Infrared wave cooking vs microwave radiation

[sgstudent]

I have learned that penetration ability increases with frequency. But why can microwave cook faster than infrared wave? Infrared gas a greater frequency so it should penetrate more and thus cook faster. So I'm not so clear about this.

Thanks for the help

 

[nasu]

I have learned that penetration ability increases with frequency.

This is not so in general. It may be true for some domain of frequency and for some materials but definitely not true in general.
For example, radio waves penetrate easily wooden walls whereas light usually don't.