Answer
When immersed in water, there are 45 bright rings formed.
Work Step by Step
When immersed in water, the wavelength of the light changes to $\lambda_n={\lambda\over n}$.
\begin{align*}
\therefore m&={nr^2\over \lambda R}-{1\over 2}\\
\implies m&={1.33\times (10\times 10^{-3})^2\over 589\times 10^{-9}\times 5.0}-0.5\\
m&=44.7
\end{align*}
Hence, when immersed in water, there are 45 bright rings formed.
