Question

An object having a net charge of 24µC is placed in a uniform electric field of 610 N/C directed vertically. What is the mass of this object if it “floats” in the field?

Answer 1

The mass of the object is `1.5×10^-3 kg = 1 .5g.`

Explanation:

The forces acting on the mass are shown in image that I uploaded. The force of gravity points downward and has magnitude mg (m is the mass of the object) and the electrical force acting on the mass has magnitude `F = |q|E`, where `q` is the charge of the object and `E` is the magnitude of the electric field. The object “floats”, so the net force is zero. This gives us: `|q|E = mg` Solve for mass,

`m = (|q|E) /g = (24×10^-6 C)(610 (kg*m/s^2)/C)/ (9.80 m/s^2) =1 .5×10−3 kg`

The mass of the object is `1.5×10^-3 kg = 1 .5g.`