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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. |
An object is projected horizontally from a top of the tower of height h. The line joining the point of projection and point of striking on the ground makes an angle 45^@with ground, then with what velocity the object strikes the ground |
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Answer» `SQRT((11gh)/(2))` |
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| 2. |
Why 10^(6) km cannot be represented by Mkm? |
| Answer» SOLUTION :We cannot WRITE two prefix for a GIVEN UNIT. | |
| 3. |
Figureshows a largetankof waterat constant temperatureT_(C)and a smallvessel containingclodwaterof mass m at initial temperatureT_(1) .A metal rodof lengthL., area of crossectionA andthermalconductivityk connects the two vessesl to becomes T_(2) (T_(C) lt T_(2) ltT_(1)). Thespecificheat capacityof water is c and all otherheat capacitiesare negligible . |
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Answer» Solution :Letat any time ,tthe temperatureof SMALLER vessel be Tand after a small timeinternal dt , it becomes T+ dT. Theheat TRANSFERRED from tank to small vesselin small timeinterval dt is. `DQ = KA((T_(c) - T))/(l) dt ` But dQ = me dT. `therefore` m`dT = KA(T_(C) - T)/(l) dt "" therefore (dT)/(T_(c) - T) = (KA)/(mcl) dt ` LET `tau ` be the timerequire d , thenIntegrating. `int_(T_(c))^(T_(2)) (dT)/(T_(C) - T)= (KA)/(mcl) [t]_(0)^(tau) "" [log_(e) (T_(C) - T)]_(T_(1))^(T_(2)) = (KA)/(mcl) tau rArr log_(e) ((T_(c)-T_(2))/(T_(c) - T_(1))) = (KA)/(mcl) tau ` `thereforetau = (mcl)/(KA) log_(e)((T_(c) - T_(2))/(T_(c) - T_(1)))` |
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| 4. |
An observer looks at an kept at an distance 30cm in air.If an rectangular glass plate is placed between the observer and the object with its thickness along the line of observations, the object appears to the observer to be at a distance 25cm Find the thickness of glass plate. Position of the glass plate is now shifted (i) from object towards observers (ii) from observer towards the object. How does it change the apparent position of the object as seen by the observer? |
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Answer» Solution :As a glass plate is placed between the observer and the object, the object appears to be at a distance 25CM instead of 30CM, IT IMPLIES the normal shift due to refraction at the glass plate is 30-25=5cm. Normal shift `=t(1-1/mu)` Hence `t(t-1/mu)=5 t(t-1/1.5)=5, therefore t=15cm` Since the plate has given values of refractive index (1.5) and THICKNESS (15cm) if its position is shifted if, will not change the values of normal shift `t(I-1/mu)` It implies that the object will appear to be at the same distance 25cm and its apparent position remains the same. |
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| 5. |
An inverted u-tube has its two limbs in water and kerosene contained in two beakers. If water rises to a height of 10cm, to what height does kerosene (density = 0.8 gm/cc) rise in the other limb? |
| Answer» ANSWER :B | |
| 6. |
The moment of inertia of a wheel of radius 20cm is 40kgm^(2). If a tangential force of 80N applied on the wheel , its Rotational K.E. after 4s is |
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Answer» `16.2J` |
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| 7. |
The force required to tow a car at constant velocity is directly proportional to velocity. If it requires 160W to tow a car with a velocity of 4 ms^(-1), the power it required to move the car with a velocity of 9ms^(-1) is |
| Answer» ANSWER :C | |
| 8. |
Relative velocity is |
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Answer» Apparent velocity of one when it is OBSERVED by another |
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| 9. |
(A): If same work is done on identical springs of steel and copper, steel spring is less elongated.(R) : Steel is less elastic than copper. |
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Answer» Both (A) and (R) are TRUE and (R) is the correct explanation of (A) |
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| 10. |
Two identical particles moves towards each other with velocity 2v and v respectively. Two velocity of centre of mass is ………….. |
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Answer» `v` |
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| 11. |
A ball of mass 0.2 kg is thrown in the vertical direction with a velocity of 2 m/s. At the top of its path. (1) What is the value of its velocity ? (2) What is the value of its acceleration ? (3) What is the value of the force acting on it ? |
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Answer» Solution : (1)At thetoppointfinalvelocityv= 0 `m//s` (2) At t he toppointaccelerationis CONSTANT `:. ,a =g =10 m//s^(2)` (3)ForceF =MG ` = 0.2xx 10 = 2N` |
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| 12. |
Two rain drops of equal volume , falling with terminal velocity 10cms^(-1) , merge while falling and forms a larger drop . Findthe terminal velocity of the larger drop . |
