An ungraduated mercury thermometer attached to a millimeter scale reads 22.8 mm in ice and 242mm in steam at standard pressure. What will the millimeter read when the temperature is. 20oC?

Answer 1

assuming 100 degree steam
slope = (242 -22.8) /(100 -0)
= 2.19 mm/degree

so 22.8 + 2.19(20) = 66.6 mm