1. UPSEEPAST PAPERSPHYSICS - UNSOLVED PAPER - 2006

2. SECTION Single Correct Answer Type There are five parts in this question. Four choices are given for each part and one of them iscorrect. Indicate you choice of the correct answer for each part in your answer-book bywriting the letter (a), (b), (c) or (d) whichever is appropriate 3. 01 Problem Which of the following is true for rays coming from infinity ? a. Two images are formed b. Continuous image if formed between focal points of upper and lowerlens c. One image is formed d. None of the above 4. 02 Problem What is dimensional formula of thermal conductivity ? a. [MLT-1 - 1] b. [MLT-3 -1] c. [M2LT-3 - 2] d. [ML2T -2 ] 5. 03 Problem A block C of mass m is moving with velocity v0 and collides elastically with block A of mass m and connected to another block A of mass m and connected to another block B of mass 2 m through spring constant k, what is k if x0 is compression of spring when velocity of A and B is same ?2 a. mv0 2x02mv0 b.22 x0 23 mv0 c.22 x0 22 mv0 d.23 x0 6. 04 Problem A bullet of mass 20 g and moving with 600 m/s collides with a block of mass 4 kg hanging with the string. What is velocity of bullet when it come out of block, if block rises to height 0.2 m after collision ? a. 200 m/s b. 150 m/s c. 400 m/s d. 300 m/s 7. 05 Problem What is moment of inertia in terms of angular momentum(L) and kinetic energy (K) ? a. L2KL2 b.2K L c.2K 2 L d.2K 8. 06 Problem A disc of mass 2 kg and radius 0.3 is rotating with angular velocity 30 rad/s. What is angular velocity, if a mass of 0.25 kg is put on periphery of the disc ? a. 24 rad/s b. 36 rad/s c. 15 rad/s d. 26 rad/s 9. 07 Problem If a body is raised from the surface of the earth upto height R, what is the change in potential energy ? a. mgR b. 3/2 mgRmgR c. 2mgR d. 4 10. 08 Problem A piston of cross-section area A is fitted in cylinder in which gas of volume V at pressure P is enclosed. Gas obeys Boyles law, what is angular frequency if piston is displaced slightly ?Ag a.VAg b. 2 V c. 2Ag V d. 3AgV 11. 09 Problem Carbon, silicon and germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by (Eg)c, (Eg)Si and (Eg)Ge respectively. Which one of the following relationship is true in their case ? a. (Eg)c > (Eg)Si b. (Eg)c = (Eg)Si c. (Eg)c < (Eg)Gi d. (Eg)c < (Eg)Si 12. 10 Problem A piston fitted in cylindrical pipe is pulled as shown in the figure. A tuning fork is sounded at open end and loudest sound s heard at open length 13 cm, 41 cm and 69 cm, the frequency of tuning fork if velocity of sound is 350 m/s, is : a. 1250 Hz b. 625 Hz c. 417 Hz d. 715 Hz 13. 11 Problem A man is standing on the platform and one train is approaching and another train is gong away with speed of 4 m/s, frequency of sound produced by train is 240 Hz. What will be the no. of beats heard by him per second ? a. 12 b. zero c. 6 d. 3 14. 12 Problem A capacitor having capacitance 1 F with air is filled with two dielectrics as shown. How many times capacitance will increase ? a. 12 b. 6 c. 8/3 d. 3 15. 13 Problem Permanent magnet his properties retentivity and coercivity respectively : a. High-high b. Low-low c. Low-high d. High-low 16. 14 Problem Hydrogen bomb is based upon a. Fission b. Fusion c. Chemical reaction d. Transmutation 17. 15 Problem Six moles of O2 gas is heated from 200C to 350C at constant volume. If specific heat capacity at constant pressure is 8 cal/mol-K and R = 8.31 J/mol-K, what is change in internal energy of gas ? a. 180 cal b. 300 cal c. 360 cal d. 540 cal 18. 16 Problem In Carnot engine efficiency is 40% at hot reservoir temperature T. For efficiency 50% what will be temperature of hot reservoir ?T a.52T b. 5 c. 6T6T d.5 19. 17 Problem A ball of mass 2 kg moving with velocity 3 m/s, collides with spring of natural length 2 m and force constant 144 N/m. What willl be length of compressed spring ? a. 2 m b. 1.5 m c. 1m d. 0.5 m 20. 18 Problem A proton moving horizontally downward enters in a magnetic field pointing towards north. In which direction proton will deflect ? a. East b. West c. North d. South 21. 19 Problem Induced emf in the coil depends upon : a. Conductivity of coil b. Amount of flux c. Rate of change of linked flux d. Resistance of coil 22. 