I run a competition/contest website which lists competitions. Users view the details of the listing and then link off to the external competition page.
I have noticed a similar website that has a page after the user enters the competition that they go to which says something like “please wait while we validate your answer to the competition. Please take a moment to visit our sponsors” which has some Adsense on. The page then redirects to a thank you page.
Don’t ask anyone to click on your Google ads. Encouraging users to click on your Google ads is strictly prohibited – whether directly or indirectly, on your own site, on third-party sites, or via email. Users should always click on Google ads because they’re interested in the services being advertised, not to raise money for your site or for a cause, or to generate some sort of reward for themselves.
Also
Please don’t place content ads on interstitial pages