What is the magnitude of the electric field 0.3 m from a 10-4 C point charge?

To find the magnitude of the electric field, we can use Coulomb's law, which states that the electric field created by a point charge is directly proportional to the charge and inversely proportional to the square of the distance.

Coulomb's law equation is given by:

E = k * (q / r^2)

Where:
E is the magnitude of the electric field
k is Coulomb's constant (approximated to 9 x 10^9 N⋅m^2/C^2)
q is the charge of the point charge in Coulombs
r is the distance from the point charge

In this case, the charge (q) is 10^-4 C, and the distance (r) is 0.3 m. Let's substitute these values into the equation to calculate the magnitude of the electric field:

E = (9 x 10^9 N⋅m^2/C^2) * (10^-4 C) / (0.3 m)^2

First, let's square the distance:

E = (9 x 10^9 N⋅m^2/C^2) * (10^-4 C) / (0.09 m^2)

Now, calculate the fraction:

E = (9 x 10^9 N⋅m^2/C^2) * (10^-4 C) / 0.09

Next, multiply the numerator:

E = (9 x 10^5 N⋅m^2/C) / 0.09

Now, divide the numerator by the denominator:

E = 1 x 10^7 N/C

Therefore, the magnitude of the electric field 0.3 m from a 10^-4 C point charge is 1 x 10^7 N/C.