BITSAT – Grand Test - 2
Transcription
BITSAT – Grand Test - 2
www.sakshieducation.com BITSAT – Grand Test - 2 1. If the dimensions of velocity, acceleration and length are yz–1, yz–2 and xy respectively, the dimensions of the coefficient of friction is 1) x0y0z0 3) x1y0z0 4) x–1y–1z0 If a uniform rod with electrical resistivity ‘s’, mass m, specific heat C, length L, co m 2. 2) x–1y0z0 corss sectional are A and coefficient of linear expansion α is connected across a battery of emf E, then increase in length of this rod in a small time internal t is AE 2 tα sm 2) AE 2 tα smCL AE 2 tα smC ed uc at io n. 1) 3) 4) AE 2 tαL sm 3.In the circuit, shown in fig. ‘K’ is open. The charge on capacitor C in steady state is q1. Now key is closed and at steady state, the charge on C is q2. The ratio of charges is K R C ⎞ ⎟⎟ ⎠ 2R 3 2 2) .s a 1) ks hi E ⎛ q1 ⎜⎜ ⎝ q2 2 3 3) 1 w 4.At a given place where acceleration due to gravity is ‘g’ density ‘d’ kg / m 3 4) m / sec 2 is gently released in a column of liquid of density w w sphere will 1) Fall vertically with an acceleration ‘g’ m / sec 2 2) Fall vertically with no acceleration 3) Fall vertically with an acceleration ⎛d−ρ⎞ g⎜ ⎟ ⎝ d ⎠ 4) Fall vertically with an acceleration ⎛ρ⎞ g⎜ ⎟ ⎝d⎠ www.sakshieducation.com 1 2 , a sphere of lead of ' ρ ' kg / m 3 . If d>ρ, the www.sakshieducation.com 5.A drop of water breaks into two droplets of equal size. In this process, which of the following statement is correct 1) The sum of temperature of the two droplets together is equal to the original temperature of the drop co m 2) The sum of masses of the two droplets is equal to the original mass of the drop 3) The sum of the radii of two droplets is equal to the radius of the original drop 4) The sum of the surface areas of the two droplets is equal to the surface area of the ed uc at io n. original drop 6.Two particles execute S.H.M. of same amplitude and frequency along the same straight line. They pass one another when going in opposite directions, and each time their displacement is half of their amplitude. The phase difference between them is 2) 60° 3) 90° 4) 120° Two point charges 2q and 8q are placed at a distance r apart. Where should a third hi 7. 1) 30° charge – q be placed between them so that the electrical potential energy of the ks system is a minimum .s a 1) at a distance of r/3 from 2q 3) at a distance of r/16 from 2q 4) there is no such position An inductance ‘L’ and capacitance ‘C’ and resistance R are connected in series w 8. 2) at a distance of 2r/3 from 2q w w across an AC source of angular frequency ‘ω’. If ω2 > 1 then LC 1) emf leads the current 2) both the emf and the current are in phase 3) current leads the emf 4) emf lags behind the current www.sakshieducation.com www.sakshieducation.com 9. A straight conductor AB of length 1 m is held horizontally at a certain height in the East - West direction (A is towards East) and is allowed to fall freely. The emf induced between its ends at the instant 2s after dropping it is ( B H = 4 × 10 −5 T , g = 10ms −2 ) 3) 0.8 mV and B is at higher potential 2) 0.4 mV and B is at higher potential co m 1) 0.4 mV and A is at higher potential 4) 0.8 mV and A is at higher potential 10. When a resistance of 9.5Ω is connected across a battery, the voltage across the ed uc at io n. resistance is 11.4V. If the resistance connected across the same battery is 11.5Ω, the voltage across the resistance is 11.5V, then 1) The emf of the battery is 12 V 2) The emf of the battery is 13.5 V 3) The internal resistance of the battery is 1 Ω 4) The internal resistance of the battery is 0.5 Ω hi 11.A gas undergoes a change of state during which 100 J of heat is supplied to it and it does 20 J of work. The system is brought back to its original state through a process ks during which 20 J of heat is released by the gas. The work done by the gas in the second .s a process is 3) 80 J 4) 20 J In two separate collisions, the coefficient of restitutions e1 and e2 are in the ratio w w 12 2) 40 J w 1) 60 J 3:1. In the first collision the relative velocity of approach is twice the relative velocity of separation, and then the ratio between relative