20 Problem With in depletion regions of p-n junction diode : a. p-side is positive and n-side is negative b. p-side is negative and n-side is positive c. both sides are positive or both negative d. both sides are neutral 23. 21 Problem 27 small drops each having charge q and radius r coalesce to from big drop, how many times charge and capacitance will become ? a. 3, 27 b. 27, 3 c. 27, 27 d. 3, 3 24. 22 Problem X-rays are used in determining the molecular structure of crystalline because its : a. Energy is high b. It can penetrate the material c. Its wavelength is comparable to interatomic distance d. Its frequency is low 25. 23 Problem In a radioactive material the activity at time t1 is R1 and at a later time t2, it isE R2. If the decay constant of the material is , then :B a. R1 = R2 e (t 1 t2 ) b. R1 = R2 e(t1 t2 ) c. R1 = R2 (t2 / t1) d. R1 = R2 26. 24 Problem A steel ball of mass 5g is thrown downward with velocity 10 m/s from height 19.5 m. It penetrates sand by 50 cm. The change in mechanical energy will be : (g = 10 m/s2) a. 1 J b. 1.25 J c. 1.5 J d. 1.75 J 27. 25 Problem Two identical springs are connected in series and parallel as shown in the figure. If fs and fp are frequencies of series and parallel arrangements, what is fs ? fp a. 1 : 2 b. 2 : 1 c. 1 : 3 d. 3 : 1 28. 26 Problem Light of frequency v falls on material of threshold frequency v0. Maximum kinetic energy of emitted electron is proportional to : a. v - v0 b. V c.v v0 d. v0 29. 27 Problem A wave equation is given by 1 x 1 where, x is in cam and t in y 4 sin 5 9 6 sec. Which of the following is true ? = 18 cm v = 4 m/s a = 0.4 m f = 50 Hz 30. 28 Problem A light moves from denser to rarer medium. Which of the following is correct ? a. Energy increases b. Frequency increases c. Phase changes by 900 d. Velocity increases 31. 29 Problem A small disc of radius 2 cm is cut from a disc of radius 6 cm. If the distance between their centers is 3.2 cm, what is the shift in the centre of mass of the disc ? a. 0.4 cm b. 2.4 cm c. 1.8 cm d. 1.2 cm 32. 30 Problem Which one of the following statements is true ? a. Both light and sound waves in air are transverse b. The sound waves in air are longitudinal while the light waves aretransverse c. Both light and sound waves in air are longitudinal d. Both light and sound waves can travel in vacuum 33. 31 Problem What is not true for equipotential surface for uniform electric field ? Equipotential surface is flat Equipotential surface is spherical Electric lines are perpendicular to equipotential surface Work done is zero 34. 32 Problem Two copper wires of lengths l and 2l have radil r and 2r respectively. What is raito of their specific resistances ? a. 1 : 2 b. 2 : 1 c. 1 : 1 d. 1 : 3 35. 33 Problem A metro trains strats from rest and in five seconds achieves 108 km/h. After that it moves with constant velocity and comes to rest after traveling 45 m with uniform retardation. If total distance traveled is 395 m, find total time of traveling. a. 12.2 s b. 15.3 s c. 9 s d. 17.2 s 36. 34 Problem The radius of germanium (Ge) nuclide is measured to be twice the radius of Be. The number of nucleons in Ge are : a. 73 b. 74 c. 75 d. 72 37. 35 Problem a1t a2t 2 The displacement of particle is given by x a0 What is its2 3 acceleration ?2a2 a. 3 b. - 2a2 3 c. a2 d. zero 38. 36 Problem If | A x B | 3 A B, then the value of | A B| is : a. (A2 + B2 + AB)1/2 1/2 2 2AB b.A B 3 c. A + B d. (A2 + B2 + 3 AB)1/2 39. 37 Problem Pressure of an ideal gas is increased by keeping temperature constant. What is the effect on kinetic energy of molecule ? a. Increase b. Decrease c. No change d. Cant be determined 40. 38 Problem Two spheres of same size, one of mass 2 kg and another of mass 4 kg, are dropped simultaneously from the top of Qutab Minar (height = 72m). when they are 1 m above the ground, the two spheres have the same : a. Momentum b. Kinetic energy c. Potential energy d. Acceleration 41. 39 Problem The moment of inertia of a rod about an axis through its centre and perpendicular to it is1 ML2 (where, M is the mass and L, the length of the12 rod). The rod is bent in the middle so that the two halves make an angle of 600. the moment of inertia of the bent rod about the same axis would be :1 a. 48 ML2 1 b. 12 ML21 c. 24 ML22 d. ML8 3 42. 40 Problem A boat at anchor is rocked by waves whose crests are 100 m apart and velocity is 25 m/s. the boat bounces up once in every : a. 2500 s b. 75 s c. 4 s d. 0.25 s 43. 