Question

the resistance of the platinum wire of a platinum resistance thermometer at the ice point is 5 ohm and at steam point is 5.23 ohm .When the thermometer is inserted in a hot bath , the resistance of the platinum wire is 5.795 ohmcalculate the temprature of the bath

Answer 1

Temperature of the hot bath is

=(5.795-5)/(5.23-5)*100

=345.65

Answer 2

Resistance of platinum wire at ice point (0°C) = 5 ohm

Resistance of platinum wire at steam point (100°C) = 5.23 ohm

When the thermometer is inserted in a hot bath,

The resistance of the platinum wire is = 5. 795 ohm

Now, if we suppose

R0 = 5 ohm

R100 = 5. 23 ohm

Rt = 5. 795 ohm

As a = R100 - R0 / R0 x 100 = Rt - R0 / R0 x t

Therefore, Rt- R0 / R100 - R0 x 100

= 5.795 - 5 / 5.23 - 5 x 100

= 345.65°C

So, the actual temperature of the hot bath is 345.65°C as measured by the platinum resistance thermometer.