velocity of approach and the relative velocity of separation in the second collision is 1) 1:6 2) 2:3 3) 3:2 www.sakshieducation.com 4) 6:1 www.sakshieducation.com 13. A body thrown vertically upwards with an initial velocity u reaches maximum height in 6 seconds. The ratio of the distances travelled by the body in the first second and the seventh second is 2) 11 : 1 3) 1 : 2 4)1 : 11 co m 1) 1 : 1 14. Arrange the following vectors in the increasing order for their orientation with the x- ed uc at io n. axis (c) iˆ + ˆj (a) iˆ + 2 ˆj (b) 5iˆ 1) a,b,d,c 2) c,a,b,d 2iˆ + ˆj (d) 3) d,c,b,d 4) b,d,c,a 15.Time period of revolution of a nearest satellite around a planet of radius R is T. Period of revolution around another planet, whose radius is 3R but having same density is 1) T 2) 3T 3) 9T 4) 3 3T hi 16.A large tank filled with water to a height ‘h’ is to be emptied through a small hole at ks the bottom. The ratio of time taken for the level of water to fall from h to 1) 2 .s a to zero is 2) 1 3) 2 2 −1 4) h 2 and from h 2 1 2 −1 w 17. A uniform rod of length 60 cm and mass 6kg is acted upon by two forces as shown w w in the diagram. The force exerted by 45 cm part ofthe rod on 15 cm part of the rod is 1) 10 N 21N 15cm 2) 17 N 45cm 45N 3) 27 N www.sakshieducation.com 4) 24 N www.sakshieducation.com 18. A body slides down a smooth inclined plane of height h and angle of inclination 30º reaching the bottom with a velocity v. Without changing the height, if the angle of inclination is doubled, the velocity with which it reaches the bottom of the plane is 1. v 2. v/2 3. 2v 4. normal to co m 19. A) When two spheres collide momentum transfer takes place along 2v tangent drawn at contact surface B) When a ball hits a wall at an angle to horizontal its momentum along the wall ed uc at io n. remain constant C) When a ball bounces ‘n’ times before coming to rest the total time elapsed is 2h 1 + e g 1− e t= 1) A,B are true 2) A,C are false 3) A,B,C are true 4) A,B,C are false 20.Two wires A and B of same length, same area of cross-section having the same Young's modulus are heated to the same range of temperature. If the coefficient of linear hi expansion of A is 3/2 times of that of wire B. The ratio of the forces produced in two ks wires will be 1) 2/3 2) 9/4 In a compound microscope, the image formed by the objective is 1) Virtual, erect and magnified 2) real, erect and magnified 3) Real, inverted magnified 4) virtual, erect and diminished w w w 21. 4) 3/2 .s a 3) 4/9 22. In photo electric Experiment, the stopping potential for a given metal is ‘V’ volt when radiation of wavelength λ is used. If radiation of wavelength 2λ is used with same metal, then stopping potential in volt is 1) 2V + hc eλ 2) V + hc eλ 3) V + hc 2eλ www.sakshieducation.com 4) V − hc 2eλ www.sakshieducation.com 23. In Fraunhoffer diffraction 1) The diffraction effect in the direction of the propagation of light only is studied 2) The source and the screen are at infinite distances 4) No lenses are required co m 3) The wave fronts are spherical If λ1 and λ2 denote the wavelengths of de-Brgle waves for electrons in the first and 24. 1) 2:1 ed uc at io n. second Bohr orbits in hydrogen atom then λ1:λ2 is equal to 2) 1:2 3) 1:4 4) 4:1 25. A dog weighing 5 kg is standing on a flat boat so that it is 10 meters from the shore. It walks 4 m on the boat toward the shore and then halts. The boat weighs 20 kg and one can assume that there is no friction between it and water. How far is the dog from the shore at the end of this time? 1)12 m 2) 1.8 m 3) 6.8 m 4) 3.2 m hi 26. A body of mass m is thrown upwards at an angle θ with the horizontal with velocity v 2 + g 2t 2 − (2 v sin θ ) gt 2) (v cos θ − v sin θ ) 2 − gt 4) v 2 + g 2t 2 − (2 v cos θ ) gt w 3) (v cos θ ) 2 + (v sin θ ) 2 .s a 1) ks v. While rising up the velocity of the mass after t seconds will be 27. A balloon of mass M is stationary in air. It has a ladder on which a man of mass m is w w standing. If the man starts climbing up the ladder with a velocity v relative to ladder, the velocity of balloon is 1) m v Upwards M 3) mv Upwards (M + m) 2) 4) mv downwards (M + m) Mv Downwards (M + m) www.sakshieducation.com www.sakshieducation.com 28. A uniform chain of mass 'm' and length 'L' is kept on a horizontal table with half of its length hanging from the edge of the table. Work done in pulling the chain on to the table so that only 1 th of its length now hangs from the edge is, 5 mgl 8 mgl 50 2) 29. A sphere of mass m 3) mgl 18 4) 21mgl 200 co m 1) is tied to end of a string of length l and rotated through the other along a horizontal circular path with speed v . The work done in full horizontal end ed uc at io n. circle is ⎛ mv 2 ⎞ 1) 0 2) ⎜ ⎟ .2π l ⎝ l ⎠ 3) mg .2π l ⎛ mv 2 ⎞ 4) ⎜ ⎟ .