Answer is : (d) 10−2 rad s-1
As total momentum remains conserved,
l1ω1 = l2ω2
\(\frac{2}{5}\)MR21ω1 = \(\frac{2}{5}\)MR22ω2 \(\left[\because l=\frac{2}{5}MR^2\right]\)
⇒ R12ω1 = R22ω2
⇒ ω2 = \(\left(\frac{R_1}{R_2}\right)^2\) x ω1
= \(\left(\frac{10^8}{10^5}\right)^2\) x 10-4
= 10-2 rad s-1