6. A dipole is placed in uniform electric field such that potential energy of dipole is maximum (U). The work done in rotating a dipole by 180 is :- (1) U (3) -2U (2) 3U (4) -U 7. Electric charges q, q, -2q are placed at the corners of an equilateral triangle ABC of side . The magnitude of electric dipole moment of the system is :- (1) ql (2) 2ql (3) 3ql (4) 4ql 8. The path of a positively charged particle 1 through a rectangular region of uniform electric field as shown in the figure. What is the direction of electric field and the direction of deflection of particles 2,3 and 4 ? Top 20 10- 4 Down (1) Top; down, top, down (2) Top, down, down, top (3) Down; top, top, down 9. (4) Down; top, down, down The current through a wire depends on time as i = (2 + 3t)A. Calculate the charge crossed through a cross section of the wire in 10 sec. (1) 100C (2) 120C (3) 150C (4) 170C 10. A wire of resistance 42 is stretched to twice its original length. The resistance of stretched wire would be (1) 202 (2) 4 (3) 8 (4) 1602