3.PRACTICE TEST-2 (Paper-1)

PART - I (PHYSICS) SECTION - I Straight Objective Type This section contains 7 multiple choice questions. Each question has choices (A), (B), (C) and (D), out of which ONLY ONE is correct. 1. A particle is thrown upwards from ground . It experiences a constant resistance force which can produce retardation 2 m/s2 . The ratio of time of ascent to the time of descent is : [ g = 10 m/s2 ] (A) 1 : 1 (B) 2 (C) 3 (D) 2. System is shown in the figure. Assume that cylinder remains in contact with the two wedges. The velocity of cylinder is - (C) 3 u m/s (D) 7 u m/s 3. A block of mass m1 lies on top of fixed wedge as shown in figure-1 and another block of mass m2 lies on top of another wedge which is free to move as shown in figure-2. At time t = 0, both the blocks are released from rest from a vertical height h above the respective horizontal surface on which the wedge is placed as shown. There is no frcition between block and wedge in both the figures. Let T1 and T2 be the time taken by block in figure-1 and block in figure-2 respectively to just reach the horizontal surface, then : (A) T1 > T2 (B) T1 < T2 (C) T1 = T2 (D) Data insufficient 9. In the figure shown ‘R’ is a fixed conducting ring of negligible resistance and radius ‘a’. PQ is a uniform rod of resistance r. It is hinged at the centre of the ring and rotated about this point in clockwise direction with a uniform angular velocity . These is a uniform magnetic field of strength ‘B’ pointing inwards. ‘r’ is a stationary resistance (A) Current through ‘r’ is zero. 2Ba2 (B) Current through ‘r’ is 5r . (C) Direction of current in external ‘r’ is from centre to circumference. (D) Direction of current in external ‘r’ is from circumference to centre. k 10. A 20 gm particle is subjected to two simple harmonic motions x1 = 2 sin 10 t,  x2 = 4 sin (10 t + 3 ). where x1 & x2 are in metre & t is in sec. (A) The displacement of the particle at t = 0 will be 2 m. (B) Maximum speed of the particle will be 20 m/s. (C) Magnitude of maximum acceleration of the particle will be 200 (D) Energy of the resultant motion will be 28 J. m/s2. 11. The figure shows, a graph of the current in a discharging circuit of a capacitor through a resistor of resistance 10 . (A) The initial potential difference across the capacitor is 100 volt. 1 (B) The capacitance of the capacitor is 10 𝑙n 2 F. (C) The total heat produced in the circuit will be 500 𝑙n2 joules. 1 (D) The thermal power in the resistor will decrease with a time constant 2𝑙n2 second. SECTION - III Comprehension Type This section contains 2 paragraphs. Based upon one of the paragraphs 3 multiple choice questions and based on the other paragraph 2 multiple choice questions have to be answered. Each of these questions has four choices (A), (B), (C) and (D) out of which ONLY ONE is correct. SECTION - IV (Integer Answer Type) This section contains 7 questions. Answer each of the questions in a single-digit integer, ranging from 0 to 9. 17. A gas consisting of rigid di–atomic molecules (degree of freedom = 5) at pressure P = 105 N/m2 and temperature 273 K was compressed adiabatically 5 times. The mean kinetic energy of rotating molecules in final state is n × 10–21 J. Find value of ‘n’. (K = 1.38 × 10–23, (5)2/5 = 1.90). 18. Amount of total charge will flow through point B when the switch 's' is closed will be. (Ans. in µC). 19. A soap bubble of radius 3 cm is charged with surface charge density  such that   = 0.4 S units. The 20. A solid spherical planet has a very narrow tunnel along the diameter. Mass of the planet is 5 × 1024 kg, radius 20 of the planet is 4 × 105 m and value of G is 3 × 10–11 N.m2/kg2. If a particle is at its centre, its escape speed is (x) × 104 m/sec. Find the value of x. 21. A point object is placed at a distance 20 cm from the focus of a concave mirror of radius of curvature 20 cm. Find the distance (in cm) of the image from the focus. 22. A ball is dropped from a height of 16m. After collision with the ground it rises to height 4m. Then the coefficient of restitution(e) is x . Find x. 4 23. A particle of mass 1kg and charge –2C is projected with initial velocity 200 m/s towards a positive charged particle of charge 2C which is fixed. The distance of 1kg particle from heavy particle when speed of 1 Kg x particle is equal to twice of initial value is 107 m. Find the value of ‘x’.