Change jQuery version with hook_form_alter
What you would like to achieve is loading another version of jQery in your form page. You need to understand the way hook system works. hook_js_alter() is defined as:


  "Perform necessary alterations to the JavaScript before it is
  presented on the page."


You can use the above hook to change jQuery version. hook_form_alter() is defined as:


  Perform alterations before a form is rendered.


So, first action is hook_js_alter() and second action is hook_form_alter(). You cannot change jQuery version with the second hook, but you can use the following code.

function mymodule_js_alter(&amp;$javascript) {
  if ($_GET['q'] == "node/add/page") {
     // Swap out jQuery to use an updated version of the library.
  $javascript['misc/jquery.js']['data'] = drupal_get_path('module', 'jquery_update') . '/jquery.js';
  }
}


For more information on using newer versions of jQuery you can refer the Drupal.org article which explains how to add Newer versions selectively using various methods.