If $\int\limits^{a}_{0}3x^2dx=27,$ then value of a is :

2 3 1 $\sqrt{2}$

3

The correct answer is Option (2) → 3 $\int\limits^{a}_{0}3x^2dx=27$ $⇒\left[x^3\right]^{a}_{0}=27$ $⇒a^3=27$ $a=3$