laravel get data with relationship code example

Example 1: laravel get only relationship

$products = $popularProducts->pluck('product');

Example 2: how to use where relationship laravel

Event::with(["owner", "participants" => function($q) use($someId){
    $q->where('participants.IdUser', '=', 1);
    //$q->where('some other field', $someId);
}])