(a) The reading should be taken by keeping the level of mercury along the line of sight.
(b) Before use, the mercury level should be below 35°C.
(c) Wash the thermometer with water or an antiseptic solution before and after use.
(d) Never hold the thermometer by the bulb while reading it.
(e) Handle the thermometer with care, it can break if hit against hard object.
The length of wire PQ in case of A is equal to the diameter of the semicircle formed by the wire CDE, in case B. One pin is attached to each wire with the help of wax as shown in figure above. Which pin will fall first? Explain.