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Answer» Solution :Let the radius and volume of each DROP be r and V RESPECTIVELY. When they merge and form a larger drop , its volume V. will be double the volume of each one of them. (As the mass and density remain constant.) Let the radius of the bigger drop so FORMED be R. Now `,V.=2V` `therefore(4)/(3)piR^(3)=2((2)/(3)pir^(3))` `thereforeR^(3)=2r^(3)` `thereforeR=2^((1)/(3))r` Let the terminal velocity of the smaller drop be v and that of the larger drop be v.. `thereforev=(2)/(9)(r^(2)g)/(eta)(rho-rho_(o))and` `thereforev.=(2)/(9)(R^(2)g)/(eta)(rho-rho_(o))` `therefore(v.)/(v)=(R^(2))/(r^(2))` `thereforev.=(R^(2))/(r^(2))v=(2^((2)/(3)))xx10=15.87cms^(9-1)` |
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| 13. |
A cube is subjected to a uniform volume.compression, if the side of the cube decreases by 1% the bulk strain is |
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Answer» 0.01 |
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| 14. |
A particle suspended by a thread of length .l. is projected horizontally with a velocity sqrt(3gl) at the lowest point. The height from the bottom at which the tension in the string becomes zero is |
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Answer» `(4L)/(3)` |
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| 15. |
A rigid horizontal smooth rod AB of mass 0.75 kg and length 40 cm can rotate freely about a fixed vertical axis through its midpoint O. Two rings each of mass 1 kg initially at rest are placed at a distance of 10 cm from O on either side of the rod. The rod is set in rotation with an angular velocity of 30 radian per sec and when the rings reach the ends of the rod, the angular velocity in rad/sec is |
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Answer» 5 `therefore [(ML^(2))/(12) + 2 mr^(2) ] omega_(1) = [(ML^(2))/(12) + 2m ((L)/(2))^(2)] omega_(2)` or `[(0.75 xx (0.4)^(2))/(12) + 2 xx 1 xx (0.1)^(2) ] xx 30` `[(0.75 xx (0.4)^(2))/(12) + 2 xx 1 xx (0.2)^(2)] xx omega_(2)` or `omega_(2) = ((0.01 + 0.02) 30)/((0.01 + 0.08)) = (0.03 xx 30)/(0.09) = 10` rad/sec |
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| 16. |
In the figure S_(1) and S_(2) are two light springs of stiffness k and 4k respectively. When springs are in relaxed state, seperation between their free ends is 2x_(0) . A uniform solid cylinder of mass m and radius R( lt x_(0)) is placed exactly midway between the free ends of the springs with its axis horizontal and perpendicular to the springs . Now consider the two cases separately. Case I : The cylinder is imparted speed v_(0) towards left. When the cylinder comes to rest momentarily the co-ordinates of its centre are either (-x_(1), R) or (x_(2),R) . Case II: The Cylinder is imparted speed v_(0) toward left and angular speed omega^(0) in clockwise sense simultaneously . At the time of maximum compression in the springs the co-ordinates of centre of the cylinder are either (-x_(3),R) " or "(x_(4),R) Now answer the following questions assuming that friction is absent every where. The value of x_(3) is |
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Answer» `x_(0)+v_(0)SQRT((m)/(K))` |
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| 17. |
Figure shows the orientation of two vectors u and v in the XY plane If u=ahat(i)+bhat(j) and v = phat(i)+qhat(j) which of the following is correct? |
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Answer» <P>a and p ar epositive while b and Q are NEGATIVE. |
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| 18. |
A particle executes simple harmonic motion with frequency f. The frequency of its potential and kinetic energy is……… |
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Answer» `(f)/(2)` |
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| 19. |
In damped oscillations, the amplitude of oscillation is reduced to one - third of its initial value a_(0)at the end of 100 oscillations. When the oscillator completes 200 oscillations, the amplitude must be |
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Answer» `(a_(0))/(2)` |
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| 20. |
An iron bar of length L cross sectional A and young modulus Y is pulled by a force from ends so as to produce an elongation l . Which of the following statements is correct ? |
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Answer» `lprop(l/L)` |
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| 21. |
Given below are densities of some solids and liquids. Give rough estimates of the size of their atoms : [Hint : Assume the atoms to be 'tightly packed' in a solid or liquid phase, and use the known value of Avogadro's number. You should, however, not take the actual numbers you obtain for various atomic sizes too literally. Because of the crudeness of the tight packing approximation, the results only indicate that atomic sizes are in the range of a few Å]. |
| Answer» Solution :CARBON[1.29 Å ], Gold [1.59 Å], LIQUID NITROGEN [1.77 Å ], Lithium [ 1.73 Å ], Liquid FLUORINE[1.88 Å] | |
| 22. |
A man running has half the kinetic energy of a boy of half his mass. The man speeds up by 1 m/s and then has kinetic energy as that of the boy. What were the original speeds of man and the boy ? |
