The steam point and the ice point of a mercury thermometer are marked as  800 and  200. What will be the temperature in centigrade mercury scale when this thermometer reads 320

relation between centigrade thermometer and unknown thermometer is C100=X−LFPUFP−LFP C is reading on centigrade thermometer;X  is reading on unknwn thermometer=32 LFP is lower fixed point=20;UFP is upper fixed point=80 substitute given values in above relation ⇒C100=32−2080−20 ⇒C100=1260 ⇒C=1206=200C