The formula for the effective rate of interest is:
\(\text{Effective Rate} = \left( 1 + \frac{r}{n} \right)^n - 1,\)
where \(r = 0.1\) (nominal rate) and \(n = 2\) (compounding frequency per year).
Substitute into the formula:
\(\text{Effective Rate} = \left( 1 + \frac{0.1}{2} \right)^2 - 1 = \left( 1 + 0.05 \right)^2 - 1.\)
Simplify:
\(\text{Effective Rate} = (1.05)^2 - 1 = 1.1025 - 1 = 0.1025 = 10.25\%.\)
Thus, the effective rate of interest is \(10.25\%\).