Noun か Noun か

The structure A か B か, where A and B are either nouns or phrases, is used to "present alternatives", as Tobira says. It generally translates as something like "either A or B" or "whether A or B." If B is followed by a particle, the second か is usually dropped.

東京から九州まで新幹線で行くか飛行機で行くか、まだ決めていないんです。
I haven't decided whether to fly or take the bullet train from Tokyo to Kyushu.

その店がおいしかったかまずかったか覚えていますか？
Do you remember whether that restaurant was good or bad?

最近のケータイは複雑すぎて、便利か便利じゃないか分からない。
The latest cell phone is too complicated. I don't know whether it's convenient or not.

私は毎朝ジュースか水を飲む。
I drink either juice or water every morning.