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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. |
A block of mass 1kg is attached to one end of a spring of force constant k=20N/m. The other end of the spring is attached to a fixed rigid support. This spring block system is made to oscillate on a rough horizontal surface (mu = 0.04). The initial displacement of the block from the equilibrium position is a =30cm. How many times the block passes from the mean position before coming to rest ? (g=10m//s^(2)) |
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Answer» 5 |
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| 2. |
A flywheel in the form of a disc is initially at rest. When a constant torque acts on it for one minute, it attains a speed of 600 rpm. Calculate the torque, if mass and radius of the disc are 10 kg and 0.4m respectively. |
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Answer» SOLUTION :M = 10kg, R=0.4m `I=(MR^(2))/(2)=10((0.4)^(2))/(2)0.8kgm^(2)` `omega_(i)=0,omega_(f)=(2piN)/(t)=(2pi(600))/(60)=20pirads^(-1)` TIME taken for the change of speed,t=60 s. `alpha=(omega_(f)-omega_(i))/(t)=(20pi-0)/(60)=(pi)/(3)rads^(-1)` The torque, `tau=Ialpha=0.8((pi)/(3))=0.8379Nm`. |
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| 3. |
Eleven forces each equal to 5N act on a particule simultaneously. If each force makes an angle 30^(0) with the next one, the resultant of all forces is |
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Answer» 15N |
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| 4. |
An ideal gas expands from volume V_1 to V_2. This may be achieved by either of the three processes:isobaric, isothermal and adiabatic. Let dU be the change in internal energy of the gas, Q be the quantity of heat added to the system and W be the work done by the system on the gas. Identify which of the following statements is false for dU? |
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Answer» dU is least under ADIABATIC process |
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| 5. |
For a planet moving around the Sun in an elliptical orbit of semimajor and semiminor axes a and b respectively and Time period T.For this situation which one of the following statements is correct? |
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Answer» The torque acting on the planet about the Sun in non-zero |
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| 6. |
A refrigerator takes a quantity of heat 'Q' from the cold body, with work done 'W' on it, transfers heat to the hot body.(a) What does the ratio Q/W represent? |
| Answer» SOLUTION :COEFFICIENT of PERFORMANCE | |
| 7. |
A simple pendulum consisting a ball of mass 'm' tied to a string of length 'I' is made t showing on a circular arc of angle 'q' ina vertical plane. At the end of this arc, another ball of mass 'm' is placed at rest. The momentum transferred to the ball at rest by swinging ball is |
| Answer» Answer :D | |
| 8. |
A block is hanged by means of two identical wires having cross-section area A (1"mm"^2) as shown in the figure. If temperature is lowered by Delta T (10^(@) C), find the mass ("in kg") to be added to hanging mass such that junction remains at its initial positions. Given that coefficient of linear expansion alpha=2 xx 10^(-5) I^(0) C and Young's modulus Y= 5 xx 10^(11) N//m^(2) for the wire. |
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Answer» |
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| 9. |
If Young's modulus of the material of a rod is Y and density is rho then time taken by sound wave to travel l length from bottom is |
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Answer» `lsqrt((rho)/(Y))` |
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| 10. |
A certain block weighs 15N in air. But it weighs only 12N when completely immersed in water. When immersed in another liquid, it weighs 13N. Calculate the relative density of (1) the block and (ii) the liquid. |
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Answer» Solution :(i)`RD_(B)-=(rho_(b))/(rhoH_(2)O)=(rho_(b)V_(b)g)/(B_(H_(2))O)=(W_(air))/(W_(air)-W_(H_(2))O)`:Where `W_(air)`=15N (weight of the body in air) and `WH_(2)O=12N`(weight of the body in water) `there R.D_(B)=(15N)/(15N-12N)=5` (II)`(rho_(b))/(rho_(L))=(rho_(b)V_(B)g)/(rho_(L)V_(B)g)=(m_(B)g)/(B_(L))=(W_(air))/(W_(air)-W_(L))` where `W_(L)`=13N (weight of the body in liquid) `therefore (rho_(b))/(rho_(L))=(R.D_(B))/(R.D_(L))=(15N)/(15N-13N)=(15N)/(2N)therefore R.D_(L)=(2)/(3)` |
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| 11. |
Find the component of 3hat(i)+4hat(i) along hat(i)+hat(j) ? |
