Recurring questions during 30 minute video

Hello,

I want to have users watch a 30 minute video. To ensure they're paying attention, I'd like them to rate the quality of the video every 2 minutes. There'd be 15 ratings total. If possible, I'd love to get the ratings as a dependent variable, but if that's not possible it's just important I know my users maintain vigilance by answering these questions.

TLDR- I need users to watch a video and answer questions as they appear. How do I get them to appear at the correct times?