What’s wrong with my use of plugin_url()?

function add_my_css_and_my_js_files(){
    wp_enqueue_script('jquery-validate-min', plugins_url('activate/jquery_validate_min.js', __FILE__ ) );
}
add_action('wp_enqueue_scripts', "add_my_css_and_my_js_files"); 
  1. You need to use the plugins_url() function (you are missing the
    s at the end of plugins).
  2. Reference the location of the script file with the relative path. Meaning the path should be activate/jquery_validate_min.js.