Question

Two absolute scales A and B have triple points of water defined to be 200 A and 350 B. What is the relation between TAand TB?
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Answer 1

Triple point of water on absolute scaleA, T1 = 200 A

Triple point of water on absolute scale B, T2 = 350 B

Triple point of water on Kelvin scale, TK = 273.15 K

The temperature 273.15 K on Kelvin scale is equivalent to 200 A on absolute scale A.

T1 = TK

200 A = 273.15 K

∴ A = 273.15/200

The temperature 273.15 K on Kelvin scale is equivalent to 350 B on absolute scale B.

T2 = TK

350 B = 273.15

∴ B = 273.15/350

TA is triple point of water on scale A.

TB is triple point of water on scale B.

∴ 273.15/200 × TA = 273.15/350 × TB

Therefore, the ratio TA : TB is given as 4 : 7.

Answer 2

Solution

Triple point of water on absolute scaleA, T1 = 200 A

Triple point of water on absolute scale B, T2 = 350 B

Triple point of water on Kelvin scale, TK = 273.15 K

The temperature 273.15 K on Kelvin scale is equivalent to 200 A on absolute scale A.

T1 = TK

200 A = 273.15 K

∴ A = 273.15/200

The temperature 273.15 K on Kelvin scale is equivalent to 350 B on absolute scale B.

T2 = TK

350 B = 273.15

∴ B = 273.15/350

TA is triple point of water on scale A.

TB is triple point of water on scale B.

∴ 273.15/200 × TA = 273.15/350 × TB

Therefore, the ratio TA : TB is given as 4 : 7.