iitjee 2006

Section II: Multiple Choice Questions with one ormore correct answer(s).Q.13 An infinite wire carrying current Ι passes throughpoint O perpendicular to the plane containinga current carrying loop ABCD as shown in thefigure.CB(a) friction force is dissipative(b) on decreasing θ, frictional force decreases(c) friction force does help in rotation andopposes translation(d) friction force is necessarily µmgcosθAns. (b, c)Q.16 The given figure shows lines of force of aparticular field. Out of the following option, thefield line can not represent.IOAD(a) Net force on the loop is zero(b) Net torque on the loop is zero(c) The loop rotates in anticlockwise directionas seen from O(d) The loop rotates in clockwise direction asseen from O Ans. (a, d)(a) An electrostatic field(b) A magneto static field(c) A gravitational field(d) An induced electric fieldAns. (a, c)Q.14 A ball is rolling on the track as shown in thefigure. AB is rough surface and BC is smooth.Ball reaches to the height C. K A, K Band K Care the kinetic energies at A, B and C.Q.17 The adjacent figure shows variation of electricpotential with distance for a spherical symmetriccharge distribution system and given asqφr=4πε0r(r ≥ R0)Ah Ah CCqφr= (r ≤ R0)4πε0R0Which of the following option is/are correct ?φ rB(a) h A> h C; K B> K C(b) h A < h C ; K B > K C(c) h A= h C; K B= K C(d) h A> h C; K A< K CAns. (a, d)Q.15 A solid cylinder is rolling over an inclined planeas shown in the figure.θR 0r(a) For spherical region r ≤ R 0 total electrostaticenergy stored is zero(b) Within r = 2R 0, total charge is q.(c) There will be no charge anywhere except atr = R 0(d) Electric field is discontinuous at r = R 0Ans. (a, b, c, d)CAREER POINT, 112, SHAKTI NAGAR , KOTA (RAJ) PH. 25004923PAPER - IIT-JEE-2006