DoITPoMS

Questions

Quick questions

You should be able to answer these questions without too much difficulty after studying this TLP. If not, then you should go through it again!

1. What symmetry element must be absent for a material to be piezoelectric?

   	a	An axis of rotation
   	b	A mirror plane
   	c	A centre of symmetry
   	d	An improper axis of rotation

2. Applying a mechanical stress to a piezoelectric does not cause which of these?

   	a	The formation of a dipole moment
   	b	The movement of atoms
   	c	Development of polarisation
   	d	The generation of an internal current

3. The application of an electric field to a piezoelectric does not cause which of these?

   	a	A change in shape of the piezoelectric
   	b	The formation of a magnetic field
   	c	The movement of atoms
   	d	The formation of dipole moments to oppose the field

4. What does 'poling' do?

   	a	Align ferroelectric dipoles to give a net polarisation in a piezoelectric
   	b	Produce a non-polarised ferroelectric
   	c	Increase the dipole moment in each unit cell
   	d	Produces a pole

5. Which of these will not depolarise a poled ferroelectric piezoelectric?

   	a	Applying a very large stress to the piezoelectric
   	b	Applying a reversed electric field to the piezoelectric
   	c	Applying a current perpendicular to the polarisation
   	d	Applying a large amount of heat to the piezoelectric