41 Problem By sucking through a straw, a student can reduce the pressure in his lungs to 750 mm of Hg (density = 13.6 g/cm3). Using the straw, he can drink water from a glass upto a maximum depth of : a. 10 cm b. 75 cm c. 13.6 cm d. 1.36 cm 44. 42 Problem Two parallel large thin metal sheets have equal surface charge densities ( = 26.4 x 10-12 C/m2) of opposite sings. The electric field between these sheets is : a. 1.5 N/C b. 1.5 x 10-10 N/C c. 3 N/C d. 3 x 10-10 N/C 45. 43 Problem A wire mesh consisting of every small squares is viewed at a distance of 8 cm through a magnifying converging lens of focal length 10 cm, kept close to the eye. The magnification produced by the lens is : a. 5 b. 8 c. 10 d. 20 46. 44 Problem Hard X-rays for the study of fractures in bones should have a minimum wavelength of 10-11 m. the accelerating voltage for electrons in X-ray machine should be : a. < 124 kV b. > 124 kV c. between 60 kV and 70 kV d. = 100 kV 47. 45 Problem A lens is made of flint glass (refractive index = 1.5). When the lens is immersed in a liquid of refractive index 1.25, the focal length : a. Increases by a factor of 1.25 b. Increases by a factor of 2.5 c. Increases by a factor of 1.2 d. Decreases by a factor of 1.2 48. 46 Problem The voltage of clouds is 4 x 106 V with respect to ground. In a lightning strike lasing 100 ms, a charge of 4 C is delivered to the ground. The power of lightning strike is : a. 160 MW b. 80 MW c. 20 MW d. 500 kW 49. 47 Problem For inelastic collision between two spherical rigid bodies : a. The total kinetic energy is conserved b. The total mechanical energy is not conserved c. The linear momentum is not conserved d. The linear momentum is conserved 50. 48 Problem Which of the following diagrams represent the variation of electric field vector with time for a circularly polarized light ? a. b. c. d. 51. 49 Problem The operation of a nuclear reactor is said to be critical, if the multiplication factor (k) has a value : a. 1 b. 1.5 c. 2.1 d. 2.5 52. 50 Problem The circuit given below represents which of the logic operations ? a. AND b. NOT c. OR d. NOR 53. 51 Problem Three objects coloured black, gray and white can with stand hostile conditions at 28000C. These objects are thrown into furnace where each of them attains a temperature of 20000C. Which object will glow brightest ? a. The white object b. The black object c. All glow with equal brightness d. Gray object 54. 52 Problem Two balloons are filled, one with pure He gas and the other by air, respectively. If the pressure and temperature of these balloons are same then the number of molecules per unit volume is : a. More in the He filled balloon b. Same in both balloons c. More in air filled balloon d. In the ratio of 1 : 4 55. 53 Problem Flash light equipped with a new set of batteries, produces bright whit light. As the batteries wear out : a. The light intensity gets reduced with no change in its colour b. Light colour changes first to yellow and then red with no change inintensity c. It stops working suddenly while giving white light d. Colour changes to red and also intensity gets reduced 56. 54 Problem The spatial distribution of the electric field due to charge (A, B) is shown in figure. Which one of the following statements is correct ? a. A is + ve and B- ve, |A| > |B| b. A is - ve and B + ve, |A| > |B| c. Both are + ve but A > B d. Both are - ve but A > B 57. 55 Problem If a street light of mass M is suspended from the end of a uniform rod of length L in different possible patterns as shown in figure, then : a. Pattern A is more sturdy b. Pattern B is more sturdy c. Pattern C is more sturdy d. All will have same sturdiness 58. 56 Problem238 92 U has 92 protons and 238 nucleons. It decays by emitting an alpha particle and becomes :234 a.92U b. 234 Th 90235 c.92 U d. 237 Np 92 59. 57 Problem The fossil bone has a 14C : 12C ratio, which is 1 of that in a living animal 16 bone. If the half-life of 14C is 5730 years, then the age of the fossil bone is : a. 11460 years b. 17190 years c. 22920 years d. 45840 years 60. 58 Problem Two tuning forks P and Q when set vibrating, give 4 beats per second. If a prong of the fork P is filled, the beats are reduced to 2/s. What is frequency of P, if that of Q is 250 Hz a. 246 Hz b. 250 Hz c. 254 Hz d. 252 Hz 61. 