40 likes | 116 Views
Help Session. Ch-24. 071. Q10. What is the external work required to bring four 3.0×10 -9 C positive point charges from infinity and place them at the corner of a square of side 0.12 m (Ans: +3.7 μJ)
E N D
Help Session Ch-24
071 • Q10. What is the external work required to bring four 3.0×10-9 C positive point charges from infinity and place them at the corner of a square of side 0.12 m (Ans: +3.7 μJ) • Q11. A point charge q1 = + 2.4 μC is held stationary at the origin. A second point charge q2 = - 4.3 μC moves from x1= 0.15 m, y1= 0 to a point x2 = 0.25 m, y2 = 0.25 m. How much is work done by the electric force on q2 ? (Ans: 0.36 J) • Q12. An electron is accelerated from a speed of 3×106 m/s to 8×106 m/s. Calculate the potential through which electron has to pass to gain this acceleration? (Ans: 157 V) • Q13. The electric potential in a certain region is described by V(x,y, z) = 2xy- 4x2 + 6y. Find the magnitude of the net electric field at x = -1 and y = 1? (Ans: 11 N/C) • Q14. A conducting sphere with a radius of 10 cm, has a surface charge density of 4 ×10−6 C/m2. The electric potential, at r = 5 cm from the center of the sphere is ( assume V= 0 at infinity): (Ans: 4.5×104 V)
T062 • Q8. Calculate the ratio of the speed of a proton to that of an electron, both accelerated through the same potential difference. (Ans: 0.023) • Q10.: Two charged spherical conductors having radii 4.0 cm and 6.0 cm are connected by a long conducting wire. A total charge of 20 μC is placed on this combination of two spheres. Find the charges on each sphere (smaller first). (8 μC and 12 μC) • Q11.: Figure (3) shows three charges located at the corners of a triangle. How much energy would be needed to remove the 4 μC charge to infinity? [Assume V = 0 at infinity.] (8.2J) • Q12: Three concentric spherical shells A, B and C, of radii a, b and c (a<b<c), have charges q, -q and q respectively. The potential of C is: (Vc=kq/c)
T061 • Q#10. A 5-cm radius conducting sphere has a surface charge density of 2 ×10−6 C/m2 on its surface. The electric potential, at r = 2.5 cm from the center of the sphere is: [Assume V = 0 at infinity.] (Ans:1.1 × 104 V ) • Q#11. The diagram in Fig. 1 shows four pairs of, identical, large parallel conducting plates. The value of the electric potential is given for each plate. Rank the pairs according to the magnitude of the electric field between the plates, least to greatest. (Ans: 2,4, 1, 3) • Q#12. An electron starts from rest at a point 10 cm from a positively charged conducting plate, with a surface charge density σ = +1 × 10-9 C/m2. The electron is attracted to the plate until it collides with the plate. With what speed will the electron collide with plate? (Ans: 2.0×106m/s • Q#13. A point charge of 5.0 × 10-9 C is transferred, by an external agent, from infinity to the surface of a ball of radius 5.0 cm. If the ball has the charge density 5.0 × 10-4 C/m2, then the amount of work done, by the external agent, in the process is: [Assume V = 0 at infinity.] (Ans:1.4×10-2 J)