what is the ratio of rms speed of oxygen and hydrogen molecule at the same temparature ??????????

The rms speed is given as

v_rms = [3RT/M]^1/2

where M is the molar mass, T is te temperature and R is a constant.

so,

at same temperature, the speed ratios would be

v_rms (oxygen) / v_rms (hydrogen) = [M_hydrogen / M_oxygen]^1/2

or

v_rms (oxygen) / v_rms (hydrogen) =  [0.002 / 0.031]^1/2

thus,

v_rms (oxygen) / v_rms (hydrogen) =  0.25