Answer to Question #308829 in Electricity and Magnetism for Junard

Question

3. A small sphere of charge +6 x 10-⁶C is suspended by a string of negligible mass. A charge of -9 x 10^-6 C is placed directly to the right of the sphere and 0.22m away from it. The string is deflected 5° from the vertical. Find the tension in the string.

Answer 1

$F=\frac{kq_1r_2}{r^2}=10.04~N,$

$T=F\tan 5°=0.88~N.$