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Answer» SOLUTION :Component of `vec(A)` ALONG `vec(B)` is given by `(vec(A).vec(B))/(B)=((3HAT(i)+4hat(j)).(HAT(i)+hat(j)))/(SQRT(2))=(7)/5rt2) |
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| 12. |
A certain quantity of air is adiabatically compressed so that its pressure increases from 1 atmosphere to 150 atmosphere. If the initial temperature of air is 27^(@)C. Calculate (i) rise in temperature and (ii) the work done of air Y= 1.4). |
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Answer» <P> Solution :`T _(2) = (P_(2) //P_(1)) ^((gamma -1) lgamma) xx T_(1)= (150 //1) ^((1.4 - 1) //1.4) xx 300 = 1255.63 K, W = R ( T _(1) - T _(2)) //gamm-1 = 8.3 xx (300 - 1255.6 62//0.4 ) =- 19829.1 J` |
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| 13. |
What is the phase difference between consecutive crest and through ? |
| Answer» SOLUTION :`pi/2` RAD ` | |
| 14. |
A particle is projected with a certain velocity at an angle alpha abovethe horizonta form the foot of an inclined plane of inclination30^(@). If the particle strikes the plane normally thenalpha is equal to |
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Answer» `30^(@)+tan^(-1) (SQRT(3)/2 )` |
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| 15. |
In an experiment, a physical quantity is given by Y=(a^(2)b)/(c^(3)). The permissible percentage error |
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Answer» `((Delta a)/(a)+(Delta B)/(b)+(Delta C)/(c ))xx100` |
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| 16. |
The rate of steady volume flow of water through a capilary tube of length and radius r under a pressure difference of Pis V. This tube is connected with another tube of the same length but half the radius in series. Then the rate of steady volume flow through them under same pressure difference across the combination is |
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Answer» `(V)/(16)` |
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| 17. |
If the area swept by the line joining the sun and the earth from Feb 1 to Feb 7 is ‘A’, then the area swept by the radius vector fromFeb 8 to Feb 28 is |
| Answer» ANSWER :C | |
| 18. |
Determine the kinetic energy of a circular disc rotating with a speed of 60 rpm about an axis passing through a point on its circumference and perpedicular to its plane. The circular disc has a mass of 5kg and radius 1m. |
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Answer» SOLUTION :Kinetic ENERGY K.E`=(1)/(2)Iomega^(2)=(1)/(2).(3MR^(2))/(2).(2pi)^(2)` `=148.1J` |
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| 19. |
A particle of mass m is tied with a rope and is rotated along a horizontal circular path. The length of the rope is r_(0) and the velocity of the particle is v_(0). What amount of work should be done to decrease the length of the rope to r ? |
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Answer» |
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| 20. |
n identical cubes each of amss m an side I are on the horizontal surface. Then the minimum amount of work done to arrange then one on the ther is |
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Answer» nmmgl |
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| 21. |
A roundpebble is releasedfrom the point X inside a frictionless hemisphericalball as shownin the figure suchthatit justuptoedgeYof the bowl . With what speedthe pebbleis releaseddown insidethe bowl? |
Answer» Solution : Let the speed of the pebble when releases from point X inside the bowlis V. Using the law of CONVERSATION of energy , Total energyat X = Total energy at Y ` :. 1/2 mv^(2) +mgd = 0 + mgR ` `rArr ""v^(2) = 2g (R-d) = 2XX 9.8 (0.07 - 0.05)` ` v = 0.626 ` m/s |
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| 22. |
Mention the type of the basic forces involved in the following situations. (i) Earth revolving around the sun, (ii) Electron revolving around the nucleus, (iii) Neutron changing into a proton emitting electron and antineutrino, (iv) The attractive forces between two protons inside the nucleus, (v) The repulsive force between two protons outside the nucleus. |
| Answer» Solution : (i) Gravitational force, (II) ELECTROMAGNETIC force, (iii) Weak NUCLEAR force, (IV) STRONG nuclear force(v)Electromagnetic force. | |
| 23. |
When a wound spring is dissolved in an acid, the temperature of the acid |
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Answer» Increases |
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| 24. |
A truckand a car moving with the same K.E. on a stright road. Their engines are simultaneously switched off which one will stop at a lesser distance ? |
