If $f\left(x\right)=\left|\frac{x}{2}\right|$ is a real function  then $f:R\to B$ is a surjection  then $B$ equals 

The given function is $f\left(x\right)=\left|\frac{x}{2}\right|$

The Domain of the function is $R$, set of all real numbers. 

The range is only posiitve real numbers including zero

Hence, the range of the function is $\boxed{R^{+}\cup \left\{0\right\}}$