worthy or worthwhile

[eeshu]

In today's test, I hit upon a word derivation item, asking the students to complete a sentence with the appropriate form of the word provided in the brackets. Here is the test item:

She is willing to donate more money to a ______ cause. (worth)

The answer is "worthy", but I think "worthwhile" is also correct. Am I right? If both are acceptable in such a context, is there any difference between them? Thanks for enlightenment.

[Rolex_Cellini]

worthwile (something that is worth its while = worths its time, trouble, or expense)
worthy:
worthy cause (=an activity or organization that helps people): The money will go to a worthy cause.
http://www.macmillandictionary.com/d...orthy#worthy_4

Both are fine.

[SoothingDave]

"Worthy cause" is the common expression.

[eeshu]

"Worthy cause" is the common expression.

But all the following sentences from the Longman Dictionary of Contemporary English (5th edition) suggest that "worthwhile cause" is also a common collocation.

COLLOCATIONS FROM CORPUS
■ NOUN
cause
▪ Triodos's range of accounts includes six Partnership Accounts that allow savers to channel money into worthwhile causes.
▪ If you wish to contribute to this worthwhile cause, please see below for details.
▪ It's a simple idea which should channel hundreds of millions of pounds into worthwhile causes.
▪ Council leader Christopher Kingsley said the restoration project will create local jobs and was a worthwhile cause.

and the Oxford Collocations Dictionary also says

"Worthwhile is used with these nouns: cause, effort, end, endeavour, exercise, idea, investment, job, project, read, reading, trip, undertaking."

Is there such a difference in usage between American English speakers and British English speakers?

[emsr2d2]

I can see the similarity but I would use them slightly differently.

Volunteering for the charity was a worthwhile use of my time. (My time was well spent)

I volunteer for that charity. It's a worthy cause. (The cause deserves my time and effort)

It's a worthy cause. (It deserves recognition, time and effort)
It's a worthwhile cause. (What it does is useful)

[eeshu]

Many thanks.