Correct option is : (4) 225 N
At surface: \(\mathrm{mg}=300 \mathrm{~N}\)
\(
\mathrm{m}=\frac{300}{\mathrm{~g}_{\mathrm{s}}}
\)
At Depth \(\frac{\mathrm{R}}{4}: \mathrm{g}_{\mathrm{d}}=\mathrm{g}_{\mathrm{s}}\left[1-\frac{\mathrm{d}}{\mathrm{R}}\right]\)
\(g_{d}=g_{s}\left[1-\frac{R}{4 R}\right]\)
\(\mathrm{g}_{\mathrm{d}}=\frac{3 \mathrm{g}_{\mathrm{s}}}{4}\)
weight at depth
\(\begin{aligned}
& =\mathrm{m} \times \mathrm{g}_{\mathrm{d}} \\
\end{aligned}\)
\(\begin{aligned}
=\mathrm{m} \times \frac{3 \mathrm{g}_{\mathrm{s}}}{4} \\
\end{aligned}\)
\(
\begin{aligned}
& =\frac{3}{4} \times 300 \\
\end{aligned}
\)
\(=225 \mathrm{~N}\)
