Two simple pendulums A and B having lengths l and, l/4 respectively are released from the position as shown in figure. The time after which the release of the two strings become parallel for the first time is_______. [Take l=90π2 and g=10ms-2]

The angular position of pendulum I and 2 are(taking angles to the right of reference line xx' to be positive)θ1=θcos⁡4πTt                                 where T=2πlgθ2=−θcos⁡2πTt=cos⁡2πTt+πFor the strings to be parallel for the first time, θ1=θ2cos⁡4πTt=cos⁡2πTt+π∴4πTt=2nπ±2πTt+π for n=0,t=T2; for n=1,t=T6,3T2Both the pendulum are parallel to each other for the first timeafter t=T6=π3lg=1s