A) 5 sec
B) 10 sec
C) 15 sec
D) 20 sec
Correct Answer: D
Solution :
\[{{I}_{1}}D_{1}^{2}{{t}_{1}}={{I}_{2}}D_{2}^{2}{{t}_{2}}\] Here D is constant and \[I=\frac{L}{{{r}^{2}}}\] So \[\frac{{{L}_{1}}}{r_{1}^{2}}\times {{t}_{1}}=\frac{{{L}_{2}}}{r_{2}^{2}}\times {{t}_{2}}\]\[\Rightarrow \frac{60}{{{(2)}^{2}}}\times 10=\frac{120}{{{(4)}^{2}}}\times t\Rightarrow 20\ sec\]
You need to login to perform this action.
You will be redirected in
3 sec
