how to call post limited by category

hi, i m calling my post by category name : the given code is working well but i need to do that i want to make limit of post, i want to show only on latest post! can any one tell me how should my arrange while loop or by for loop??

<?php

//The Query
$query = new WP_Query( 'category_name=Business-News' );
echo '<ul>';
 //The Loop
while ( $query->have_posts() ) : $query->the_post();
	echo '<li>';
	$queried_post = get_post($cat_id);
	echo $queried_post->post_thumbnail;
	echo $queried_post->post_content;
	echo '</li>
';
endwhile;
echo '</ul>';
	?>

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