Thermometer s sensitivity ?

Why does the liquid in the think thermometer move further than the liquid in the thick tune in the same temperature and same atmospheric temperature?

1 Answer
Jan 27, 2018

Thin thermometer means cross sectional area of the capillary tube is smaller than that of a thick thermometer,so on heating,the rise in level of mercury is more in case of a thin thermometer,than a thick thermometer.

Suppose, on heating mercury by x degree, it's new volume becomes V

Now,for a thin thermometer V = A×l (where, A is the cross sectional area and l is length ,that indicates the rise of mercury in the capillary tube)

And,for a thick thermometer, V = A'×l' (where, A' is the cross sectional area and l' is the increase in mercury level)

Now, we can write,

l/(l') =(A')/A

As, A'>A

So, l>l'

So,increase in the level of mercury in a thin thermometer is more than that of a thick thermometer.

And it is the reason why thin thermometer is more sensitive than thick thermometer.