A sum of ₹10,000 amounts to ₹12,321 in 2 years at a certain rate of interest per annum, compounded annually. The rate of interest per annum is:

Given:
Principal = ₹10,000
Amount after 2 years = ₹12,321

Compound Interest formula:
$A = P\left(1 + \frac{r}{100}\right)^2$

So,
$12321 = 10000\left(1 + \frac{r}{100}\right)^2$

$\left(1 + \frac{r}{100}\right)^2 = \frac{12321}{10000} = 1.2321$

Taking square root:
$1 + \frac{r}{100} = 1.11$

$\frac{r}{100} = 0.11$

$r = 11%$

Correct Answer: 11%