(l ) ⎝ l ⎠ 30. A thin rod of mass m and length 2l is made to rotate about an axis passing through its centre and perpendicular to it. If it angular velocity changes from 0 to ω in time t, the torque acting on it is ml 2ω 3t hi ml 2ω 12t 2) 3) ml 2ω t 4) 4ml 2ω 3t ks 1) 31. A body of mass m kg. starts falling from a point 2R above the Earth’s surface. Its .s a kinetic energy when it has fallen to a point ‘R’ above the Earth’s surface [R-Radius of Earth, M-Mass of Earth, G-Gravitational Constant] 1 GMm 2 R w w w 1) 3) 2 GMm 3 R 2) 1 GMm 6 R 4) 1 GMm 3 R 32.A nucleus ZXA emits 9α-particles and 5p particle. The ratio of total protons and neutrons in the final nucleus is 1) Z − 13 ( A − Z − 23 ) 2) (Z − 18 ) ( A − 36 ) 3) (Z − 13 ) ( A − 36 ) 4) (Z − 13 ) ( A − Z − 13 ) www.sakshieducation.com www.sakshieducation.com 33. A liquid is kept in a cylindrical vessel which is being rotated about a vertical axis through the centre of the circular base. If the radius of the vessel is r and angular velocity of rotation is ω , then the difference in the heights of the liquid at the centre of the vessel and the edge is 2 grω 3) ω2 4) 2gr 2 The rectangular surface of area 8 cm x 4 cm of a black body at temperature 1270 C ed uc at io n. 34. r 2ω 2 2g 2) co m rω 2g 1) emits energy E per second. If length and breadth are reduced to half of the initial value and the temperature is raised to 3270 C, the rate of emission of energy becomes 3 E 8 1) 35. 2) 81 E 16 3) 9 E 16 4) 81 E 64 Two identical metal spheres carrying charges +2Q and -6Q separated by a certain distance attract each other with a force F. If they are touched and kept at double 32 F 9 2) repulsive force of 9F 32 F 32 4) repulsive force of F 12 ks 1) Attractive force of hi separation, then the force between them becomes .s a 3) Attractive force of 36. A square frame of side L carries a current i and the field at the centre of the frame is The square frame is recast into a circular loop of radius R. When same current i w B1. w w is passed through the circular loop, the magnetic field at it's centre is B1 B2 1) B2. The ratio is 8 π 2 2) 8 2 π 2 3) 16 π 2 www.sakshieducation.com 4) 8 2 π2 www.sakshieducation.com A ray of light incident on an optical fiber where μcladding =1.4 and μcore =1.6 . The 37. length of the fiber is 2.1km. The time taken by the light ray to come out of the fiber , if the light ray is incident at an angle just greater than the critical angle at core – cladding interface 2) 10.8μ s 3) 2.8μ s 4) 1.28μ s co m 1) 12.8μ s 38. Highest frequency waves are: 2) Microwaves 2) infrared rays 3) ultraviolet rays 4) none of these ed uc at io n. 39 . A particle of placed at the highest point of a frictionless hemispherical surface. If the particle is allowed to slide down, the angular displacement θ at which it will leave the surface is ⎛1⎞ ⎛1⎞ 1) cos −1 ⎜ ⎟ ⎝ 3⎠ 40. ⎛2⎞ 2) cos −1 ⎜ ⎟ ⎝2⎠ 3) cos −1 ⎜ ⎟ ⎝3⎠ ⎛3⎞ 4) cos −1 ⎜ ⎟ ⎝4⎠ A vertical circular loop of wire of radius 9.42 cm is placed with its plane in the magnetic meridian and a short magnetic needle is pivoted at the center of the loop hi so that can freely rotate in the horizontal plane. If a current of 6A is passed ks through the loop, then the needle gets a deflection of (BH = 4 x 10 –5 T) 1) 900 2) 450 4) Does not deflect .s a 3) Continuously rotates about the pivot. w KEY 1 2 w w 1 3 3 1 4 3 5 2 6 4 7 4 8 1 9 4 10 2 11 1 12 4 13 2 14 4 15 1 16 4 17 3 18 1 19 3 20 4` 21 3 22 4 23 2 24 2 25 2 26 3 27 2 28 2 29 1 30 2 31 2 32 1 33 2 34 4 35 4 36 2 37 1 38 3 39 3 40 2 www.sakshieducation.com