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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 boyweighing 42 kg eats bananas whose energy is 980 calories. If this energy is used to go toheight h find the vlaue of h (J = 4.2 J/calorie) |
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Answer» SOLUTION :ENERGY GAINED by the BOY in eating bananas `=980" calories " =980xx4.2J`. If m is the mass of the boy, the potential energy gained by the boy in going up THORUGH a height h is mgh. In SI, energy = potential energy `rArr 980 xx 4.2=` mgh `980 xx 4.2 = 4.2 xx 9.8 xx h rArrh = (980 xx4.2)/(42xx9.8) = 10m` |
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| 2. |
A hollow equi convex lens of glass will behave like a |
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Answer» SOLUTION :Hollow convex lens is as shown in figure `1/(f_1 )= (mu_e-1) (1/R_1-1/R_2) =0` or `f_1= infty`, Similarity `f_2= infty ` Therefore, a hollow equi convex lens of any material will behave LIKE a glass PLATE. 
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| 3. |
A metal meter scale has two holes at the two ends. when the scale is heated the distance between the two holes |
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Answer» decreases |
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| 4. |
Two wires of the same length and material but of different radii are suspended from a rigid support.Both carry the same load.Will the stress,strain and extension in them be same or different? |
| Answer» Solution :(a)Stress=`F//pi r^2` for the same load F stress is DIFFERENT for different radii. (b)`Y=FL//A` delta L,Strain,` delta L//L=F//AY=F//pi r^2Y` so strain also be different.(c)Elongation `delta L=FL//pi r^2Y,delta L PROP 1//r^2` for a fixed F,L,Y so elongation will not be the same., Hence stress strain and extension area all different for the two WIRES. | |
| 5. |
A block is placed at distance of 2m from the rear on the floor of a truck (g=10 ms^(-2)). When the truck moves with an acceleration of 8ms^(-2), the block takes 2 sec to fall off from the rear of the truck. The coefficient of sliding friction between truck and the block is |
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Answer» `0.5` |
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| 6. |
The rear side of a truck is open and a box of 40 kg mass is placed 5 m away from the open end as shown in figure. The coefficient of friction between the box the surface below it is 0.15. On a straight road, the truck starts from rest and accelerates with 2ms^-2). At what distance from the starting point does the box fall from the truck ? (Ignore the size of the box.) |
| Answer» Solution :`s=(1)/(2)at^(2), a^(1)=a-mug, t=sqrt((2L)/(a^(1)))` | |
| 7. |
Assertion : Hydraulic lift work on Pascal's law. Reason :Pressure is equal to force acting per unit. |
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Answer» Both ASSERTION and REASON are TRUE and the reason is the CORRECT EXPLANATION of the assertion. |
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| 8. |
From a point on the ground, the top of a tree is seen to have an angle of elevation 60^(@). The distance between the tree and a point is 50 m. Calculate the height of the tree? |
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Answer» Solution :Angle `THETA = 60^(@)` The distance between the tree and a POINT X = 50 m Height of the tree (h) = ? For TRIANGULATION method `tan theta = h/x` `h = x tan theta = 50 xx tan 60^(@) = 50 xx 1.732` h = 86.6 m The height of the tree is 86.6 m. |
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| 9. |
A particle, moving along the x-axis, executes simple harmonic motion when the force acting on it is given by (A and k are positive constant.)……………… |
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Answer» `-AKX` |
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| 10. |