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Answer» Solution :By `"work"="Energy"` THEOREM. `"Loss in K.E.=W.D. against the force" xx "distance of fricition"` or `K.E.=mumgS` `"For CONSTANT K.E., S"infty1/m` THEREFORE Truck will STOP in a lesser distance because of greater mass. |
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| 25. |
Every great physical theory starts as a hearsay and ends as a dogma. Given some exaples from the history of science, of the validity of this incivise remark. |
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Answer» Solution :The statement is true. For example in ANCIENT times, Ptolemy postulated that earth is stationary and all the HEAVENLY bodies like SUN, plents etc. revolve AROUND earth. Later, an Italian scientist, Galieo postulated that sun is stationary and earth alongwith other planets is revolving around the sun. Galileo was punished by the then authorities for spreading wrong concepts. However, later on Newton and Kepler supported Galileo's theory and now it is no more then a dogma. |
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| 26. |
The vector sum of a system of non-collinear forces acting on a rigid body is given to be non-zero. If the vector sum of all the torques due to the system of forces about a certain point is found to be zero, does this mean that it is necessarily zero about any arbitrary point? |
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Answer» SOLUTION :No, not necessarily. It is possible that VALUE of the torque is DIFFERENT at different POSITION. |
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| 27. |
Two particles each of the same mass move due north and due east respectively with the same velocity .V.. The magnitude and direction of the velocity of centre of mass is |
| Answer» Answer :A | |
| 28. |
Two particles of equal mass m move around a circle of radius R under the influence of their mutual gravitational attraction, the speed of each particle with respect to their center of mass will be .......... |
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Answer» `SQRT((Gm)/(R))`  `mv^2 /R = (GMm)/((2R)^2)` `(mv^2)/R =(GMm)/(4R_e^2)` `:. v_2^2 =(GM)/(4R)` `:.v = sqrt((GM)/(4R))` |
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| 29. |
A man swimming down stream overcome a float at a point M. After travelling distance D he turned back and passed the float at a distance of D/2 from the ration of speed of swimmer |
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Answer» 2 |
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| 30. |
Read each statement below acrefully and state , with reasonsand examples , if it istrue or false :A scalarquantity is one that (a) is conserved in a process (b)can never take negative values (c ) must be dimensionless (d) does not very from one point to another in space ( e) has the same valuefor observers with different orientations ofaxes. |
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Answer» |
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| 31. |
Two bodies at different temperatures T_1 and T_2 if brought in themal contact, do not necessarily settle to the mean temperatureT_1+T_2/2.Why? |
| Answer» SOLUTION :They MAY have DIFFERENT MASSES and different specific HEATS. | |
| 32. |
Assertion : Sound wave cannot propagate through vacuum but light can. Reasion : Sound wave cannot be polarised but light can. |
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Answer» Both ASSERTION and reason are true and reason is the correct EXPLANATION of the assertion Being electromanetic waves, lieght waves can travel through vacuum. |
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| 33. |
An artificial satellite is revolving in a circular orbit at a height of 1200km above the surface of the earth. If the radius of the earth is 6400km, mass is 6xx10^(24) find the orbital velocity (G=6.67xx10^(-11)Nm^(2)//kg^(2)) |
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Answer» Solution :`V_(0)SQRT((GM)/(R+h))=sqrt(((6.67xx10^(-11))(6XX10^(24)))/((6400xx10^(3))+(1200xx10^(3))))` `=sqrt((6.67xx10^(-11)xx6xx10^(24))/(7600xx10^3))=7.26km//s` |
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| 34. |
An aeroplane requires a speed of 72kmph for a take off with 150m run on the ground. The mass of the plane is 1500kg and the coefficient of friction between the aeroplane and the ground is 0.4. Assuming that the aeroplane acceleration uniformly during take off, find the minimum force exerted by the engine of the aeroplane for take off. |
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Answer» 8500N |
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| 35. |
A mass placed on an inclined plane is just in equilibrium. If mu is the coefficient of friction of the surface, then maximum inclination of the plane with the horizontal is |
