Get extension file in Laravel 5

My code in view is like this :

@foreach($news as $row)
    <div class="dealprice">
        <p class="size8 red lh2">File Path: {{ $row->file_path}}</p>
    </div>                  
@endforeach

The result of {{ $row->file_path}} : assets/images/Test.pdf

I want the result : pdf

How do I get the file extension?

Thank you

via Chebli Mohamed