dropped from a tower of height 200 m and at the same time another stone is projected vertically up at 50 m/s. The height at which they meet? [g=10m//s^(2)] |
| Answer» ANSWER :C | |
| 48. |
An unruly demonstrator lifts a stone of mass 200 g from the ground and throuws it at his opponent. At the time of projection, the stone is 150 cm above the grond and has a speed of 3.00m/s. Calculate the work doe by the demonstrator during the process. If it takes one second for the demonstrator tolift teh stone and throw, what horsepower does he use? |
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Answer» `v3m/sec, t=1sec` Total work DONE `=1/2mv^2=mgh` `=(1/2)XX(0.2)xx9+(0.2)(9.8)xx(1.5)` `=3.84J` h.p. used `=3.84/749=(5014)xx106-3` |
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| 49. |
In the formula X = 3YZ^2 , X and Z have dimensions of capacitance and magnetic induction respectively . Find the dimensions of Y in MKSQ system. |
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Answer» |
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