(2012? Suqian) Degreased human hair has the characteristic of elongating when the air is humid and shortening when it is dry. A metal pointer of mass m is fixed at point A on the wooden frame (

According to the information, the device is a lever, A is the fulcrum, and the tension of the degreased human hair and the spring are power and resistance respectively; the degreased human hair has the characteristics of elongating when the air is humid and shortening when it is dry. ． When extended, the spring shortens and the pointer deflects to the right. At this time, the air is humid, that is, it is rainy. The disadvantage of this hygrometer is that it is affected by temperature and air pressure.

So the answer is: 1; right; the error is large (affected by air pressure and temperature).