Question Block Countdown
The Running Session screen offers the option of setting a countdown timer for question blocks (separately), which will cause the question block to close automatically once the timer reaches zero. While the question block with an associated timer is active, the countdown will also be shown to participants in the audience view, which can serve as an incentive to participate.
To set a countdown for a question block (except any currently active one), open the block settings menu by clicking on the settings icon on the top of the block. Select "Set time limit" and input the number of seconds you would like the block to be active. Once you have saved the setting, the countdown will automatically start on activation of the question block.