Science-Class-11 Physics and Chemistry DPP Talent Search Examinations

Physics & Chemistry-XI 1. A block A slides over an another block B which is placed over a smooth inclined plane as shown in figure. The coefficient of friction between the two blocks A and B is µ. Mass of block B is two times the mass of block A. The acceleration of the centre of mass of two blocks is Fixed  g sin  g cos  (a) g sin  (b) 3 g sin  (c) 3 2g sin   g cos  (d) 3 F 2. A force F acts tangentially at the highest point of a ring of mass M kept on a rough horizontal plane as shown. If the CM sphere rolls without slipping, the acceleration of centre of mass of the ring (a) 12 F 5 M (b) 15 F 7 M (c) 7 F 10 M F (d) M Comprehension s As shown in the figure, an objects of mass M1 is suspended from a massless string s3 s1 M1 1m and M2 is held stationary. Masses M1 and P2 M2 are connected to fixed frictionless 1m s2 30° 1 pivots P1 and P2 by strings s1 and s2. At M 60° time t = 0 the string s3 is cut 2 3. Find the time t1 after which the string s1becomes taut again, the height h through which the mass M1 falls freely and the speed v1 of the mass M1 just after the string s1 is taut. (a) 1 5 s, m, 10 m/ sec 2 (b) 1 s,1m, 15 m/sec 5 (c) 1 s,1m, 10 m/ sec 5 (d) none of these - : Rough Space : - [2] Physics & Chemistry-XI 4. At time t = t1, M2 is released with the same speed v1 in a direction perpendicular to the string in anticlockwise sense. Find the velocity of both the masses just before they collide. (a) 22 m/sec (b) 30 m/sec (c) 19 m/sec (d) 16 m/sec 5. Will the string s1 be taut immediately after the collision? (a) yes (b) no (c) con’t say (d) none of these 6. If M1 = M2 and the collision is perfectly elastic, what is the maximum height attained by the mass M1 relative to the point of collision. (a) 1.5 m (b) 0.75 m (c) 1 m (d) 0.475 m 7. A container is filled with the liquid is at rest on friction less surface. Liquid starts leaking from bottom of the container, motion of container is, (a) it remains at rest (b) it moves rightward with acceleration (c) it moves leftward with acceleration (d) it undergoes oscillatory motion 8. A liquid is filled in the container as shown in the figure, what is the height between edge and centre of the meniscus given, surface tension h T = 0.073 N/m (a) 3.8 mm (b) 2.8 mm (c) 1.2 mm (d) none of these 9. A cubical block of side ‘a’ is inside the liquid filled in a container having acceleration x m/sec2 horizontally. What is thrust on the block by liquid if density of liquid is  and that of block is /2 (a) a3g (b) a3 g 2  x2 (c) 2a3 x2  g2 (d) none of these 10. A pencil of length l is placed vertically on rough horizontal surface. It is slightly disturbed from this position and allowed to fall. Minimum coefficient of friction required to avoid shading of pencil. (a) continuously increases (b) continuously decreases (c) first increases than decreases (d) none of these - : Rough Space : - [3] Physics & Chemistry-XI 11. A block of weight W produces an extension of 9 cm when it is hung by an elastic spring of length 60 cm and is in equilibrium. The spring is cut m into two parts, one of length 40 cm and the other of length 20 cm. The same load W hangs in equilibrium supported by both parts as shown in the figure. The extension in cm now is (a) 9 (b) 6 (c) 3 (d) 2 W W 12. A container having a hole near the bottom is free to move on a horizontal surface. As the liquid comes out, the container moves in backward direction with an acceleration  and finally acquires a velocity v( when all the liquid has drained out). Neglect the mass of container. The correct option out of the following is (a) Only v depends on h (b) Only  depends on h (c) Both v and  depend on h (d) Neither v nor  depends on h 13. A hemisphere of mass 4 m is free to slide with its base on a smooth horizontal table. A particle of mass m is placed on the top of the hemisphere. The hemisphere has now acquired a velocity v. Then the angular velocity of the particle relative to the hemisphere at an angular distance  is (radius of hemisphere is ‘a’) (a) 3 v a cos  (b) 4 v a cos  (c) 5 v a cos  (d) 2 v a cos  14. Two bodies having masses m and 3 m and velocities u1 and u2 collide