How to open an application from another application in android?

How can I launch an application from my app. For eg:if there is link in my app and when I click on that link it should open anothe开发者_运维技巧r app.

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Use this.

private void playVideo(){
    startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("vnd.youtube:" + videoId)));
    lastMonoSrc=5;
}