Tiêu đề 18. TEST - ELECTROSTATICS.pdf ✅

PHYSICS DPP DAILY PRACTICE PAPER ELECTROSTATICS DPP No. 18 1. In the following four situations charged particles are at equal distance from the origin. Arrange them the magnitude of the net electric field at origin greatest first (i) (ii) (iii) (iv) (a) (i) > (ii) > (iii) > (iv) (b)(ii) > (i) > (iii) > (iv) (c) (i) > (iii) > (ii) > (iv) (d)(iv) > (iii) > (ii) > (i) 2. A linear charge having linear charge density , penetrates a cube diagonally and then it penetrate a sphere diametrically as shown. What will be the ratio of flux coming cut of cube and sphere (a) 2 1 (b) 3 2 (c) 2 3 (d) 1 1 3. Two charges each equal to ( 3) 1  − q  are placed at the corners of an equilateral triangle of side a. The electric field at the third corner is E3 where ( / 4 ) 2 E0 = q  0a (a) E3 = E0 (b) E3  E0 (c) E3  E0 (d) E3  E0 4. An electron falls through a small distance in a uniform electric field of magnitude 4 1 2 10 −  NC . The direction of the field is reversed keeping the magnitude unchanged and a proton falls through the same distance. The time of fall will be (a) Same in both cases (b) More in the case of an electron (c) More in the case of proton (d) Independent of charge 4q O – 2q X Y 2q –3q X Y O 5q 2q O – q X Y – 3q + + + + a + + + + + + a + + + + + + + 3q O –q X Y

9. Two point charge – q and +q/2 are situated at the origin and at the point (a, 0, 0) respectively. The point along the X-axis where the electric field vanishes is (a) 2 a x = (b) x = 2a (c) 2 1 2 − = a x (d) 2 1 2 + = a x 10. Two identical balls having like charges and placed at a certain distance apart repel each other with a certain force. They are brought in contact and then moved apart to a distance equal to half their initial separation. The force of repulsion between them increases 4.5 times in comparison with the initial value. The ratio of the initial charges of the balls is (a)2 (b) 3 (c) 4 (d) 6 11. The electric field in a region surrounding the origin is uniform and along the x-axis. A small circle is drawn with the centre at the origin cutting the axes at points A, B, C, D having co-ordinates (a, 0), (0, a), (– a, 0), (0, – a); respectively as shown in figure then potential in minimum at the point (a)A (b)B (c) C (d)D 12. In moving from A to B along an electric field line, the electric field does J 19 6.4 10−  of work on an electron. If 1 2  , are equipotential surfaces, then the potential difference ( ) VC − VA is (a)– 4V (b)4V (c) Zero (d)64 V 13. In the following figure two parallel metallic plates are maintained at different potential. If an electron is released midway between the plates, it will move (a) Right ward at constant speed (b) Left ward at constant speed (c) Accelerated right ward (d) Accelerated left ward A E C 1 2 B A D C B E → – 200 V – 400 V