Vidyamandir ClassesVMC/ 2010 1 BITSAT PRACTICE TEST - 4 BITSAT PRACTICE TEST – 4/2010 (PHYSICS) 1. The relation gives the value of ‘x’ 3 3 a b x c d = . Find the percentage error in ‘x’, if the percentage error in a, b, c, d are 2 , 1 , 3 and 4 % % % % respectively. (A) 8% ± (B) 10% ± (C) 12% ± (D) 14% ± 2. Two forces of magnitudes 3N and 4N are acting on a body. The ratio of magnitude of minimum and maximum resultant force on the body is : (A) 3 / 4 (B) 4/ 3 (C) 1 / 7 (D) None of these 3. A particle is projected at an angle 60° with the horizontal with a speed 10 m/sec. Then latus rectum is (Take g = 10 m/s 2 ) (A) 5 m (B) 15 m (C) 10 m (D) 0 4. A cyclist is moving with a content acceleration of 1.2 m/s 2 on a straight track. A racer is moving on a circular path of radius 150 m at constant speed of 15m/s. Find the magnitude of velocity of racer which is measured by the cyclist has reached a speed of 20 m / s for the position represented in the figure (A) 18.03 m/s (B) 25 m / s (C) 20 m / s (D) 15 m / s 5. For the equilibrium of a body on an inclined plane of inclination 45° . The coefficient of static friction will be : (A) greater than one (B) less than one (C) zero (D) less than zero 6. A solid body rotates about a stationary axis so that its angular velocity depends on the rotational angle o as 0 0 where k e e o e = ÷ and k are positive constants. At the moment t = 0, 0 o = . Find the time dependence of rotation angle. (A) 0 kt k e e ÷ (B) 0 kt e k e ÷ (C) ( ) 0 1 kt e k e ÷ ÷ (D) ( ) 0 1 kt k e e ÷ ÷ Vidyamandir Classes VMC/ 2010 2 BITSAT PRACTICE TEST - 4 7. Two small ball of equal mass are joined by a light rigid rod. If they are released form rest in the position shown and slide on the smooth track in the vertical plane. The speed of balls when A reached B’s position and B is at B' is : (A) 4 m / s (B) 4.21 m / s (C) 2.21 m / s (D) None of these 8. A nucleus moving with a velocity n emits an particle o ÷ . Let the velocities of the particle o ÷ and the remaining nucleus be 1 2 and n n and their masses be m 1 and m 2 , then (A) 1 2 , and n n n must be parallel to each other (B) none of the two of 1 2 , and n n n should be parallel to each other (C) 1 2 n n + must be parallel to n (D) 1 2 1 2 m n m n + must be parallel to n 9. Two boys of masses 10 kg and 8 kg are moving along a vertical rope, the former climbing up with acceleration of 2 m/s 2 while later coming down with uniform velocity of 2 m/s. Then tension in rope at fixed support will be (Taken g = 10 m/s 2 ) (A) 200 N (B) 120 N (C) 180 N (D) 160 N 10. L = Ie formula is : (A) always correct (B) sometimes correct (C) always wrong (D) physically correct but dimensionally wrong 11. The gravitational force in a region is given by E ayi ax j = + Find the work done by gravitational force to shift a point mass m from (0, 0, 0) to (x 0 , y 0 , z 0 ) (A) ma x 0 y 0 z 0 (B) ma x 0 y 0 (C) 0 0 ma x y ÷ (D) zero 12. A satellite is moving on a circular path of radius r around earth has a time period T. If its radius slightly increases by Δr , determine the change in its time period (A) 3 Δ 2 T r r | | | \ . (B) Δ T r r | | | \ . (C) 2 2 3 Δ 2 T r r | | | | \ . (D) None of these Vidyamandir Classes VMC/ 2010 3 BITSAT PRACTICE TEST - 4 13. Between the plates of the capacitor with potential difference V across its plate such that upper plate is ÷ ve, a ball with positive charge ‘q’ and mass ‘m’ is suspended by a thread of length ‘l’. If the electrostatic force acting on a ball is less than the gravitational force, what should be the period of the ball ? (A) 2 l T g t | | = | \ . (B) 2 l qE g m t | | + | \ . (C) 2 l T qE g m t = | | ÷ | \ . (D) 2 lm gE t | | | \ . 