Question

A conducting sphere with a charge +Q and mass 7.4 g hangs from the horizontal ceiling by a light 21.8-cm insulating thread. When a horizontal electric field of magnitude 1388.5 N/C is turned on, the charge hangs away from the vertical at an angle 82.6º as shown in the figure. The magnitude of the charge Q = Blank 1. Calculate the answer by read surrounding text.
μ C. acceleration due to gravity g =9,80 m/s2 Sate your answer correct to 2 decimal places.

Answer 1

$tanθ = \frac{mg}{qE}$

$θ = 90 – 82.6 = 7.4º$

$tan(7.4) = \frac{7.6 \times 10^{-3} \times 9.81}{q \times 1388.5}$

$q = 4.13 \times 10^{-4} \;C$