List of top Physics Questions on Measurement of temperature

The electrical resistance in ohms of a certain thermometer varies with temperature according to the approximate law :
R = \(R_0\) [1 + α (T – \(T_0\))]
The resistance is 101.6 Ω at the triple-point of water 273.16 K, and 165.5 Ω at the normal melting point of lead (600.5 K). What is the temperature when the resistance is 123.4 Ω ?

1. The triple-point of water is a standard fixed point in modern thermometry. Why ? What is wrong in taking the melting point of ice and the boiling point of water as standard fixed points (as was originally done in the Celsius scale) ?
2. There were two fixed points in the original Celsius scale as mentioned above which were assigned the number 0 °C and 100 °C respectively. On the absolute scale, one of the fixed points is the triple-point of water, which on the Kelvin absolute scale is assigned the number 273.16 K. What is the other fixed point on this (Kelvin) scale ?
3. The absolute temperature (Kelvin scale) T is related to the temperature \(t_c\) on the Celsius scale by
   \(t_c\) = T – 273.15 
   Why do we have 273.15 in this relation, and not 273.16 ?
4. What is the temperature of the triple-point of water on an absolute scale whose unit interval size is equal to that of the Fahrenheit scale ?