the answers of your questions are as below
1) What is meant by Silverlight?
Microsoft Silverlight is a programmable web browser plugin that enables features such as animation, vector graphics and audio-video playback that characterise rich Internet applications. Version 2.0, released October 2008, brings additional interactivity features and support for .NET languages and development tools. It is compatible with multiple web browser products used on Microsoft Windows and Mac OS X operating systems. Mobile devices, starting with Windows Mobile 6 and Symbian (Series 60) phones, will also be supported. A third-party free software implementation named Moonlight is under development to bring compatible functionality to GNU/Linux.
2) What is the purpose of using Silverlight?
Silverlight is a plugin from Microsoft that is a lot like Macromedia Flash. If a developer has developed something for their site written with Silverlight instead of Flash, you won't be able to view it without the plugin. There are many features that Silverlight has that Flash does not, however, Flash is still the more popular of the two plugins. For more information on Silverlight, browse the links in the 'Related Links' section.
3) What are the things required to run and implement the Silverlight?
1) What is the abbreviation of XAML?
XAML Extensible Application Markup Language (Microsoft)
XAML Transaction Authority Markup Language (vendor neutral transaction standard)
2) What is the purpose of using XAML?
XAML is an XML-based declarative markup language suitable for representing nested object hierarchies, such as those of CLR objects. This makes it a good choice for building user interfaces (which are inherently nested and hierachical). This is how Windows Presentation Foundation employs XAML. Windows Workflow on the other hand employs XAML to orchestrate workflows.
rest you can search on google about anything you want....