Hi trish,
See here for French and Raven's 5 forms of power:
http://changingminds.org/explanations/power/french_and_raven.htmeg. Expert or referent power could be used by a doctor to pressure an individual into accepting treatment rather than explaining what it is and what it involves ie "You wouldn't understand if I explained it"
Coercive power could be used by a care worker to confuse an individual and get them to make choices that worker wants rather than what they want.
and so on.
Hope that helps
Aunty Sue