Proper use of <br> tag

If you want to add a blank line between paragraphs you can use <br> tag. Just place it in your html code right after the sentence you want to be separated from other sentence. There is a diffference of <br> tag in Html and Xhtml. In Html you must write <br>, while in Xhtml you must write <br/> to use breaking correctly. As you can see <br/> or <br> tag doesn't have ending tag. This is wrong: <br> <br/> Blogger uses Xhtml so unless you create your website in plain Html you should use <br/> tag.
Example:
Html code: This is a sample text in first line. <br/> This is a sample text in second line
Output:
This is a sample text in first line.
This is a sample text in second line