elastically (m1  m2). Their relative velocity after collision is (a) 0 (b) u1 + u2 (c) u1 – u2 (d) (u1 + u2)/2 - : Rough Space : - [4] Physics & Chemistry-XI 15. A source S emits electromagnetic wave which are detected by the detector D kept at a distance of d/4 from the source. The waves directly received from S and reflected by a layer d above the ground are found to be in phase. If the layer moves up by a distance h = 0.01 d, the interfering waves are once again in phase. The wavelength of the waves from the source is about (a) 0.04 d (b) 0.08 d (c) 0.02 d (d) 0.01 d t   x  16. Two elastic waves represented respectively by the equations y = a sin   t   x  l  and y2 = 2a sin    l  superimpose at a point A to produce an maximum intensity and at point B to produced minimum intensity. Which of the following statement will be true in respect of this superposition? (a) The intensity maximum at A will be (measured in terms of the intensity of the first wave as unit) 9 units (b) The amplitude of the superposed wave at the point B will have a magnitude 3a (c) At point B amplitude is zero (d) Particles in adjacent loop will vibrate out of phase 17. A particle moves in x-y plane with velocity V = ai + btj. At the instant t = tangential, normal and total accelerations are a 3 . The magnitude of b (a) 3 b, b 2 2 and b respectively (b) b , b 2 2 and b respectively (c) b 2 , b 2 and b respectively (d) none of these - : Rough Space : - [5] Physics & Chemistry-XI 18. The coordinates of a particle moving in a plane are given by x = 4 cos 10t, and y = 3 sin 10t. (a) Then the equation of the path of the particle is ellipse (b) The angle between position vector and velocity is /2 at time t = /20 (c) Acceleration is directed toward origin (d) all of these 19. A particle of mass 5 kg moving in the X-Y plane has its potential energy given by U = (–7x + 24y) Joule. The particle is initially at origin and has a velocity u = (14.4i + 4.2j) m/s (a) the particle has speed 25 m/s at t = 4 sec (b) the particle has an acceleration 5 m/s2 (c) the acceleration of particle is normal to its initial velocity (d) all of these 20. An object of specific gravity  is hung from a thin steel wire. The fundamental frequency for transverse standing waves in the wire is f Hz. The object is immersed in water so that one half of its volume is submerged. The new fundamental frequency in Hz is  2  1 1/ 2  2 1/ 2  2   2  1  (a) f  2  (b) f   2  1 (c) f   2  1 (d) f  2          21. The distance between two points is d and temperature between them varies linearly from T1 to T2. What will be the time taken by sound waves to travel this distance if velocity of sound propagation in air varies as v =  T . d T1 2d T2 2d T1 d T2 (a) (T2  T1 ) (b) (T2  T1 ) (c) (T2  T1 ) (d) (T2  T1 ) - : Rough Space : - [6] Physics & Chemistry-XI 22. A forced oscillator is acted upon by a force F = F0 sin t. The amplitude of the oscillation is given by 55 2  36  9 , what is the resonant angular frequency? (a) 2 (b) 9 (c) 18 (d) 36 23. The ends of a stretched wire of length L are fixed at x = 0 and x = L. In one experiment, the displacement of the wire is y1 = A sin (x/L) sin t and energy is E1 and in another experiment its displacement is y2 = A sin (2x/L) sin 2 t and energy is E2. Then (a) E1 > E2 (b) E1 < E2 (c) E1 may be greater or less than E2 (d) none of these 24. The equation of a state of a gas is given by p(V – b) = nRT. If 1 mole of a gas is isothermally expanded from volume V to 2V, the work done during the process is (a) RT ln 2 V b V b (b) RT ln V b V (c) RT ln V b 2 V b (d) RT ln V V b 25. A metallic sphere having radius 0.08 m and mass m = 10 kg is heated to a temperature of 227°C and suspended inside a box whose walls are at a temperature of 27°C. The maximum rate at which its temperature will fall is: (Take e = 1, Stefan’s constant  = 5.8 × 10–8 Wm–2 K–4 and specific heat of the metal s = 90 cal/kg/ deg J = 4.2 Joules/Calorie) (a) 0.055° C/sec (b) 0.066° C/sec (c) 0.044° C/sec (d) 0.03° C/sec 26. In a process the pressure of a gas is inversely proportional to the square of the volume. If temperature of the gas increases, then work done by the gas (a) is positive (b) is negative (c) is zero (d) either