Given
Charge is
[tex]q_1=7.22\text{ nC}[/tex]The second charge is
[tex]q_2=-2.6\text{ nC}[/tex]The distance between the charges,
[tex]r=4.46\text{ cm=4.46}\times10^{-2}m[/tex]To find
The electric field strength
Explanation
The electric field strength is given by
[tex]F=k\frac{q_1q_2}{r^2}[/tex]Putting the values,
[tex]\begin{gathered} F=9\times10^9\frac{7.22\times10^{-9}\times2.6\times10^{-9}}{(4.46\times10^{-2})^2} \\ \Rightarrow F=8.49\times10^{-5}N \end{gathered}[/tex]Conclusion
The electric field strength is
[tex]8.49\times10^{-5}N[/tex]