Solve the problem 74

73 (a) If an isolated conducting sphere 10 cm in radius has a net charge of 4.0 uC and if V = 0 at infinity, what is the potential on the surface of the sphere? (b) Can this situation actually occur, given that the air around the sphere undergoes electrical 293 breakdown when the field exceeds 3.0 MV/m? 74 Three particles, charge q1 = +10 MC, 92 = -20 uC, and 93 = +30 uC, are posi- tioned at the vertices of an isosceles triangle a a as shown in Fig. 24-62. If a = 10 cm and b = 6.0 cm, how much work must an external agent do to exchange the positions of (a) q1 and q3 and, instead, (b) q, and q2? 42 41 75 An electric field of approximately Figure 24-62 100 V/m is often observed near the surface of Problem 74. Farth If this the field