If an inflated tyer bursts, the air escaping out is cooled, why ?

In winter why do bird sits with wings spread out ?

A 'body' which allows the short wavelength incoming solar radiation to enter in but does not allow long wave outgong infrared radiation to escape out is called :

Why is NO_(2) paramagnetic in gaseous state but the solid obtained on cooling is diamagnetic?

Why are substances like platinum and palladium often used for carrying out electrolysis of aqueous solutions?

Thermal conductivity of air is less than of felt but is a better heat insulator in comparison to air why?

In a polymerase chain reaction after the denaturation step why the mixture needs to cool down to a lower temperature ? a) To permit specific annealing of the primers b) To give a halt to the reaction mixture c) To increase the activity of enzyme Taq polymerase d) To obtain the multiple copies of the DNA

Why is NH_(2) group of aniline acetylated before carrying out nitration ?