score:4
I've been in Frankfurt on a connection, and yes, there is an electric store there, it called Pax Electronics.
Yes, it's quite expensive, but they do have such adapters. I've been in PhotAir one, near the Z-gates. You canfind a map here.
Also, such adapters can be found in JFK or other big airports in USA, they have a lot of variants, from $4 (simple) to $20 (multi-format) ones, for example:
Upvote:-1
Most likely you can. You can search for electronic shops in the airport here https://www.frankfurt-airport.com/en/shop---dine/exclusive-offers.overview.map.html#map/category=einkaufen/subCategory=technik-and-entertainment/page=1 (check all levels)
There are plenty of shops past security (airside). Keep in mind that FRA is big. It has two Terminals each with multiple gate areas: Terminal 1 has A, B, C & Z, Terminal 2 has D & E). I'm not sure whether there is an airside connection between the terminals (there is a mono rail train) and area Z is more isolated since it has all the US flights. SO you want to search for a store in your departure gate area.
However, it will be VERY expensive. I would budget for at least 30 Euros. I would recommend to order something online if you can. For example I use a lot of these electronics and chargers https://www.amazon.com/Ckitze-Flat-Europe-Asia-Adapter/dp/B002TZBW74 . I order a dozen and through a handful in my travel bag. The tend to get lost easily !