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Answer» `sqrt(2)m//s : 2sqrt(2) m//s` THEREFORE, mass of man is 2m. As KE of man `= 1/2 KE` of boy `:. 1/2 (2m) u^2 = 1/2 XX 1/2 m u.^2` or `u^2 = (u.^(2))/(4) or u = (u.)/(2)` When man speeds up by 1 m/s. KE of man = KE of boy `:. 1/2 (2m) (u + 1)^2 = 1/2 m u.^(2) = 1/2 m (2u)^2 ""` (USING (i)) or `(u +1)^2 = 2u^2 or u + 1 = sqrt(2) u` or `u = 1/(sqrt(2) - 1) = (sqrt(2) + 1)/((sqrt(2) - 1)(sqrt(2) + 1)) = (sqrt(2) + 1) m//s` `:. u. = 2u = 2(sqrt(2) + 1) m//s` . |
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| 23. |
A micron is related to centimetre as |
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Answer» `1 MICRON = 10^-8 CM` |
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| 24. |
A force 'F' acts on an object and moves through a distance x. What is the work done by the force to move the object from x=0 to x=6 m …………. |
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Answer» 12J = Area of square + Area of triangle = 9+4.5 W= 13.5J |
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| 25. |
Mention the values of pressure and volume coefficients of a gas. |
| Answer» SOLUTION :`alpha=beta=1/273//^(@)C` | |
| 26. |
State whether any physical quantity having magnitude and direction is a vector ? |
| Answer» SOLUTION :All physical quantities with MAGNITUDE and direction are not VECTORS. To be a vector, the physical quantity must obey the rules of vector addition. For example, FLOW of current is not a vector quantity though it has both magnitude and direction. | |
| 27. |
The industrial revolution in England of and Western Europe more then two centuries ago was triggered by some key scientific and techological advances. What wer these advances ? |
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Answer» SOLUTION :Industrial revolution in England and Western Europe in 1750 A.D. was triggered by some key scientific and techological advances. Development of steam engine, BLAST furnace (which converts low grade iron into steel) and COTTON gin(which separtes the SEEDS from cotton three hundred TIMES faster then by hand) and power loom are some of the examples. |
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| 28. |
Magnetic field exists in a space and given as B=-(B_(0))/(a)yhatK, where B_(0) and a are constants. A wire PQ, having current I lies inside the magnetic field. If co-ordinates of P and Q are as given, then find the force acting on the wire as given in Table-2. Match the two Table. |
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Answer» |
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| 29. |
Temperature of 1 mole of an ideal gas is increased from 300 k to 310 k under isochoric process. Heat supplied to the gas in this process is Q=25 R, where R= universal gas constant. What amount of work has to be done by the gas if temperature of the gas decrease from 310 K to 300 K adiabatically? |
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Answer» Solution :`DELTA Q = nC_(V)Delta T` ` :. 25R=(1) (C_(v)) (310-300) or C_(v) = 5/2 R` i.e., gas is DIATOMIC or `gamma=1.4` Now work done in adiabatic process `W=(nR(T_(1)-T_(2)))/(gamma-1)=((1)(R)(310-300))/(1.4-1)=25R` |
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| 30. |
Does the radius of gyration depend upon the speed of rotation of the body? |
| Answer» SOLUTION :No, it DEPENDS only on the DISTRIBUTION of MASS of the BODY. | |
| 31. |
State in the following cases, whether the motion is one ,two (or) three dimensional .A carom coin rebounding from the side of the board . |
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Answer» |
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| 32. |
What is meant by perfectly inelastic collision? |
| Answer» Solution :In a perfectly inelastic or completely inelastic COLLISION, the OBJECTS STICK together permanently after collision such that they move with common VELOCITY. | |
| 33. |
Show that the approaches frequency f' of a source of sound moving with a speedv_(s) towards a stationary receiver iff'= (fc)/(c - v_(s)), where c is the velocity of sound and fis the frequency . |
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Answer» Solution :If the source of SOUND approaches the stationary listener with velocity ` v_(s) ` , the number of sound waves F produced per second OCCUPY the distance ` c- v_(s)`. ` therefore ` Apparent wavelength , ` lambda. = (c- v_(s))/(f)` So, apparent frequency , f. = (c) /(lambda.) = (fc)/(c-v_(s))` |
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| 34. |
The elongation of a spring of length L and of negligible mass due to a force is x. The s[ring is cut into two pieces of length in ratio 1:n. The ratio of the respective spring constants is |
| Answer» ANSWER :A | |
| 35. |
If the work done in blowing a soa bubble of volume 'v' is w, then the work done in blowing a soap bubble of volume '2v' is |
| Answer» Answer :D | |
| 36. |
(A) : When a girl sitting on a swing stands up, the periodic time of the swing will decrease. (R): In standing position of girl, the length of the swing will increase. |
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Answer» Both 'A' and 'R' are ture and 'R' is the correct explanation of 'A' |
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| 37. |
A block of mass .M. is lowered with the help of a rope of negli8gible mass through a distance .d. with an acceleration of (g)/(3). Work done by the rope on the block is |
