Is there a difference in meaning?

Hello,

Is there any difference in meaning between the following when you want to say "where is..."?

１．本はどこですか。
２．本はどこにありますか。

１．メアリさんはどこですか。
２．めありさんはどこにいますか。

The only difference I can think about is maybe the latter examples are used when the speaker is referring more specifically to a thing/person...

Thanks.

Those are basically the same in most cases, but メアリさんはどこですか also can be used, for instance, to ask her hometown depending on the context. I.e., どこ doesn't always refers to the location where the subject is at now.