Tiêu đề 13 JUNE PW PAPER.pdf ✅

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PHYSICS 1. The electrical potential at a point (x, y, z) is given by V = –x 2y – xz3 + 4 The electric field E at that point is (A) ( ) E 2xy z i x j 3xz k 3 2 2 ˆ ˆ ˆ = + + + (B) ( ) ( ) ˆ ˆ ˆ 2 2 2 E 2xyi x y j 3xz y k = + + + − (C) E z j xyzi 3 k 3 2 ˆ ˆ ˆ = + + (D) ( ) E 2xy z i xy j 3x zk 3 2 3 ˆ ˆ ˆ = − + + 2. Just outside a sharp point on a conductor, we will have a large______than just outside gradually curving places on the conductor. (A) Electric field (B) Potential (C) Both (A) and (B) (D) None of these 3. Two thin wire rings each have a radius R are placed at a distance d apart with their axes coinciding. The charge on the two rings +q and –q. The potential difference between the centers of the rings is (A) zero (B) 2 2 0 q 1 1 4 R R d       −      − (C) 2 0 qR 4 d  (D) 2 2 0 q 1 1 2 R R d       −      + 4. Mark the correct statement (A) A solid conducting sphere holds more charge than a hollow conducting sphere of the same radius. (B) Two equipotential surfaces may intersect (C) When a conductor is earthed, charge always flows from conductor to earth (D) No work is done in taking a positive charge from one point to another point inside a negatively charged metallic sphere. 5. The linear charge density of the semicircular ring on both side is same in magnitude. The electric field intensity at O is along (A) ˆ i (B) ˆ −i (C) ˆ j (D) ˆ − j 6. An electric dipole is placed at the center of a sphere select the correct option. (A) The electric field is zero at every point of the sphere (B) The flux of the electric field through the sphere is zero (C) The electric field is not zero at anywhere on the sphere (D) Both (B) and (C) 7. Figure below shows regular hexagons, with charges at the vertices. In which of the following cases, the electric field at the centre is non-zero? (A) (B) (C) (D) 8. If the flux of the electric field through a closed surface is zero, then (A) The charge outside the surface must be zero (B) The electric field must be zero everywhere on the surface (C) The total charge inside the surface must be zero (D) The electric field must be uniform throughout the closed surface 9. A circular ring carries a charge Q, the variation of electric field with distance x measured from center along axis for x >> R can be given as [R → Radius of ring] (A) 3 1 E x  (B) E  x (C) 2 1 E x  (D) 1 E x  PW-AITS_NT-07
10. The variation of electric field between the two charges q1 and q2 along the line joining the charges is plotted against distance from q1 (taking rightward direction of electric field as positive) as shown in the figure. Then the correct statement is q1 q2 r (A) q1 and q2 are positive and |q1| > |q2| (B) q1 and q2 are positive |q1| < |q2| (C) q1 positive and q2 is negative |q1| < |q2| (D) q1 negative and q2 is positive |q1| > |q2| 11. Find the magnitude of net dipole moment of the following system. (A) qa 21 (B) qa 13 (C) 4qa (D) Zero 12. The unit of electric flux is (A) 2 2 N m C − (B) 2 2 N C m− (C) V-m (D) V-m3 13. The figure shows the path of a positively charged particle 1 though a rectangular region of uniform electric as shown in the figure. The direction of deflection of particle 2, 3 and 4, is (A) Down, down, up (B) Up, up, down (C) down, up, down (D) up, down, down 14. Consider two concentric spherical surface S1 with radius R and S2 with radius 2R both centered at the origin. There is a charge + 2q at the origin and there are no other charges. Compare the flux 1 through S1 with the flux 2 through S2 (A) 1 2  = 2 (B) 1 2  = 4 (C)  =  1 2 (D) 2 1 2   = 15. Consider a non-conducting shell as shown in figure. If we apply Gauss’s law over the non- conducting shell as Gaussian surface. enclosed 0 q E·dA     =     the E is due to (A) q1 and q2 alone (B) q1, q2 and q3 alone (C) q3 and q4 along (D) All charges q1, q2, q3 and q4 16. If n drops, each of capacitance C, coalesce to form a single big drop, then the ratio of the energy stored in the big drop to that in each small drop will be (A) n :1 (B) 1 3 n :1 (C) 5 3 n :1 (D) n 2 : 1 17. Plates of area A are arranged as shown. The distance between each plate is d, the net capacitance is (A) 0A 2d  (B) 0 5 A d  (C) 0 6 A d  (D) 0A d  18. A capacitor of capacitance C is initially charged to a potential difference of V volt. Now it is connected to a battery of 2V with opposite polarity. The heat developed is (A) 3 2 CV 2 (B) 9 2 CV 2 (C) CV2 (D) 9 2 CV 4 19. Two capacitors C1 = C and C2 = 3C are connected as shown in figure. Initially, key K is open and capacitor C1 holds charge Q. after closing the key K, the charge on each capacitor at steady state will be (A) Q Q , 4 4 (B) Q 3Q , 4 4 (C) 3Q 3Q , 4 4 (D) Q ,Q 3
20. What is the force on a dipole of dipole moment P placed as shown (A) 3 0 q P 4 a  downward (B) 3 0 q P 4 a  upward (C) 3 0 q P 2 a  downward (D) 3 0 . 2 q p  a upward 21. An electroscope is given a positive charge. Causing its foil leaves to separate. When an object is brought near the top plate of the electroscope. The foils separate even further. We could conclude (A) that the object is positively charged (B) that the object is electrically netural. (C) that the object is negatively charged (D) only that the object is charged. 22. Two large parallel sheets uniformly with surface charge density  and –  are located as shown in the figure. Which one of the following graphs shows the variation of electric field along a line perpendicular to the sheets: (A) (B) (C) (D) 23. To form a composite 16F, 1000V capacitor from a supply of identical capacitors marked 8F, 250V, we require a minimum number of n capacitors, where n is: (A) 2 (B) 8 (C) 16 (D) 32 24. Three capacitors C1, C2 and C3 are connected to a battery as shown in the figure. The three capacitors have equal capacitance. Which capacitor stores the most energy? (A) C2 or C3 as they store the same amount of energy (B) C2 (C) C1 (D) All three capacitors store the same amount of energy 25. The work done in bringing a 20C charge from point A to point B for distance 0.2m is 2J. The potential difference between the two points will be: (A) 0.2V (B) 8V (C) 0.1 V (D) 0.4 V 26. At a certain distance from a point charge, the field intensity is 500V/m and the potential is–3000V. The distance to the charge and the magnitude of the charge respectively are: (A) 6m and 6C (B) 4m and 2C (C) 6m and 4C (D) 6m and 2C 27. A and B are two concentric spheres. If A is given a charge Q while B is earthed as shown in figure: (A) The charge density of A and B are same (B) The field inside and outside A is zero (C) The field between A and B is not zero (D) The field inside and outside B is zero 28. Let E be the E-field and V the potential at of centre of square having charges on the vertices as shown in figure. If the charges on A and B are interchanged with those on D and C respectively, then. (A) E change V remains same (B) E remains same. V changes (C) Both changed (D) Both remains same.