The acceleration due to gravity on the surface of moon is 1.7 m s ^...

The acceleration due to gravity on the surface of moon is 1.7 m${{s}^{-2}}$ . What is the time period of a simple pendulum on the surface of moon if its time period on the surface of earth is 3.5 s ? (g on the surface of earth is 9.8 m${{s}^{-2}}$)