Saved Bookmarks
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. |
The mean density of seawater is p. The bulk modulus is K. Find the change in density of seawater in going from the surface of water to a depth h. |
|
Answer» <P> Solution :`m=vrho, o rho DV+v drho RARR rho.dv=-v.drho``(dv)/(v)-(drho)/(rho) rArr =(-P)/((dv)/(v)) rArr K=(-(h rho g))/(-(drho)/(rho)) rArr K=(rho p^(2)g)/(d rho), d rho=(rho^(2)GH)/(K)` |
|
| 2. |
Four identical particles each of mass m are arranged at the corners of a square of sie a. If mass of one of th particle is doubled, the shift in the centre of mass of the system is |
|
Answer» `(a)/(2sqrt(2))` |
|
| 3. |
An intense stream of water of cross-sectional area A strikes a wall at an angle theta with the normal to the wall returns back elastically. If the density of water is rho and its velocity is v, then the force exerted in the wall will be |
|
Answer» `2 A V^(2) rho COS theta` |
|
| 4. |
A pendulum clock keeping correct time its taken to high altitude |
|
Answer» it will KEEP corrct TIME |
|
| 5. |
A boat wassteeredover a flowing river in such a way that it reached the opposite bank following the shortest path. Time requiredin this case was double the time the boat would have taken to cross the river if therewas no river current. If the velocity of the boat was 2 m *s^(-1), what was the velocity of the current? |
|
Answer» |
|
| 6. |
Assertion : Time period of revolution of a polar satellite of earth is 100 minutes. Reason : Polar satellites are Sun-synchronous satellites. |
|
Answer» If both ASSERTION and reason are CORRECT and reason is a correct EXPLANATION of the assertion. |
|
| 7. |
A longitudinal wave is travelling at speed u in positive x direction in a medium having average density r0. The displacement (s) for particles of the medium versus their position (x) has been shown in the figure. Answer following questions for 0 lt x le 10 cm (a) Write x co-ordinates of all positions where the particles of the medium have maximum negative acceleration. What is density at these locations – higher than rho_(0), less than rho_(0) or equal to r_(0)? (b) Write x co-ordinates of all locations where the particles of the medium have negative maximum velocity. What do you think about density at these positions? (c) Knowing that the change in density (Delta rho) is proportional to negative of the slope of s versus x graph, prove that (d rho)/(dx) prop -a where a is accelerationof the particles at position x. At which point (0 lt x le 10) is (d rho)/(dx) positive maximum. |
|
Answer» (B) `x=2, x=10; DELTA rho` is maximum negative (C) `x=4` |
|
| 8. |
An object is weighed at the North Pole by a beam balance and a spring balance, giving readings of W_B and W_Srespectively. It is again weighed in the same manner at the equator, giving reading of W_(B) and W_(S)respectively. Assume that the acceleration due to gravity is the same everywhere and that the balances are quite sensitive a) W_(B) =W_(s) b) W_(B). =W_(s). c) W_(B) = W_(B).d) W_(s). lt W_S |
|
Answer» only a & B are TRUE |
|
| 9. |
An ideal gas is trapped between mercury thread of 12cm and the closed lower end of a narrow vertical tube of uniform cross section. Length of the air column is 20.5 cm, when the open end is kept upward. If the tube is - making 30° with the horizontal then the length of the air column is (assuming temperature to be constant and atmospheric pressure = 76cm of Hg) |
|
Answer» 22 cm |
|
| 10. |
If a vessel containing a fluid of density rho upto height h is accelerated vertically downwards with acceleration a_(@) then the pressure by fluid at the bottom of vessel is: |
|
Answer» `P=P_(@)+RHO gh+rho ha_(@)` |
|
| 11. |
Assuming Earth to be a sphere of a uniform density, what is value of gravitational acceleration in mine 100 km below the Earth surface = ………. "ms"^(-2) |
|
Answer» `9.66` |
|
| 12. |
Assertion:When a satellite is moving in a circular orbit around the Earth, total energy of a satellite, is half of its potential energy.Reason:The gravitational force obeys the inverse square law of distance.Select the correct statement of the following. |
|
Answer» Assertion and reason are true and reason explains assertions correctly. POTENTIAL energy `P.E=(GMm)/(r)` `thereforeT.E=(1)/(2)P.E` Reason:Gravitational force F is inversely proportional to the square of distance. |
|
| 13. |
A particle is dropped from the top a tower h metre high and at the same moment another particle is projected upward from the bottom. They meet the upper one has descended a distance h//n . Show that thevelocities of the two when they meet are in the ratio 2: (n-2) and that the initial velocity of the particle projected upis sqrt((1//2))n gh. |
|
Answer» `rArr u=(h)/(t) =sqrt((nhg)/(2))` `v_(1)=g t, v_(2)=u-g t, (v_(2))/(v_(1)) =(u-g t)/(g t) =(u)/(g t)-1` `rArr (v_(2))/(v_(1)) =(h)/(g t^(2) )-1 =(hng)/(g2h)-1 rArr (v_(1))/(v_(2))=(2)/(n-2). `  .