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Answer» `(2Mgd)/(3)` |
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| 38. |
In the expression for alpha, if the temperatures are expressed on Kelvin scale does it give the correct value of alpha ? |
| Answer» SOLUTION :No. The TEMPERATURE are to be taken onn CELSIUS SCALE only. | |
| 39. |
Distance between the centres of two stars is 10a. The masses of these stars are M and 16M and their radii a and 2a , respectively.A body of mass m is fired straight from the surface of the larger star towards the smaller star. What should its minimum initial speed to reach the subject of the smaller star? Obtain the expression in terms of G,M and a. |
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Answer» Solution :The distance x (from the smaller planet) where the gravitational pull of two planet.s balance each other will be given by `(-GMm)/x^2=(-G(16M)m)/((10x-x)^2)` i.e., so the body will reach the smaller planet due to planet.s gravitational field if it has SUFFICIENT energy to cross the point B (x=2a) , i.e `1/2"m"upsilon^2gtm(V_B-V_s)` but `V_(s)=-[(16Gm)/(2a)+(GM)/((10-2a))]=-(65Gm)/(8A)`  and `V_(B)=-[(16GM)/(8a)+(GM)/(2a)]=-(20GM)/(8a)` so `1/2"m"upsilon^(2) gt m [(65GM)/(8a)-(20GM)/(8a)]` i.e `upsilon_("min")=3/2sqrt((5GM)/a)` |
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| 40. |
Which oneof the following statement is incorrect statement |
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Answer» CONCURRENT forces act at a COMMON POINT |
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| 41. |
Pressure, P = |
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Answer» `(1)/(3)MBAR(V^(2))` |
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| 42. |
A drop of radius 1 mm is sprayed into 1000 droplets of same size. If surface tension of the liquid is 40 dyne cm^(-1), the amount of work done in the process is |
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Answer» `4.53erg ` |
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| 43. |
A body is moving in a room with velocity 20 m"/"s perpendicular to the walls separated by 5 meter. There is no friction and collision with walls is elastic. The motion of body………. |
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Answer» is non-PERIODIC |
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| 44. |
What do you mean by multiplication of a vector by a real number ? |
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Answer» Solution :A vector `VEC(A) ` MULTIPLIED by a scalar`lambda`RESULTS in another vectors , `lambda vec(A)`. Eg:FORCE `vec(F) = mvec(a)`. Here mass 'm' is a scalar . `vec(a)`is the ACCELERATION Because 'm' is alwaysa positive scalar . The direction of force is always in the direction of accelereation . |
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| 45. |
Find the centre of mass of the CO molecule. .Given that the atoms are 1.13 xx 10^(-10) m apart and the ratio of the masses of the two atoms m_(0)//m_( c) = 1.33 |
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Answer» |
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| 46. |
Two blocks of mass 4kg and 6kg are connected by a string as shown in the figure . They are initially at rest on the floor . Calculate their acceleration when a force of (a) 50N (b) 100N is applied on the pulley. |
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Answer» Solution :Case (i): FORCE on 6kg and 4kg object` =F/2=25N`. The APPLIED froce in each block is less than the WEIGHT of each block . So the blocks will not move  Case (ii): Force on each block `=(100)/2=50N`. The 6kg block will not move because applied force is less than its weight . On 4kg mass Resutant force = mass X acceleration `50-40=a ,10=4a ,a=2.5 m//s^(2)` |
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| 47. |
The minimum speed with which a body must be thrown to reach a height R"/"4 above the surface of the earth is (R to Radius of the earth) |
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Answer» `SQRT((gR)/(2))` |
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| 48. |
For a reversible process, necessary condition is |
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Answer» In the whole cycle of the system, the LOSS of any type of HEAT energy should be zero |
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| 49. |
A vacuum flask contains 0.4 kg liquid paraffin whose temperature can be increased at the rate of 1^(@)C per minute usingan immersion heater of power 12.3 W. When a heater of 19.2 W is used to heat 0.5 kg of liquid paraffin, in the same flask, the rate of rise temperature is 1.2^(@)C per minute. What is the thermal capacity of the material of the flask? |
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Answer» `"17.67 CAL".^(@)C^(-1)` |
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| 50. |
(A): When a body is projected from the surface of the earth with a velocity greater than the escape velocity, its total mechanical energy is negative. (R) : The body is not under the influence of the earth |
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Answer» Both .A. and .R. are TRUE and .R. is the CORRECT EXPLANATION of .A. |
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