Question
Could someone please help? Double points for 2 questions!
Q1
Q2
The metal sphere of a small Van de Graaff generator illustrated in the following figure has a radius of 23.0 cm. When the electric field at the surface of the sphere reaches 3.0 Times 106 V/m, the air breaks down, and the generator discharges. What is the maximum potential the sphere can have before breakdown occurs? Two charges of q1 = 1.5 mu C and q2 = ?2.1 mu C are d = 0.34 m apart at two vertices of an equilateral triangle as in the figure below. What is the electric potential due to the 1.5- mu C charge at the third vertex, point P? What is the electric potential due to the ?2.1- mu C charge at P? Find the total electric potential at P. What is the work required to move a 3.9- mu C charge from infinity to P?
Explanation / Answer
The electric potential from a charge q is K*q/r if potential is referenced to 0 at r = ?.
(a) ? = K*1.5*10^-6/0.34
(b) ? = -K*2.1*10^-6/0.34
(c) The distance to P is the same for both charges and = d. The potential at P is the sum of the potentials from the two charges
? = K*1.5*10^-6/0.34 - K*2.1*10^-6/0.34
(d)The work is q*? = q*K*(1.5*10^-6/0.34 - 2.1*10^-6/0.34)