14. A pipe GB is fitted with two pipes C and D as shown in the figure. The pipe has area A = 24m 2 at G and velocity of water at G is 10m / s, and at C is 6 m / s. The velocity of water at D is : (A) 21 m /s (B) 3.3 m /s (C) 30 m/s (D) None of these 15. If a conical wire is stretched by two forces F applied parallel to its length and in opposite direction. Normal to end faces. The length of wire is L and its end radius are r 1 and r 2 . Find out the extension produced (Given : Y = Young’s modulus of wire) (A) 2 1 FL r Y t (B) 1 FL rY t (C) 1 2 FL r r Y t (D) 1 2 FLY r r t 16. In a wave motion ( ) y asin kx t e = ÷ , y represent (A) Electric field (B) Magnetic field (C) Displacement, pressure (D) All of these 17. Equation of a plane wave is given by 4 2 4 8 x sin t t + . The phase difference at any given instant of two particles 16 cm apart is : (A) 60° (B) 90° (C) 30° (D) 120° 18. A long tube of length l = 25 cm and diameter equal to 2 cm is taken and at its mouth air is blown as shown in figure. The sound emitted by tube will have all the frequencies of the group (velocity of sound = 330 m/s) (A) 660, 1320, 2640 Hz (B) 660, 1000, 3300 Hz (C) 302, 684, 1320 Hz (D) 330, 990, 1690 Hz Air Vidyamandir Classes VMC/ 2010 4 BITSAT PRACTICE TEST - 4 19. Using the following, data, calculate at what temperature will the wood just sink in benzene Density of wood at 2 3 0 8 8 10 C . kg / m ° = × Density of benzene at 2 3 0 9 10 C kg / m ° = × Cubical expansivity of wood = 4 1 1 5 10 . k ÷ ÷ × Cubical expansivity of benzene = 3 1 1 2 10 . k ÷ ÷ × (A) 27 C ° (B) 21 7 . C ° (C) 31 C ° (D) 31 7 . C ° 20. In case of molecules of an ideal gas, which of the following, average velocities cannot be zero ? (A) v < > (B) 3 v < > (C) 4 v < > (D) 5 v < > 21. If at NTP, velocity of sound in a gas is 1150 m/s, then find out the rms velocity of gas molecules at NTP (Given : R = 8.3 joule/mol/K, C P = 4.9 cal/mol/K) (A) 1600 m/s (B) 1532.19 m/s (C) 160 m/s (D) 16 m/s 22. Surface temperature of the sun as estimated is 6032.25 K. Find the wavelength at which sun radiates maximum energy (Given : Wien’s constant = 0.2898 cm-K) (A) 5000Å m ì = (B) 4804 2Å m . ì = (C) 3809 5Å m . ì = (D) 2891 6Å m . ì = 23. The shortest height of a vertical mirror required to see the entire image of a man, will be : (A) one-third the man’s height (B) half the man’s height (C) two-third the man’s height (D) data insufficient 24. The human eye can be regarded as a single spherical refractive surface of curvature of cornea 7.8 mm. If a parallel beam of light comes to focus at 3.075 cm behind the refractive surface. The refractive index of the eye is : (A) 1.34 (B) 1 (C) 1.5 (D) 1.30 25. If white light is used in Young’s double slit experiment, then the central fringe is : (A) red (B) coloured (C) white (D) blue 26. In relativistic mechanics 0 2 2 1 m m v c = | | ÷ | \ . the equivalent relation in electricity for electric charge is : (A) 0 q q = (B) 0 2 2 1 q q v c = | | ÷ | \ . (C) 0 2 2 1 q q v c = | | ÷ | \ . (D) 0 q v q c = Vidyamandir Classes VMC/ 2010 5 BITSAT PRACTICE TEST - 4 27. Find the force of intraction of two dipoles, if the two dipole moments are parallel to each other and placed at a distance x apart (A) 1 2 4 0 3 4 p p x tc (B) 1 2 4 0 4 p p x tc (C) 1 2 4 0 2 4 p p x tc (D) 1 2 4 0 3 p p x tc 28. The equivalent capacitance between A and B is : (A) 2 1 n C (B) infinite (C) 2 1 2 1 2 C n C | | + + | | \ . (D) zero 29. The drift speed of electron in a conductor is of the order of : (A) 3 10 m/ s ÷ (B) 2 10 m/ s (C) 10 10 m/ s ÷ (D) 8 10 m/ s 30. A circular coil of 100 turns and effective diameter 20 cm carries a current of 0.5 A. It is to be turned in a magnetic field B = 2T from a position in which u equals zero to one in which u equals 180° . The work required in this process is : (A) t joule (B) 2t joule (C) 4t joule (D) 8t joule 31. A magnet of dipole moment 2 Am 2 is deflected through 30° from magnetic meridian. The required deflecting torque is ( ) 4 0 4 10 H B . T ÷ = × (A) 4 0 4 10 . Nm ÷ × (B) 0 4 . Nm (C) 4 0 2 10 . Nm ÷ × (D) None of these 32. A non-conducting ring of radius r has charge per unit length ì . A magnetic field perpendicular to plane of the ring changes at rate dB/dt. Torque experienced by the ring is : (A) 3 dB r dt ìt (B) 3 2 dB r dt ì t (C) ( ) 2 2 2 dB r r dt ì t (D) zero 33. An output voltage of E = 170 sin 377t is produced by an A.C. generator, where t is in sec, then calculate the frequency of alternating voltage (A) 50 Hz (B) 110 Hz (C) 60 Hz (D) 230 Hz 34. How many photons are emitted by a laser source of 3 5 10 W ÷ × operating at 632.2 nm in 2 seconds ( ) 34 6 63 10 h . Js ÷ = × ? (A) 16 3 2 10 . × (B) 10 1 6 10 . × (C) 16 4 10 × (D) None of these 35. In X-ray tube is operating at 15 kV. The lower limit of the wavelength of X-rays produced is : (A) 7 0 82 10 . m ÷ × (B) 8 0 82 10 . m ÷ × (C) 10 0 83 10 . m ÷ × (D) 13 0 82 10 . m ÷ × x P 1 P 2 Vidyamandir Classes VMC/ 2010 6 BITSAT PRACTICE TEST - 4 36. Z component of an orbital angular momentum is h / t , its magnetic quantum number is : (A) 1 (B) 2 (C) 1 ÷ (D) 0 37. When an electron jumps from higher orbit to the second orbit in He + ion, the radiation emitted out will be in ( ) 7 1 1 09 10 R . m ÷ = × (A) ultraviolet region (B) visible region (C) infrared region (D) X-ray region 38. 19 19 O F e v ÷÷÷ + + In this decay, the rest mass energy of O 19 and F 19 are 17692.33 MeV and 17687.51 MeV respectively. The Q factor of the decay is : (A) 4.82 MeV (B) 7 MeV (C) 17.69 MeV (D) None of these 39. Given figure represents : (A) XOR (B) NOR (C) OR (D) NAND 40. One astronomical unit (AU) is equal to : (A) 10 10 m ÷ (B) 11 1 496 10 . m × (C) 15 9 45 10 . m × (D) 11 4 964 10 . m × A B y B A Vidyamandir Classes VMC/ 2010 7 BITSAT PRACTICE TEST - 4 Answers - BITSAT PRACTICE TEST - 4 (2010) 1 2 3 4 5 6 7 8 9 10 D C A A A C C D A B 11 12 13 14 15 16 17 18 19 20 B A C A C D B A B C 21 22 23 24 25 26 27 28 29 30 A B B A C A A B A B 31 32 33 34 35 36 37 38 39 40 A A C A C B B A A B