Accordig to Law of equipartition of energy, for any dynamical system in thermal equilibrium, the total energy in distributed equality amongst all the degrees of freedom. The energy associated with each molecule per degree of freedom is (1)/(2) k_(B)T where k_(B) is Boltzmann constant and T is temperature of the system. the law emphasises that in thermal equilibrium, at temperature T, each more of energy : translation, rotational and vibrational, contribute an average energy equal 1/2 k_(B)*T Read the above passage and answer the following questions : (i) What is the internal energy of one gram mole of a polyatomic gas having an degree of freedom ? (ii) What value of life do you learn from this law ? |
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Answer» Solution :(i) INTERNAL energy of one molecules of gas having N DEGREES of freedom = ` n xx 1/2 k_(B)T`. If N is AVOGARDRO's number, then internal energy of one gram mole of the gas `U=n xx 1/2 k_(B) T xx N = n/2 RT` , Where `R = k_(B) xx N `= gas constant for one gram mole of the gas. (II) The law emphasises that total energy is distributed equally amongst all the degrees of freedom. There is no preferreddegree of freedom. so is true in nature. God has distributed equally all the natural resources without any distinction of nation, cast or creed. In day to day life, we should not distinguish people on the basis of colour, cast or creed. everyone should be treated equally with love, affection and mutual respect. |
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| 11. |
A stone is projected at an angle of tan^(-1)(3//4)to the horizontal with a speed of 30ms^(-1). Find its position after 2 seconds. g=10ms^(-1)? |
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Answer» |
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| 12. |
A train runs along an unbanked circular track of radius30 m at a speed of 54 km/h . The mass of the train is 10 kg. What provides the centripetal force required for this purpose- The engine or the rails ? What is the angle of banking required to prevent wearing out of the rail ? |
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| 13. |
A force of constant magnitude starts acting on a moving particle when it is at some point 'P'. Depending on the orientation of the force, the particle may (a) pass through point P at some time later(b) not return to point P(c ) describe a circular path(d) describe a parabolic path |
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Answer» a is CORRECT |
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| 14. |
A clock whose pendulum makes one complete oscillation in two seconds is correct at 25^(@)C. The pendulum shaft is of steel and thin. What is the fractional change in the length of the shaft when it is heated to 35^(@)C? How many seconds per day will the clock gain or lose at 35^(@)C? alpha=11xx10^(-6)(C^(@))^(-1). |
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Answer» |
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| 15. |
One litre of helium gas at a pressure of 76 cm-Hg and temperature 27^@C is heated till its pressure and volume are doubled. The final temperature attained by the gas is |
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Answer» 900°C |
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| 16. |
If same force is applied on a light and a heavy object on same surface, then work done on heavy object is more. |
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Answer» |
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| 17. |
A carnot engine is operated between two reserviors at temperatures of 500 K and 400 K. The engine receives 840 Joules of heat from the source in each cycle. Calculate (a) the amount of heat rejected to sink in each cycle (b) the efficiency of the engine, and (c) the work done in each cycle. |
| Answer» Solution :`Q _(2) = T _(2) Q _(1) //T_(1) = 400 XX 840 //500 = 672 J, ETA = 500 - 400 // 500 = 0.2, W = 0.2 xx 840 = 168 J` | |
| 18. |
Drw graphs of beat produced by two harmonic waves of frequency 11 Hz and 9 Hz. |
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Answer» Solution :The time-displacement GRAPHS of two waves of FREQUENCY 11 Hz and 9 Hz are shown in FIGURE (a) and (b). The result of their .SUPERPOSITION. is shown in figure (c ). 