|
|
| 14. |
An electric dipole consisting of two opposite charges of 2 xx 10^-6 each separated by a distance of 3 cm is placed in all electric field of 2 xx 10^5 newton/coulomb. The maximum torque acting on the dipole in S.I. unit will be |
|
Answer» `12 XX 10^-1` |
|
| 15. |
A point charge is kept at the centre of circular face of a cylinder of radius r and length r. Find the electric flux through remaining curved surface (i.e., other than circular face) |
| Answer» SOLUTION :`Q/(2in_0)1/sqrt2` | |
| 16. |
Three of the quantities defined below has the same dimensional formula. Identify the i) sqrt("Energy/mass") ii) sqrt("Pressure/density") iii) sqrt("force/linear density") iv) sqrt("Angular frequency/radius") |
| Answer» Answer :D | |
| 17. |
A seconds pendulum is suspended from the roof of a bus. The time period of oscillation when the bus is moving along a straight horizontal road with uniform acceleration is |
|
Answer» `2 s` |
|
| 18. |
Which of the following is the most precise device for measuring length |
|
Answer» a VERNIER callipers with 20 DIVISIONS on the sliding scale |
|
| 19. |
A particle of mass .m. is driven by a machine that delivers constant power .k. walts. If the particle starts from rest the force on the particle at time .t. is |
|
Answer» `sqrt(2mk)t^(-1//2)` |
|
| 20. |
The object at rest suddenly explodes into three parts with the mass ratio 2:1:1.The parts of equal masses move at right angles to each other with equal speed 'v'. the speed of the third part after explosion will be |
|
Answer» V |
|
| 21. |
The circular scale head of a screw gauge is divided into 200 divisions and move 1 mm ahead in one revolution. The diameter of the wire, when the pitch scale reading shows 6mm (when the wire is firmly held between the studes) and 45^(th) division on circular scale coincides with the reference line. |
|
Answer» 6.220 MM |
|
| 22. |
(A): No work is done by the centripetal force acting on a body moving along the circumference of a circle (R) : At any instant, the motion of the body is along the tangent to the circle whereas the centripetal force is along the radius vector towards the centre of the circle |
|
Answer» Both .A. and .R. are TRUE and .R. is the CORRECT EXPLANATION of .A. |
|
| 23. |
The velocity of a body revolving in a vertical circle of radius .r. at the lowest point sqrt(7gr). The ratio of maximum to minimum tensions in the string is |
|
Answer» `8:1` |
|
| 24. |
Four identical metal plates are arranged as shown plates 1 and 4 are connected by a connecting wire. A battery of emf V volts is connected between plates 2 and 3. The electric field between plates 3 and 4 is (2V)/(Kd). Find the value of K |
|
Answer» |
|
| 25. |
A ball of mass 100g is projected vertically upwards from the ground with a velocity of 49 m/s. At the same time another identical ball is dropped from a height of 98m to fall freely along the same path as that followed by the first ball. After some time the two balls collide and stick together and finally fall to the ground. Find the time of flight of the masses. |
|
Answer» |
|
| 26. |
The physical quantity that has no dimensions is |
|
Answer» ANGULAR velocity |
|
| 27. |
A bullet of mass M hits a block of mass M.. The transfer of energy is maximum, when |
|
Answer» `M. = M` |
|
| 28. |
If theta_(1)=(25.5+-0.1)^(@)C and theta_(2)=(35.3+-0.1)^(C), then find theta_(1)-theta_(2). |
|
Answer» |
|
| 29. |
A police van moving on a highway with a speed of 30 "km h"^(-1) fires a bullet at a thief's car speeding away in the same direction with a speed of 192 "km h"^(-1) . If the muzzle speed of the bullet is 150 "m s"^(-1), The speed with which the bullet hit the thief's car is |