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Answer» `TAN^(-1)MU` |
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| 36. |
A lift is going up with uniform velocity. When brakes are applied, it slows down. A person in that lift, experiences |
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Answer» more weight |
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| 37. |
Figure shows a light, inextensible string attached to a cart, which can slide along a frictionless horizontal rail aligned along the x axis. The left end of the string is pulled over a pulley of negligible mass and friction and fixed at height h=3m from the ground level. The cart slides from x_1=3sqrt3m to x_2=4m and during the move, tension in the string is kept constant at 50N. Find the change in kinetic energy of the cart in joules. (Use sqrt3=1.3) |
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Answer» Solution :Displacement of the point A of the STRING `SQRT((3sqrt3)^2+(3)^2)-sqrt(4^2+3^2)=6-5=1m` `DELTAK=` Work DONE by tension `=50xx1=50J` |
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| 38. |
(A) : For a body projected horizontally from the top of a tower, the velocity on reaching the ground depends both on velocity of projection and height of the tower . ( R) : For a projectile velocity varies both in horizontal and vertical directions. |
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Answer» Both (A) and ( R) are ture and ( R) is the CORRECT EXPLANATION of (A) |
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| 39. |
In the elastic collision between two billiard balls. The variation of potential energy is represented by the graph (here r is the distance between centres of the balls and R is radius of the ball) |
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Answer»
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| 40. |
An artificial satellite moving in a circular orbit around the earth has a total energy E_(0)(PE+KE) its potential energy is |
| Answer» ANSWER :C | |
| 41. |
Which of the following statements is not true about angle of contact ? |
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Answer» The value of contact for pure water and glass is zero |
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| 42. |
Ina two particle system, one particle lies at origin another one lies at a distance of X. Then the position of center of mass of these particlesis |
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Answer» `(m_(2)X_(2))/(m_(1)+m_(2))` |
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| 43. |
Acceleration of a particle at any time t is given by bar(a)=(2 ti + 3 t^(2)j)m//s^(2) vec(AB). If initially the particle is at rest, the velocity of the particle at t=2s is |
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Answer» `(4i+8j)m//s` |
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| 44. |
A golfer takes his ball into the hole in the three strokes.The first stroke displaces the ball 4 m north , the second stroke 2 m south-east, and the third stroke 1 m south-west.What displacement would have been needed to get the ball into the hole in the first stroke ? |
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Answer» |
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| 45. |
From the following paramenters, select the odd man out . |
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Answer» TIME of FLIGHT |
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| 46. |
The pressure P and volume V of an ideal gasboth increase in a process |
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Answer» It is not POSSIBLE to have such a process |
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| 47. |
If two balls are projected at an angle of 60^(@) and 45^(@) and the total heights reached are same, then their initial velocities are in the ratio of ___ |
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Answer» `2sqrt(2):3` `((mu_(1))/(mu_(2)))^(2)=(sin^(2)theta_(2))/(sin^(2)theta_(1))=(((1)/(sqrt(2)))^(2))/(((sqrt(3))/(2))^(2))=(1)/(2)xx(4)/(3)=(2)/(3)` `u_(1):u_(2)=sqrt(2):sqrt(3)` |
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| 48. |
Force required to increase the length of wire of area of cross section .A. by one percent, if .Y. is young.s modulus, is |
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Answer» AY |
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| 49. |
Consider following statement A and B and identify the correct answer A: Coefficient of restitution varies between '0'0 and '1' B: In inelastic collision, the law of conservation of energy is satisfied. |
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Answer» A and B are TRUE |
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