Step 1: RMS value of \(f(x)\) in \([a,b]\) is:
\[
\sqrt{\frac{1}{b-a}\int_a^b [f(x)]^2\,dx}
\]
Step 2: Here,
\[
f(x)=x^2,\qquad a=0,\qquad b=1
\]
Step 3:
\[
\text{RMS}=\sqrt{\int_0^1 x^4\,dx}
\]
Step 4:
\[
=\sqrt{\left[\frac{x^5}{5}\right]_0^1}
\]
\[
=\sqrt{\frac{1}{5}}
\]
\[
=\frac{1}{\sqrt5}
\]
\[
\boxed{\frac{1}{\sqrt5}}
\]