Question

Homework Assignment 1 (Electric Charge and Electric Field: Electrostatics, Coulomb's Law, Electric Field) Problem 21.73 10 of 10 〉 Constants Periodic Table ▼ Part A A water droplet of radius 2.5x102 mm remains stationary in the If the downward-directed electric field of the Earth is 160 N/C, how many excess electron charges must the water droplet have? Express your answer using two significant figures. Submit Return to Assignment Provide Feedback

Answer 1

R = 2.5 times 10^-2 mm V = 4/3 pi R^3 4/3 (pi) (2.5 times 10^-2 times 10^-3)^3 = 65.4498 times 10^-15 m^3 rho_w = 1000 kg/m^3 Mass of drop of water m = rho (v) = (65.4498 times 10^-15) (1000) = 65.4498 times 10^-12 kg Fe = qE = mg q = mg/E = (65.4498 times 10^-12) (9.8)/160 q = 4.008803 times 10^-12 c q = Ne N = 4.008803 times 10^-12/1.6 times 10^-19 = 2.5055 times 10^7 electrons.