Laravel getting Database data with Ajax and getting Error 500

I am trying to get some data from my database but I keep getting Error 500.

I can get data from my controller, but when I try to send database info from my controller to the ajax I get an error 500 in Chrome Network

Here is my Controller

public function obtenerEntrada()
{
    //get nombre of Entrada by its id
    $id=$_GET['id'];
    $ent=Entrada::find($id);

    //This works
    return response()->json(['nombre' => $id]);

    //This gives me error 500
    //return response()->json(['nombre' => $ent->nombre]);
}

Here is my Route

Route::get('/obtenerEntrada', 'entradasController@obtenerEntrada');

Here is my Blade with Ajax

$.ajax({
        url:'obtenerEntrada',
        type: 'GET',
        data: {
            id:idprod
        },
        success: function( response ){

            alert(response.nombre);
        },
        error: function () {
            alert('No se encontro el producto');
        }
        });

via Ulises Garibay