A conducting wire PQ carries a current 10 A as shown in the figure. It is placed in a uniform magnetic field 5 T which is acting normally outside from the paper. Then the net force experienced by it is
 

Magnetic Force is given by $\Rightarrow \overrightarrow{l}=6\hat{i}+8\hat{j}$

$\overrightarrow{F}=i\overrightarrow{l}\times \overrightarrow{B}$

Effective length of the condutor would be 8cm along Y axis and 6 cm along the x axis. 

$\Rightarrow \overrightarrow{l}=6\hat{i}+8\hat{j}$

$i=10 A$

and $\overrightarrow{B}=5 \hat{K}$

On calculating from the above formula 

$\left|\overrightarrow{F}\right|=5 N$