How to change Fonts while using AMS-package?

Question

Can I use another font and another size with those packages? I don't like the way, the font turned out in my document(beamer). It is too big and the distance between lines should be smaller.

\usepackage[utf8]{inputenc}
\usepackage{eurosym}

\usepackage[ngerman]{babel}
\usepackage{csquotes}

\usepackage{lmodern} 

\renewcommand\textbullet{\ensuremath{\bullet}}

% Darstellung -----------------------------------------------------------------
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}

Answer 1

Below are the updated code to change the font, newtxtext,newtxmath are the packages used for Times font, and newpxtext,newpxmath are the packages for Palatino font, etc. You can change what you like...

\documentclass{book}
\usepackage[utf8]{inputenc}
\usepackage{eurosym}

\usepackage[ngerman]{babel}
\usepackage{csquotes}

\usepackage{lmodern} 

\usepackage{newtxtext,newtxmath}

\renewcommand\textbullet{\ensuremath{\bullet}}

% Darstellung -----------------------------------------------------------------
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}

\begin{document}

This is for test

\end{document}