Write down the following formula:
F=m*a
Using the above formula, calculate the force (F) experienced by a particle on the test charge. Variable "m" in the above formula represents the mass in kilograms. The variable "a" denotes the acceleration of the charges in meters per second squared. The data obtained will give you the value for force in newtons. If the data for mass is given in grams, make sure to convert it into kilograms.
Find the value of the test charge (q) in the problem given to you. The magnitude of test charge is generally given in the problem.
Write down the following formula:
E= F/q
This is the basic formula for calculating the electric field (E) at the point where charge is located. Data for the test charge and the force are already obtained in the above steps. Place the values of force and test charge in the above formula. The result obtained will give you the value for the electric field in coulombs. If the charge is positive, the direction of the electric field is opposite the direction of acceleration. If the charge is negative, the electric field and its acceleration have the same direction.