of these - : Rough Space : - [7] Physics & Chemistry-XI 27. System is shown in the figure. Assume that cylinder remains in contact with the two wedges. The velocity of cylinder is Cylinder (a) 19  4 3 u m/s (b) 2 13u m/s 2 u m/s 30° 2u m/s 30° (c) 3u m/s (d) 7u m/s 28. A cone of radius R and height H, is hanging inside a liquid of density  by means of a string as shown in the figure. The force due to the liquid acting on the slant surface of the cone is H (a) gHR2 (b) HR2 R (c) 4 gHR2 (d) 3 2 gHR2 3 29. Logarithms of readings of pressure and volume for an ideal gas were plotted on a graph as shown in the figure. By measuring the gradient, it can be shown that the gas may be (a) monoatomic and undergoing an adiabatic change (b) monoatomic and undergoing an isothermal change (c) diatomic and undergoing an adiabatic change (d) triatomic and undergoing an isothermal change 30. Two objects are moving as shown in the figure what is their 2.38 2.30 2.20 2.10 1.10 1.20 1.30 log V(dm3) total angular momentum about O. (a) 14 kg ms–1 (b) 7.29 kg m2s–1 (c) 21.3 kg m2s–1 (d) 6.71 kg m2s–1 2.7 kg 1.5 m O 1.8 ms–1 2.4 m 3.5 ms–1 1.67 kg - : Rough Space : - [8] Physics & Chemistry-XI 31. A mixture containing 0.05 mole of K2Cr2O7 and 0.02 mole of KMnO4 was treated with excess of KI in acidic medium. The liberated iodine required 1.0 L of Na2S2O3 solution for titration. Concentration of Na2S2O3 solution was (a) 0.40 mol L–1 (b) 0.20 mol L–1 (c) 0.25 mol L–1 (d) 0.30 mol L–1 32. If a g is the mass of NaHC2O4 required to neutralize 100 mL of 0.2 M NaOH and b g that required to reduce 100 mL of 0.02 M KMnO4 in acidic medium, then: (a) a = b (b) 2a = b (c) a = 2b (d) a = 4 b 33. A mineral consists of an equimolar mixture of the carbonates of two bivalent metals. One metal is present to the extent of 12.5% by weight. 2.8 g of the mineral on heating lost 1.32 g of CO2. What is the % by weight of the other metal? (a) 87.5 (b) 35.71 (c) 65.11 (d) 23.21 34. A beam of specific kind of particles of velocity 2.1 × 107 m/s is scattered by a gold (Z = 79) nuclei. Find out specific charge (charge/mass) of this particle if the distance of closest approach is 2.5 × 10–14 m. (a) 4.84 × 107 C/g (b) 2.42 × 10–7 C/g (c) 2.42 × 107 C/g (d) 3 × 10–12 C/g 35. The velocity of an e– in excited state of H-atom is 1.093 × 106 m/s. What is the circumference of this orbit? (a) 3.32 × 10–10 m (b) 6.64 × 10–10 m (c) 13.30 × 10–10 m (d) 13.28 × 10–8 m 36. A open flask containing air is heated from 300 K to 500 K. What percentage of air will be escaped to the atmosphere, if pressure is keeping constant? (a) 80 (b) 40 (c) 60 (d) 20 - : Rough Space : - [9] Physics & Chemistry-XI 37. O2 and SO2 gases are filled in ratio of 1 : 3 by mass in a closed container of 3 L at temperature of 27°C. The partial pressure of O2 is 0.60 atm, the molar concentration of SO2 would be (a) 0.36 (b) 0.036 (c) 3.6 (d) 36 38. van der Waals constant b of helium is 24 mL mol–1. Find molecular diameter of helium. (a) 1.335 × 10–10 cm (b) 1.335 × 10–8 cm (c) 2.67 × 10–8 cm (d) 4.34 × 10–8 cm 39. Calculate the final temperature of a monoatomic ideal gas that is compressed reversible and adiabatically from 16 L to 2 L at 300 K (a) 600 K (b) 1044.6 K (c) 1200 K (d) 2400 K 40. Calculate average molar heat capacity at constant volume of gaseous mixture contained 2 mole of each of two ideal gases A (g) and B2(g) (a) R (b) 2R (c) 3R (d) 8R 41. What is the change in entropy when 2.5 mole of water is heated from 27°C to 87°C? Assume that the heat capacity is constant. (Cp,(H2O) = 4.2 J/g-K, ln (1.2) = 0.18) (a) 166.6 J/K (b) 9 J/K (c) 34.02 J/K (d) 1.89 J/K 42. At 27°C and 1 atm pressure, N2O4 is 20% dissociation into NO2. What is the density of equilibrium mixture of N2O4 and NO2 at 27°C and 1 atm? (a) 3.11 g/litre (b) 2.11 g/litre (c) 4.5 g/litre (d) none of these 43. Pure PCl5 is introduced into an evacuated chamber and comes to equilibrium at 247°C and 2.0 atm. The equilibrium gaseous mixture constants 40% chlorine by volume. Calculate Kp at 247°C for the reaction PCl5(g)   PCl3(g) + Cl2(g) (a) 0.625 atm (b) 4 atm (c) 1.6 atm (d) none of these - : Rough Space : - [10] Physics & Chemistry-XI 44. Assume that the decomposition of HNO3 can be represented by the following equation 4HNO3(g)   4NO2(g) + 2H2O(g) + O2(g) and the reaction approaches equilibrium at 400 K temperature and 30 atm pressure. At equilibrium partial pressure of HNO3 is 2 atm. Calculate Kc in (mol/L) at 400 K: (Use : R = 0.08 atm-L/mol-K) (a) 4 (b) 8 (c) 16 (d) 32 45. Kp has the value of 10–6 atm3 and 10–4 atm3 at 298 K and 323 K respectively for the reaction CuSO4. 