|
Answer» 42m/s |
|
| 30. |
The ratio of S.I unit of universal gravitational constant to C.G.S. unit is |
|
Answer» `10^(3)` |
|
| 31. |
If the Earth were to suddenly contact to half its present radius, by how much would the day time decrease ? |
|
Answer» Solution :From the law of conservation of angular momentum, `I_1omega_J=I_2omega_2` where `omega_1=(2pi)/(T)` hence `(I_1)/(T_1)=(I_2)/(T_2)` where I=`2/5MR^2` if M remains the same, then `T_2=((R_1)/(R_1))^2.T_1((1R)/(2R))^2(24)=6`hr. `:. /_\T=24-6=18`hr. DECREASE in the period of ROTATION is 18 hr. |
|
| 32. |
When a cylindrical tube is dipped vertically into a liquid, the angle of contact is 140^@. When thetube is dipped with an inclination of 40^@, the angle of contact is |
| Answer» Answer :B | |
| 33. |
A uniform rod is of length 6 m and mass 12 kg. One end of this rod is hinged to a point at a depth 3 m below the free surface of water. Find (1) the weight to be suspended at the other end, so that mof length of the rod remains immersed in water, (ii) the magnitude and direction of the reaction at the hinge (spgravity of the material of the rod 0.5) |
|
Answer» Solution :The ROD makes angle with the vertical shapecose`theta=(3)/(5)` and sin `theta=(4)/(3)`Let .a. be the area of cross section of the rod. `THEREFORE` weight of the rod mg (6) 500 g N, Force of buoyancy F = (5A) 1000 g N IF W N be the weight at the end (required), then taking moments about the hinge and equating it to zero for rotatory equilibrium),(5000ag)2.5 sin `theta`)-(3000 AG)3 sin `theta`-W (6 sin `theta`)=0 Since sin `thetanetheta` ,so cancelling ag sin `theta` throughtout. 12500-9000-`(6W)/(ag)=3500implies(w)/(g)=(3500)/(6)a`  Now, the mass of the rod=12 kg `IMPLIES(6a)xx500=12impliesa=(1)/(250)m^(2)` `therefore (W)/(g)=(3500)/(6xx250)=2.33 kg` wt. or W=22.837 N ii)Now, upthrust F=`5000 xx(1)/(250)` g=20 gN IFR be the verical reaction (up) at the hinge, then for vertical equlibrium of the rod, R+F-mg - W=0 `impliesR+20g-12g-2.33g=0implies`R=-5.67kg 2t.(or) -55.57N The -Ve sign implies that ,the reaction is downwards of magnitude 55.57N |
|
| 34. |
A car starts from rest and moves with constant acceleration and covera the distance between two point 180 m apart in 6 s. Itsspeed as it passes the second point is 45 ms^(-1) Find a. Its acceleration b. Its speed when it was at the point c. The distance from the first point when it was at rest. |
|
Answer» `v=u+at rArr 45=u+axx6`  . Solve to get `u=15 m s^(-1)`, `a= 5 m s^(-2)` `u^(2)=0^(2)+2ax rArr 15^(2)=0^(2) + 2 xx5x rArr `x=22.5 m`. |
|
| 35. |
A man of mass 60kg sitting on ice pushes a block of mass of 12kg on ice horizontally with a speed of 5ms^(-1).The coefficient of friction between the man and ice and between block and ice is 0.2. If g =10 ms^(-2), the distance between man and the block, when they come to rest is |
|
Answer» 6m |
|
| 36. |
The potential energy of a simple harmonic oscillator when the particle is halt way to its end point is (E is total energy) .......... . |
|
Answer» `(2)/(3)E` `PE_(v_(2))=(1)/(4)E` |
|
| 37. |
Two metals are mixed together is equal volume to form an alloy of specific gravity 4. When equal masses of the some two metals are mixed together the specific gravity of the alloyis 3. the specific gravity of each metal is |
|
Answer» 4 and 6 |
|
| 38. |
Two blocks, of masses M and 2M are connected to a light spring of spring constant K that has one end fixed, a shown if fig. The blocks are released from the spring at its natural length codition. |
|
Answer» Maximum extention in the spring is `(4Mg)/K` |
