Two point charges + q and – q are located at x O and It L respectively. The location of a point on the x axis at which the net electric field due to these two point charges is zero is (a) ALL (b) AL (c) AL (d) AL Two thin wire rings each having a radius R are placed at a distance axes coinciding. The charges on the two rings are + q and – q. The between the centers of the two rings is (a)-q- 1 2) their I c 1 4-?ere R q (d) zero 3 A parallel plate capacitor is made by stacking n n… Alternatively.

If the capacitance -?paced I IEEE 2005 1 plates connected is ‘C’, then the resultant 4) A charged ball B hangs from a silk three-? h. Makes an angle & with a large conducting sheet P, as shoo in figure. The surface charge density o of the sheet is pr to (a) cot& (b 1 coos e (c) tan & (d I IEEE 2005] 6) B and C having equal radii and carrying equal charges in them force F when kept apart at some distance. A third spherical r having same radius as that of B but uncharged, is brought in contact with B, brought in contact with C and finally removed away from both.

The new force of, , . :-a. Rep 1st on between B and C al OFF(b 13 84 (CLC 88 (ODL 3 81 IEEE 2004 ] A charged particle q is shot towards another charged particle Q, which is fixed, with a speed v. It approaches Q Upton a closest distance r and then returns. If q was given a speed v, the closest distance of approach would be (a) r (b) or (c) ROR 2004 ] ( Answers at the end of all questions Page 2 81 Four charges equal to -Q are placed at the four corners of the square and a charge q Is at its centre. If the system is In equilibrium, the value of q is (a Q 4

If both the spheres are separated, then surface density of the charges on the spheres will be in the ratio of a) 1:4 (b) 4:1 (e) 1:2 (d) 2:1 ( Sixty four equal charged drops are combined to form a big drop. I each drop is 10 volt, then the potential of the big drop wall be (a) VIVO (b) VI (c) VI (d) VI Three large charged sheets are having surface charge density as shown in the figure. The sheets are placed parallel to XV plane. Then electric field at point P will be (a) 4 . A 18 2002) 19) a Eh -20 ask Gaussian surface flux of the electric due to 20 ) Consider the charge configuration as shown in the figure.

When field over the spherical surface, (a ) q (blob (c ) all the charges (d-? here negative, of 2004 1 21 )SiX charges, three and equal such that the e E at O is double the electric field when only one positive e of the same magnitude is placed at R. Which Off folio Inning arrangement of charges Is possible for P, Q, R, T d ;respectively 7 (a) (d } +, +, +, )lit 2004] T-?–As shell has a point charge ‘ q ‘ kept inside its cavity. Which one of the owing diagrams correctly represents the electric lines of forces ? (IT 2003] Page 4 23) Two equal point charges are fixed at x ” -a and x ” + a on the X-axis.

Another point charge Q is placed at the origin. The change in the electrical potential energy of Q, when it is displaced by a small distance x along the X-axis, is approximately proportional to 23 1 al x lb I x Icily x old II I x Two identical 24) c. One of the 25′ 2002 J of an equilateral I IT 2001 J capacitor A has a charge q on it the capacitor Baa long time after the (e Didst [IT 2001 } electric field pointing in positive X-delectation exists in a region. Let A be the be the point on the X-axis at x +1 me and C be the point on the Y-axis at me.

Then the potentials at A, B and C satisfy VI (b) VI (c) PVC (d) PVC [IT 2001} Three charges Q, + q and + q are placed at the vertices of a right-angled isosceles triangle as shown in the figure. The net electrostatic energy of the configuration is zero if Q is equal to 12 LLC-q I 20001 Page 5 29 I A parallel plate capacitor of area A, plate separation d and capacitance C is fitted with three different dielectric constants kill, k and k as shown in the figure. If a single dielectric material is to be used to have the same capacitance C In this capacitor, then its dielectric constant k is given by 1 1 1 1 k k