Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; plgContentJComments has a deprecated constructor in /var/www/astarmathsandphysics/plugins/content/jcomments/jcomments.php on line 25 Call Stack: 0.0000 362552 1. {main}() /var/www/astarmathsandphysics/index.php:0 0.1605 1211976 2. Joomla\CMS\Application\SiteApplication->execute() /var/www/astarmathsandphysics/index.php:49 0.1605 1211976 3. Joomla\CMS\Application\SiteApplication->doExecute() /var/www/astarmathsandphysics/libraries/src/Application/CMSApplication.php:267 0.2280 4110400 4. Joomla\CMS\Application\SiteApplication->dispatch() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:233 0.2293 4137808 5. Joomla\CMS\Component\ComponentHelper::renderComponent() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:194 0.2300 4155520 6. Joomla\CMS\Component\ComponentHelper::executeComponent() /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:356 0.2302 4186552 7. require_once('/var/www/astarmathsandphysics/components/com_content/content.php') /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:381 0.2313 4209272 8. ContentController->execute() /var/www/astarmathsandphysics/components/com_content/content.php:42 0.2313 4209272 9. ContentController->display() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:710 0.3025 4910280 10. ContentController->display() /var/www/astarmathsandphysics/components/com_content/controller.php:113 0.3061 5102432 11. Joomla\CMS\Cache\Controller\ViewController->get() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:663 0.3066 5123360 12. ContentViewArticle->display() /var/www/astarmathsandphysics/libraries/src/Cache/Controller/ViewController.php:102 0.3195 5387680 13. Joomla\CMS\Plugin\PluginHelper::importPlugin() /var/www/astarmathsandphysics/components/com_content/views/article/view.html.php:189 0.3195 5387936 14. Joomla\CMS\Plugin\PluginHelper::import() /var/www/astarmathsandphysics/libraries/src/Plugin/PluginHelper.php:182

Paramagnetism

In an atom, most of the various orbital and spin magnetic moments of the electrons add up to zero. For some metals the atom has a net magnetic moment of the order ofWhen the metal is placed in a magnetic fieldthe field exerts a torqueon each magnetic moment given bywhich tend to align the magnetic moments with the field so as to minimise the potential energy. The net effect is to add to the external magnetic field.

The additional fieldproduced by microscopic electric current loops is proportional to the total magnetic momentper unit volume in the material. This quantity is called the magnetization of the material and is denoted by

The additional magnetic field due to magnetization of the material turns out to be equal towhereWhen such a material completely surrounds a current carrying conductor the total magnetic fieldin the material iswhereis the field cause by the current in the conductor.

A material displaying the behaviour described is called paramagnetic .The magnetic field at any point in the material is greater by a factorcalled the relative permeability of the material. The relative permeability of a vacuum is 1.

The amount by which the relative permeability differs from 1 is called the magnetic susceptibility, denoted bySome values ofm for different material are contained in the following table.

Material

Iron Ammonium Alum

66

Uranium

40

Platinum

26

Aluminium

2.2

Sodium

0.72

Oxygen Gas

0.19

Some material reduce the electric field in the material to levels below any externally applied filed. Such materials are called diamagnetic.