|
| 39. |
40. Which of the diagrams correctly shows the change in kinetic energy of an iron sphere falling freely in a lake having sufficient depth to impart it a terminal velocity ? |
|
Answer»
|
|
| 40. |
Mass of two substances are 1 g and 9 g respectively. If their kinetic energies are same, then the ratio of their momentum will be…………… |
|
Answer» `1:9` If the KE are same `(P_1)/(P_2) = SQRT((m_1)/(m_2)) = sqrt(1/9) = 1/3impliesP_1 : P_2 = 1:3` |
|
| 41. |
A ring is made to rotate about its diameter at a constant angular speed of omega_(0) . A small insect of mass m walks along the ring with a uniform angular speed omegarelative to the ring (see figure). Radius of the ring is R. (a) Find the external torque needed to keep the ring rotating at constant speed as the insect walks. Express your answer as a function of theta. Forwhat value of q is this torque maximum?[given your answer for 0 le theta le 90^(@) ] (b) Find the component of force perpendicular to the plane of the ring, that is applied by the ring on the insect. For what value of thetais this force maximum? Argue quantitatively to show that indeed the force should be maximum for this value of theta. [Give your answer for 0^(@) le theta le 90^(@) ] |
|
Answer» (b) `F _|_ = 2 m R omega_(0) omega COS theta; theta = 0^(@)` |
|
| 42. |
Showhow impulse force can be measured graphically |
Answer» SOLUTION :
|
|
| 43. |
A man of mass M hanging with a light rope which is connected with a balloon of mass m. the system is at rest in air. When man rises a distance h with respect to balloon find. The distance raised by man |
|
Answer» `(mh)/(m+M)` SINCE no external force is acting `:.` COM should be at rest `Deltay_(CM)=(m_(1)y_(1)+m_(2)y_(2))/(m_(1)+m_(2))` Let baloon DESCENT by a DISTANCE x. `O=(m(x)+M(h-x))/(m+M)` `ML=(m+M)x` `x=(Mh)/(m+M)`(Distance descend by balloon ) `L-x=(mh)/(m+M)`(distance raised by man) 
|
|
| 44. |
Moment of inertia of a straight wire about an axis perpendicular to the wire passing through one of its end is I. Now the same wire is bent into a ring of two turns , then the moment of inertia would be |
|
Answer» `((pi^(2))/(3))L` |
|
| 45. |
A body of mass 20kg is moving along a straight line with a linear momentum of 240 kg ms^(-1). If a constant force of 20N acts for 5s opposite to direction of motion, the work done by the force during this time is |
|
Answer» 950J |
|
| 46. |
(A): The elastic potential energy of spring increases when it is elongated and decreases when it is compressed.(R) : Work done on a spring is independent of the force constant of the spring. |
|
Answer» Both (A) and (R) are TRUE and (R) is the CORRECT explanation of (A) |
|
| 48. |
How does the internal energy change when the ice and wax melt at their normal melting points? |
|
Answer» INCREASES for ICE and DECREASES for wax |
|
| 49. |
Statement I: Tiny drops of liquid resist deforming forces better than bigger drop. Statement II: Excess pressure inside a drop is directly proportional to surface tension. |
|
Answer» STATEMENT I is TRUE, statement II is true , statement II is a CORRECT explanation for statement I. |
|
| 50. |
Plot the corresponding SHM of particle. Indicate the intial (t=0) position of the particle, the radius of the circle and angular speed of the rotating particle. Consider sense of rotation to be anticlockwise and x in cm and tis in s. (a) =-2sin(3t(pi)/(3)) |
|
Answer» SOLUTION :`x=-2sin (3t+(PI)/(3))]=2cos [(pi)/(2)+(3t+(pi)/(3))]` `x=2cos(3t+(5pi)/(6))` Comparing this with `x=A cos (omegat+phi),` we get `A=2cm, omega="3 rad s"^(-1), phi=(5pi)/(6)" rad."` 
|
|
