A ball with a mass of m = 0.1 g and a charge q = 9.8 nC is suspended on a thread in a uniform

A ball with a mass of m = 0.1 g and a charge q = 9.8 nC is suspended on a thread in a uniform electrostatic field, the intensity of which is directed horizontally, and its modulus is E = 10 ^ 5 V / m. Find the angle of deviation of the thread from the vertical.

As we know from the condition, three forces act on the ball. It can be written as follows:
Ft + Fn + Fe = 0;
It also follows from the condition that the following forms are needed for the solution:
1. Fe = m * g * tg a;
2. Fe = E * q;
Let’s transform:
tg a = m * g / E * q;
Let’s substitute:
tg a = 0.1 * 10-3 * 9.8 / 9.8 * 10-9 * 105;
Let’s count:
tg a = 10-4 / 10-4;
tg a = 1;
tg a = 45 °.
Answer: a = 45 °.