59 Problem If alpha, beta and gamma rays carry same momentum, which has the longest wavelength a. Alpha rays b. Beta rays c. Gamma rays d. None, all have same wavelength 62. 60 Problem When you make ice cubes, the entropy of water : a. Does not change b. Increases c. Decreases d. May either increase or decreases depending on the process used 63. 61 Problem A light emitting diode (LED) has a voltage drop of 2 V across it and passes current of 10 mA. When it operates with a 6 V battery through a limiting resistor R, the value of R is : a. 40 k b. 4 k c. 200 k d. 400 64. 62 Problem The minimum potential difference between the base and emitter required to switch a sillcon transistor ON is approximately: a. 1 V b. 3 V c. 5 V d. 4.2 V 65. 63 Problem 2 Given that : y A sin (ct x ) where, y and x are measured in metres. Which of the following statements is true ? a. The unit of is same as that of x and A b. The unit of is same as that of x but not of A 2 c. The unit of c is same as that of 2 d. The unit of (ct - x) is same as that of 66. 64 Problem A projectile is thrown in the upward direction making an angle of 600 with the horizontal direction with a velocity of 147 ms-1. Then the time after which is inclination with the horizontal is 450, is : a. 15 s b. 10.98 s c. 5.49 s d. 2.745 s 67. 65 Problem A wire 3m in length and 1 mm in diameter at 300C is kept in a low temperature at 1700C and is stretched by hanging a weight of 10 kg at one end. The change in length of the wire is : [Y = 2 x 1011 N/m2, g = 10 m/s2 and = 1.2 x 10-5/0C] a. 5.2 mm b. 2.5 mm c. 52 mm d. 25 mm 68. 66 Problem A tank is filled with water of density 1g per cm3 and oil of density 0.9 g per cm3. The height of water layer is 100 cm and of the oil layer is 400 cm. If g = 980 cm/s2, then the velocity of efflux from an opening in the bottom of the tank is : a.900 x 980cm/s b.1000 x 980 cm/s c. 920 x 980 cm/s d. 950 x 980 cm/s 69. 67 Problem an engineer claims to have made an engine delivering 10 kW power with fuel consumption of 1 g/s. The calorific value of fuel is 2 kcal/g. This claim is : a. valid b. invalid c. depends on engine design d. dependent on load 70. 68 Problem Two concentric spheres of radii R and r have similar charges with equal surface densities ( ) What is the electric potential at their common centre ? a. / 0 b. 0 (R - r) c. (R + r)0 d. none of these 71. 69 Problem In the condenser shown in the circuit is charged to 5V and left in the circuit, in 12s the charge on the condenser will become : a. 10 C e e b. 10 C10 c. e2 Ce2 d. 10 C (e = 2.718) 72. 70 Problem Two cells, having the same emf, are connected in series through an external resistance R Cells have internal resistance r1 and r2 (r1 > r2) respectively. When the circuit is closed, the potential difference across the first cell is zero. The value of R is : a. r1 r2 b. r1 r2 2 c. r1 r2 2 d. r1 + r2 73. 71 Problem Flemings left and right hand rules are used in : a. DC motor and AC generator b. DC generator and AC motor c. DC motor and DC generator d. Both rules are same, any one can be used 74. 72 Problem A long hollow copper tube carries a current I. Then which of the following will be true ? a. The magnetic field B will be zero at all points inside the tube b. The magnetic field B will be zero only at points on the axis of the tube c. The magnetic field B will be maximum at points on the axis of the tube d. The magnetic field will be zero at any point outside the tube 75. 73 Problem A battery has an emf of 15 V and internal resistance of 1 . Is the terminal to terminal potential difference less than, equal to or greater than 15 V if the current in the battery is (1) from negative to positive terminal, (2) from positive to negative terminal (3) zero current ? a. Less, greater, equal b. Less, less, equal c. Greater, greater, equal d. Greater, less, equal 76. 74 Problem An inductance L and a resistance R are connected in series with a battery of emf .The maximum rate at which the energy is stored in the magnetic field is : a. 24R2 b.2R2R c. 4R d. 77. 75 Problem Cause of heat production in a current carrying conductor is : a. Collisions of free electrons with one another b. High drift speed of free electrons c. Collisions of free electrons with atoms or ions of the conductor d. High resistance value 78. FOR SOLUTIONS VISIT WWW.VASISTA.NET