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| 19. |
A planet of mass .m. moves in an elliptical orbit around an unknown star of mass .M. such that its maximum and minimum distances from the star are equal to r_1 and r_2respectively. The angular momentum of the planet relative to the centre of the star is |
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Answer» `msqrt((2GMr_1r_2)/(r_1+r_2))` |
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| 20. |
The average kinetic energy of a gas at -23^@C and 75 cm pressure is 5xx 10^(-14) erg for H_2. The mean kinetic energy of the O_2" at "227^@C and 150 cm pressure will be |
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Answer» `80 xx 10^(-14)ERG` |
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| 21. |
Define 1 eV: |
| Answer» Solution :The amount of energy GAINED ( or LAST ) by the charge of a single electron moving across an electron POTENTIAL DIFFERENCE of ONE volt . | |
| 22. |
Jagaseesh was rotating a stone tied to an elastic rubber band. As time passes he kept on increasing its speed of rotation. As the speed increased, the length (i.e. radius) of the band was also increasing. His father Mr. Sridhar watched this and called Jagadeesh. When Jagadeesh came near by his father rotating the stone tied to the elastic band, he asked how this happened? (ii) What are Apogee and Perigee? |
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Answer» SOLUTION :Jagadeesh father Mr. Sridhar EXPLAINED this is related to Kepler's III law of planetary motion. He explained that time period of rotation of any object (say planets moving around sun) does not depend on the VELOCITY of the object and radius of the circular path it means, whatever be the radius of the circular path or the velocity of the object, time periodwill not change at all. So you can measure the Time period of rotation of this stone too for different velocities (i.e. radius too is changing). Jagadeesh was surprised about his father's knowledge. (ii) Apogee or Aphelion is the position of the planet, where it is very FAR away from the sun. Perigee or Perihelion is the POSTION of the planet, where it is very close to the sun. |
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| 23. |
Which of the following rule is applied to know the diretion of the vectors product ? |
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Answer» FLEMING's left handrule |
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| 24. |
A torque tau on a body about a given point is found to be equal to vec(C)xxvec(L), where vec(C) is a constant vector and vec(L) is the angular momentum of the body about point. From this, its follows that |
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Answer» `VEC(L)` Does not change with time |
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| 25. |
A particle moves with a velocity (5hati-3hatj+6hatk) m/s under the influence of a constant force vecF = (10hsti+10hatj+20hatk) N. The instantaneous power applied to the particle is |
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Answer» Solution :As `vecv = (5 HATI + 6 hatk) m//s, vecF (10 hati + 10 hatj + 20 hatk) N` `:.` Power = `vecF. Vecv = (10 hati + 10 hatj + 20 hatk). (5 hati - 3hatj + 6hatk)` `= 50 - 30 + 120 = 140 W` |
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| 26. |
An air bubble of diameter 2 cm is allowed to rise through a long cylindrical column of viscous liquid and travels at the rate of 0.21 cm s^(-1) . If the density of the liquid is 1.47 g cm^(-3).find the coefficient of viscosity. Density of air is neglected. |
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| 27. |
Jagaseesh was rotating a stone tied to an elastic rubber band. As time passes he kept on increasing its speed of rotation. As the speed increased, the length (i.e. radius) of the band was also increasing. His father Mr. Sridhar watched this and called Jagadeesh. When Jagadeesh came near by his father rotating the stone tied to the elastic band, he asked how this happened? (i) State Keper's III law and give an expression. |
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Answer» Solution :JAGADEESH father Mr. Sridhar explained this is related to Kepler's III LAW of planetary motion. He explained that time period of rotation of any object (say planets MOVING around sun) does not depend on the velocity of the object and radius of the circular path it means, whatever be the radius of the circular path or the velocity of the object, time periodwill not change at all. So you can measure the Time period of rotation of this stone too for different velocities (i.e. radius too is changing). Jagadeesh was surprised about his father's knowledge. (i) Kepler's III lae states that "The square of the period of revolution of a planet around the sun is directly proportional to the cube of the mean distance between the planet and the sun. `T^(2) prop r^(5)` `(T^2)/(r^3)` = a constant. |
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| 28. |
If an object is moving in a straight line then the motion is known as ................ Motion |
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Answer» linear |
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| 29. |
If ltTgt and ltUgt denote the average kinetic and the average potential energies respectively of a mass executing a simple harmonic motion over one period, then the corresponding relation is |
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Answer» `LTTGT =-2ltUgt` |
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| 30. |
One likes to sit under sunshine in winter season, becaus |
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Answer» The air surrounding the body is HOT by which body gets HEAT |
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| 31. |
