Q2. Time periods of oscillation of the same simple pendulum measured using four different measuring clocks were recorded as $4.62 \mathrm {~s} , 4.632 \mathrm {~s} , 4.6 \mathrm {~s}$ and 4.64 s . The arithmetic mean of these readings in correct significant figure is :\\
(1) 5 s\\
(2) 4.623 s\\
(3) 4.6 s\\
(4) 4.62 s