Answer :
Answer:
[tex]q=-2.26\times 10^{-5}\ C[/tex]
Explanation:
Given that,
The mass of a particle, m = 1.48 g = 0.00148 kg
The electric field, E = 640 N/C
We need to find the charge of the particle when placed in a downward-directed electric field.
The force of gravity is balanced by the electric force such that,
mg = qE
Where
q is the charge of the particle
[tex]q=\dfrac{mg}{E}\\\\q=\dfrac{0.00148\times 9.8}{640}\\\\q=2.26\times 10^{-5}\ C[/tex]
q must be negative, the force must be upward (opposite direction of the electric field).