At room temperature, the average speed of Helium is higher than that of Oxygen by a factor of -

1. $2\sqrt{2}$

2. $6/\sqrt{2}$

3. 8

4. 6

At 27$°$ C, the ratio of root mean square speeds of ozone to oxygen is-

1.$\sqrt{(3/5)}$

2. $\sqrt{(4/3)}$

3. $\sqrt{(2/3)}$

4. 0.25

The temperature at which the r.m.s velocity of carbon dioxide becomes the same as that of nitrogen at 21⁰C is-

1. 462 ^oC

2. 273 K

3. 189 ^oC

4. 546 K