Question

Two absolute scale $A$ and $B$ have triple points of water defined to be at $200 \,A$ and $350\, B$. The relation between $T_A$ and $T_B$ is

• A. $T_A = 4/7\, T_b$
• B. $T_B = 4/7 T_A$
• C. $T_A = 2/7 \,T_B$
• D. $T_B = 2/7 \,T_A$

Answer 1

Answer: (A)

$T_A = 4/7\, T_b$

Answer 2

Here, triple point of water on scale $A = 200A$ Triple point of water on scale $B = 350B$ $200A = 350B - 273.16 \,K$ (given) or $A=\frac{273.16}{200}K$ and $B=\frac{273.16}{350}K$ If $T_{A}$ and $T_{B}$ represent the triple point of water on scales $A$ and $B$, then $\frac{273.16}{200}T_{A}=\frac{273.16}{350}T_{B}$ or $\frac{T_{A}}{T_{B}}=\frac{200}{350}$ or $T_{A}=\frac{4}{7}T_{B}$