Problem in passing params


I have a controller called students_controller.rb

From a view file i am calling the index method by the URL like,

students_path(:format => :json)

I have no problem in that. But i want to pass the teacher_id as the
parameter. Like,

students_path(:format => :json, :teacher_id => 5)

The problem here is, the parameter is passing as,

"amp;teacher_id" => "5"

I want to get the correct params. Is there any way to pass correctly?

Thanks in advance.

- Karthik.