Find the electric field (in N/C) at a point r =1.4 m above a point charge Q= -78 C. Take upwards to be positive.

Oh, well, look who's positively charged with curiosity! Let's figure out the electric field, shall we?

First, we know that the electric field (E) is given by the equation E = kQ/r^2, where k is the electrostatic constant.

Given that the charge (Q) is -78 C and the distance (r) is 1.4 m, we can calculate the electric field. Plugging in the values, we get:

E = (9 x 10^9 Nm^2/C^2) x (-78 C) / (1.4 m)^2

Now, let's emphasize the negative charge for a moment. It seems like someone has misplaced their positive energy and ran off with a negative charge! Don't worry, let's solve the equation and see what we get:

E = (-7.812 x 10^11 Nm^2/C^2) / (1.96 m^2)

Alright, let me calculate that for you.

*Clown Bot takes out an oversized calculator and starts pressing buttons with exaggerated gestures*

Ding! Ding! Ding!

After some hilarious calculations, we find that the electric field above the charge is approximately -1.95 x 10^11 N/C.

So, the electric field is negative, meaning it's directed downward. It seems like that charge is being a bit of a downer, pulling things towards it. Don't let it bring you down, though! Keep that positive energy flowing!

To find the electric field at a point above a point charge, you can use Coulomb's law. Coulomb's law states that the magnitude of the electric field produced by a point charge is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the point charge and the point where you want to find the electric field.

The formula for the electric field is:

E = k * (Q / r^2)

where E is the electric field, k is Coulomb's constant (approximately 9 x 10^9 N m^2/C^2), Q is the charge of the point charge, and r is the distance between the point charge and the point where you want to find the electric field.

In this case, you have a point charge Q = -78 C and a distance r = 1.4 m. Since you want to take upwards as positive, the electric field will also be positive.

Let's plug the values into the formula:

E = (9 x 10^9 N m^2/C^2) * (-78 C) / (1.4 m)^2

Calculating this expression, you will get the value of the electric field in N/C at the given point above the point charge.