Magnitude and direction of the force on the dipole, Physics

In class, we learned that the force on a dipole can be written as F = (p.Δ)E

This force can be used to sort particles with no net charge but with a dipole moment in a method called dielectrophoresis (Google it).  This method is often used in biomedical applications to sort particles such as living cells.

Let's work through a problem where we build a dielectrophoresis system.

A particle with  electric dipole moment  p  of magnitude 10-25 Ccm, pointing in the y-direction, is placed midway between two large conducting plates at position xo = 5 cm as shown below.  Each plate makes a small angle Φo = 1o with respect to  the x-axis, with length L=10 cm as indicated, and separated by distance d = 1 mm on the left-hand side. 

The top plate is maintained at potential Vo = 1 V and the bottom plate is maintained at zero potential.  Assume the plates also extend a distance L = 10 cm in the z-direction.

(a) Calculate an expression for the potential between the plates (ignoring the dipole).  Ignore any fringing fields at the edges of the plates. This is the same problem at the end of lab 2.

(b) What is the value of the potential at the centre of the dipole?

(c) Calculate an expression for  the electric field between the plates (due to the plates not the dipole).

(d) What is the magnitude and direction  of the field at the centre of the dipole?

(e) What is the magnitude and direction of the force on the dipole?

(f) The plates in this problem are to be used in a dielectrophoresis experiment to  separate  two different particles of mass 10-8 g and 10-10 g, both with the dipole moment p as defined above. If the particles are initially at rest  at the position shown in the figure below, how long should one run the experiment to separate the two particles by 1 μm?

2176_magnitude and direction of the force on the dipole.png

Posted Date: 3/14/2013 2:51:35 AM | Location : United States

Related Discussions:- Magnitude and direction of the force on the dipole, Assignment Help, Ask Question on Magnitude and direction of the force on the dipole, Get Answer, Expert's Help, Magnitude and direction of the force on the dipole Discussions

Write discussion on Magnitude and direction of the force on the dipole
Your posts are moderated
Related Questions
3 scenarios: You have an object such as a jar, and you submerge it under water to 50m depth. (Every 10m down increases pressure by 1 bar, thus the pressure is 5 bar). Scenario 1:

A ball leaves a girl's hand with an upward velocity of 6 meters per second.  What is the maximum height of the ball above the girl's hand? Ans: A ball leaves a girl's hand w

Resonance: When the frequency of driving force becomes equivalent to the natural frequency of an oscillating system, the driving force gives maximum energy and the oscillating

The operation of a logic gate or circuit can be shown in a table which have all possible inputs and their corresponding output is known as the truth table. To write the truth table

Explain briefly, with the help of circuit diagram, how V - I characteristics of a p-n junction diode are obtained ii (i) forward bias, and (ii) reverse bias. Illustrate th

What is Equipotential Surface Equipotential Surface - surface of constant potential.  No work is required in moving charges with such a surface. Electric fields are perpend

A mass M moves horizontally along a smooth rail. A pendulum is hung from M with a weightless rod and mass  m  at its end. Find the eigen frequencies and describe the normal modes

With mans lust for the unknown in space exploration, what will happen to our planet by removing so much weight in the form of spacecraft that will never return and can the earth re

A 3Kg bar of aluminum has to be heated from 25 degrees Celsius to 75 degrees Celsius. how many calories are needed to achieve this temperature increase?

The signal which has only two values. I.e. either a constant high value of voltage or zero value is known as digital voltage signal