Match Column-I with Column-II : {:("Column-I","Column-II"),("(1) Zero work done","(a) by gravitational force"),("(2) Positive work done","(b) opposite to gravitational force"),("(3) Negative work done","(c) by centripetal force"):} |
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| 32. |
Which of the following methods will enable the volume of an ideal gas to be made 4 times |
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Answer» Absolute temperature and PRESSURE must be doubled |
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| 33. |
A jet engine works on the principle of |
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Answer» CONSERVATION of LINEAR momentum |
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| 34. |
What is an ideal fluid? |
| Answer» Solution :An IDEAL fluid is INCOMPRESSIBLE, i.e., the DENSITY or volume of that fluid does not change on PRESSING it. It is non VISCOUS too. There is no tangential force acting between two adjacent layers of that fluid. | |
| 35. |
Excess pressure can be (2T/R) for |
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Answer» SPHERICAL drop |
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| 36. |
A particle is projected from point A to hit an apple as shown in (Fig. 5.195). The particle is directly aimed at the apple. Show that particle will not hit the apple. Now show that if the string with which the apple is hung is cut at the time of firing the particle, then the particle will hit the apple. . |
| Answer» SOLUTION :The apple will not FALL in the path of the trajectory of the particle. Hence, the particle will not hit the apple. But when the string is cut, the vertical fall of apple and the particle will be EQUAL. Hence the particle WILLL hit apple. | |
| 37. |
The level of water in a huge tank is 20 m. Nearly at the bottom of the tank, there is a hole of 2 cm? cross section. The rate with which the water will leak through the hole is n xx 10^(-3) cm. Find the value of n. |
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Answer» Solution :As RATE of FLOW of WATER `=av =2 xx 10^(-4) sqrt(2gh)` `=2 xx 10^(-4) sqrt(2 xx 10 xx 20)` `=2 xx 10^(-4) xx 20` `=4 xx 10^(-3) m` |
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| 38. |
A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement x is proportional to : |
| Answer» ANSWER :A | |
| 39. |
Gravel is dropped on a conveyer belt at the rate of 0.5 kg/ sec . Find the extra force required in Newton to keep the belt moving at 2m/sec. |
| Answer» SOLUTION : `F= ((DM)/(DT))xxv=0.5xx2=1N` | |
| 40. |
A block of ice at -10^@Cis slowly heated and converted to steam at 100^@CWhich of the following curves represents the phenomenon qualitatively? |
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Answer»
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| 41. |
A boy throws a ball with a velocity of 15 m/s at an angle of 15° with the horizontal. The distance at which the ball strikes the ground is |
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Answer» 5m |
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| 42. |
Which law of Newton reveals the underlying symmetry in the forces that occur in nature ? |
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Answer» FIRST law |
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| 43. |
An aircraft after covering a distance of 100 m on the ground, acquires a velocity of 80 "km."h^(-1).Mass of the aircraft is 10^(4) kg and its coefficient of friction with the ground is 0.2. Assuming that the acceleration of theaircraft on ground is constant, what minimum force has been applied by the engine to obtain this acceleration? |
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| 44. |
"It is difficult to move a cycle along the road with its brakes on". Why? |
| Answer» SOLUTION :When the brakes are on there is no ROLLING of the wheels and the wheels SLIDE. The sliding friction is GREATER than the rolling friction. So it is difficult. | |
| 46. |
The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is -20^@C, the temperature of the surroundings to which it rejects heat is. |
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Answer» `21^(@)C` `T_(1)=((K+1)/(K))T_(2)=(6)/(5)xx253=303.6K` `T_(1)=20.6^(@)C` |
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| 47. |
Read the following passages carefully and answer the questions at the end of them. A ball of mass 200 g is thrown with a speed 20 mcdot s^(-1). The ball strikes a bat and rebounds along the same line at a speed of 40 m cdot s^(-1). Variation in the interaction force, as long as the ball remains in contact with the bat, is shown in .What is the speed of the ball at the instant the force acting on it is maximum? |
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Answer» 40 m`cdot s^(-1)` |
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| 48. |
A spherical planet far out in space has a mass M_0 and diameter D_0A particle of mass .m. falling freely near the surface of this planet will experience an acceleration due to gravity which is equal to |
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Answer» `(GM_0)/D_0^2` |
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| 49. |
An inclined track ends is a circular loop of diameter D. From what height on the track a particle should be released so that it completes that loop in the vertical plane? |
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Answer» `(5D)/2` |
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| 50. |
The motion of a particle is expressed by the equation a=-bx, where x is the displacement from the mean position, a is the acceleration and b is a constant. The periodic time is…………… |
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Answer» `(2pi)/(b)` |
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