Lazy L -
For studying flashcards, there is a wonderful website "hamstudy.org". Free. They also make an app for your smartphone/tablet with the flashcards (same content as the website). That app sells for $3 IIRC. The one thing that may be problematic with the flash cards if you are trying to study, say, only one chapter in the ARRL book and you haven't read the other chapters yet - you cannot tell hamstudy.org to ONLY ask you questions from a specific chapter. You CAN tell hamstudy.org to ask you only questions from only a single "Topic", but "Topics" do not match up to "Chapters". When you're reading a book, generally you read it by chapters, you don't jump all over the place trying to follow a topic.
However, this "Questions by Chapter" deficiency has been rectified by a third party website that provides links into hamstudy.org where you CAN tell it to ask you questions only from one chapter. That third party website is:
AFØW / WØUM Amateur Radio Resources
Since it looks like you're studying for the General Exam (I recognize your transistor question above as being on the general test), then from the "gobgk" website above, choose "HamStudy.org General Flashcards". On the resulting webpage, the choices should be fairly obvious. On the right side of the page are "Flashcards by Chapter", on the left side are "Flashcards by Module". A "Module" is basically a subheading in a "Chapter". e.g., you are looking at, say, Chapter 4. Within Chapter 4 there are sections 4.1, 4.2, 4.3, etc. Each of those is a "Module".
These websites above cover all the questions for the current license levels - Technician, General, and Amateur Extra
Note: The flashcards will loop back to the beginning when you finish a chapter, module, topic, etc. This may get confusing on the very first chapter of the first license level - Technician. Because there is only ONE question from that first chapter. So it keeps looping back to itself after you answer it, leading you to think that hamstudy.org is broken. It's not, this is just an anomaly that presents itself if there is only one question available for the requested chapter (I think the only case of that happening is the first chapter of the first license level).
Note: On the flashcards, IAFTER you answer the question, there is a little clickable part on the upper right of the card (looks like a dog-eared corner of a paper page). If you click on that it shows you additional information about the question and answer to the flashcard.