The root mean square (rms) speed of hydrogen molecule at STP is 2km per second. The rms speed of oxygen molecule at 810°C is (molecule weight of hydrogen and oxygen are $2$ and $32$ respectively.)

2 km s^-1

2 km s^-1

0%

1 km s^-1

1 km s^-1

0%

0.5 km s^-1

0.5 km s^-1

0%

4 km s^-1

4 km s^-1

0%