I want to add the arrows as shown in the picture. I an new to latex. Can someone tell the code? i am using beamer class

It was made in powerpoint.
As JohnReed said, you could use TikZ for this: In the shapes.arrows library, there's a very customisable arrow shape that would be well suited for this.
In the example below, I've defined a TikZ style using \tikzset that sets the options common to the up and down arrows, and two maros \arrowup and \arrowdown that use an inline \tikz command to draw the arrows using the new style, only changing the rotation of the arrow. If you want to change the colour or thickness of the arrow, for example, you only need to edit the style, the macros stay the same.

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{shapes.arrows}
\tikzset{
myarrow/.style={
draw,
fill=orange,
single arrow,
minimum height=3.5ex,
single arrow head extend=1ex
}
}
\newcommand{\arrowup}{%
\tikz [baseline=-0.5ex]{\node [myarrow,rotate=90] {};}
}
\newcommand{\arrowdown}{%
\tikz [baseline=-1ex]{\node [myarrow,rotate=-90] {};}
}
\begin{document}
\begin{frame}
\begin{tabular}{rc}
Thermal Grashof number& \arrowup\\[1ex]
Velocity & \arrowup\arrowdown\\[1ex]
Temperature & \arrowdown\\[1ex]
Solutal boundary layer thickness & \arrowdown\\
\end{tabular}
\end{frame}
\end{document}
\includegraphics. You could get arrows pointing in different directions by rotating the graphic using the optional arguments for\includegraphics. – JohnReed Jun 28 '12 at 04:38