The compound interest on sum of Rs.  8000 for 1 year at $10\%$ p.a. compounded quarterly

$\text{P}=8000;\text{\hspace{0.17em}\hspace{0.17em}T}=1\text{yrs\hspace{0.17em}\hspace{0.17em}}n=\frac{12}{3}=4\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}R}=10\%\text{p.a}$

$\text{A}=\text{P}{(1+\frac{\text{R}}{400})}^{4n}=8000\times {(1+\frac{10}{400})}^4$

$=8000\times {\left(\frac{41}{40}\right)}^4=8000\times \frac{41}{40}\times \frac{41}{40}\times \frac{41}{40}\times \frac{41}{40}=8830.50$

$\text{C. I}=\text{A}-\text{P}=\text{8830.50}-\text{8000}=\text{830.50}$