OBJECTIVE LEVEL - I 1. A conductor of area of cross-section A having charge carriers, each having a charge q is subjected to a potential V. The number density of charge carriers in the conductor is n and the charge carriers along with their random motion are moving with average velocity v. A current I flows in the conductor. If j is the current density, then → (a) j nqV , in the direction of charge flow → (b) j nqv , in the direction opposite to charge flow (c) | j | nqV , in the direction perpendicular to charge flow (d) | j | nqv , in the direction of charge flow. 2. Two electric bulbs A and B are designed for the same voltage. Their power rating are PA and PB respectively, with PA>PB. If they are joined in series across a V-volt supply, (a) A will draw more power than B (b) B will draw more power then A (c) the ratio of powers drawn by them will depend on V (d) A and B will draw the same power. 3. A non-conducting ring of radius R has two positive point charges lying diametrically opposite to each other, each of magnitude Q. The ring rotates with an angular velocity . If I is the equivalent current then, (a) I Q (b) I 2Q (c) I Q (d) I = ZERO. 4. Three copper wires have their lengths in the ratio 5 : 3 : 1 and their masses are in the ratio 1 : 3 : 5. Their electrical resistance will be in the ratio (a) 5 : 3 : 1 (b) 1 : 3 : 5 (c) 125 : 15 : 1 (d) 1 : 15 : 125. 5. Sixteen resistors each of resistance 16 are connected in the cir- cuit as shown. The net resistance between AB is (a) 1 (b) 2 (c) 3 (d) 4 . A B 6. Two nonideal batteries are connected in parallel. Consider the following statemnents: (A) The equivalent emf is smaller than either of the two emfs (B) The equivalent internal resistance is smaller than either of the two internal resistances (a) Both A and B are correct (b) A is correct but B is worng (c) B is correct but A is worng (d) Both A and B are worng. 7. The equivalent resistance between points A and B in the circuit A B shown is 2R R R (a) R (b) 2 R R (c) 4 (d) 8 . 8. In the circuit shown E, F, G and H are cells of e.m.f. 2V, 1V, 3V and 1V respectively and their internal resistance are 2 , 1 . 3 D B and 1 respectively. (a) V V 2 V (b) V V 2 V D B 13 D B 13 (c) V 13 V G 21 = Potential difference across G (d) V 19 V Potential difference across H. H 13 9. The e.m.f. and the internal resistance of a source which is equivalent to two batteries which are connected in parallel having e.m.f.’s E and r. E1 and E2 and internal resistances r1 and r2 respectively are E E1r1 E2 r2 ; r r r E E1r2 E2 r1 ; r r r (a) (c) (r1 r2 ) E E1r2 E2 r1 ; r 1 2 r1r2 (b) (d) (r1 r2 ) E E1r1 E2 r2 ; r 1 2 r1r2 . (r1 r2 ) r1 r2 (r1 r2 ) r1 r2 10. In the circuit shows in figure, the steady state voltage drop across R3 the capacitor is VC . V C V VR1 V VR 2 R (