Day 10: Dipole Moments and Electric Flux

At the beginning of the class, we drew the sketch about two lines filled with positive particles and negative particles. The red arrows represent the direction of the electric field. And the electron is moving toward the positive side.

This photo shows the electric dipole in an electric field, which the direction of the electric dipole is from negative to positive. And the direction of forces of two particles are opposite.

We found that dipole moment is p = 2aq and τ = F*r Therefore, the net torque is P*E.

We also found the change in potential energy to be the work. And we got U = PE(cosθ 1- cosθ 2).

The red arrows are the direction of normal vectors of the electric dipole.

The true normal vectors of the electric dipole using vpython.

This shows the electric field lines between a positive and a negative particle and the direction of electric field is always from positive to negative.

This is normal vectors we drew on the lab manual.

Then, we began to talk about flux, and we found the unit of flux to be Nm^2/C

In this photo we find the Flux of 4 different surfaces in the cube. Since the electric field lines is from left to right, the flux of surface 3 and 4 is 0. And the flux of surface 1 and 2 can be calculated by the equation Φ = E*A.

Conclusion

In today's class, we learned about dipole moments and how to find torque of dipole. 

We used vpython to draw the direction of normal vectors of the electric dipole. Also, we learned
about electric flux of different surfaces through a cube