Simply Clickable Button To URL?

have an app. I just want to add to it a button which when clicked opens a browser to "google.com" website. This is the button code:

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Website" />

I don't know what to put on the activity code.