3H2O (s)   CuSO4(s) + 3H2O(g) DrH° for the reaction is (a) 7.7 kJ/mol (b) –147.41 kJ/mol (c) 147.41 kJ/mol (d) none of these 46. How much water must be added to 300 mL of 0.2 M solution of CH3COOH (Ka = 1.8 × 10–5) for the D.O.I. (a) of the acid to double? (a) 600 mL (b) 900 mL (c) 1200 mL (d) 1500 mL 47. The [H+] of a resulting solution that is 0.01 M acetic acid (Ka = 1.8 × 10–5) and 0.01 M in benzoic acid (Ka = 6.3 × 10–5) (a) 9 × 10–4 (b) 81 × 10–4 (c) 9 × 10–5 (d) 2.8 × 10–3 48. Which of the following statement is/are wrong? (a) van der Waal’s radius of iodine is more than its covalent radius (b) All isoelectronic ions belong to same period of the periodic table (c) I.E.1 of N is higher than that of O while I.E.2 of O is higher than that of N (d) The electron gain enthalpy of N is almost zero while that of P is 74.3 kJ mol–1 - : Rough Space : - [11] Physics & Chemistry-XI 49. Select correct statement (a) Acidic strength of HBr > HCl but reverse is true for their reducing property (b) Basic strength of PH3 > AsH3 but reverse is true for their Bond angle. (c) Dipole moment of CH3Cl > CH3F but reverse is true for their HCH bond angle (d) Ka of fumaric acid is higher than maleic acid but reverse is true for their Ka 50. If CdI2 is pink in colour, the CdCl2 will ‘ ’ coloured. (a) yellow (b) red (c) blue (d) cannot be predicted 51. A solution of a metal ion, when treated with KI, gives a red precipitate which dissolves in an excess of KI to give a colourless solution. Moreover, the solution of the metal ion on treatment with a solution of cobalt (II) thiocyanate gives rise to a deep blue crystalline precipitate. The metal ions is (a) Pb2+ (b) Hg2+ (c) Cu2+ (d) Co2+ 52. Which of the following statement about the sulphate of alkali metal is correct? (a) Except Li2SO4 all sulphate of other alkali metals are soluble in water (b) All sulphate salts of alkali metals except lithium sulphate forms alum. (c) All sulphate salts of alkali metals except lithium sulphate do not decompose at high temperature (d) all of these 53. Which is not true about borax? (a) It is a useful primary standard for titrating against acids (b) One mole of borax can be used as a buffer (c) Aqueous solution of borax can be used as buffer (d) It is made up of two triangular BO3 units and two tetrahedral BO4 units - : Rough Space : - [12] Physics & Chemistry-XI 54. Which is most stable? O O (a) O (b) MeO MeO OMe OMe O O (c) Ph – C – CH2 (d) CH2 = CH– 55. For which of the following molecules µ ¹ 0? Cl CN OH SH I. II. Cl CN III. OH IV. SH (a) only I (b) I and II (c) only III (d) III and IV 56. The correct basic strength order is NH CH3 O . . C CH3 NH O C CH2 NH2 H2N C CH3 I II III IV (a) I > II > IV > III (b) IV > III > II > I (c) III > II > IV > I (d) III > IV > II > I - : Rough Space : - [13] Physics & Chemistry-XI 57. Identify the structure of X H2/Ni X CH3 O O O O O O O3 Zn/H2O CH3 – C – CH – C – H + H – C – H + CH 2 – C – C – CH2 – C – H CH3 CH3 (a) (b) (c) (d) 58. CBr4  P Q, Compound Q is nBuLi Br Br (a) Br Br (b) Br (c) Br (d) Br Br Br Br 59. Which one of the following hexachlorocyclohexane is least reactive and which one is most reactive for E2 reactions with a strong base for dehydrohalogenation. Cl Cl Cl I. II. Cl Cl Cl III. Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl (a) I least and II most (b) II least and I most (c) III least and I most (d) III least and II most - : Rough Space : - [14] Physics & Chemistry-XI 60. CH – C* H – CH – CH  CI2 ,heator Products, CH – C* H – CH – CH 3 2 3 Cl light 3 3 Cl Cl Which statement is incorrect (a) One of the product exist as three stereoisomers (b) Two pair of diastereomers are obtained only (c) Only one meso stereoisomer is obtained (d) Two pair of enantiomers are obtained 🙤🙦🙥🙧 - : Rough Space : - [15]