At atmospheric pressure, water boils at $100^{\circ}C$. If the pressure is reduced, it will boil at:

$A$ Celsius and a Fahrenheit thermometer are dipped in boiling water. The temperature of water is lowered until the Fahrenheit thermometer shows $140^{\circ}F$. What is the fall in temperature on the Celsius thermometer (in $^{\circ}C$)?

$A$ centigrade and Fahrenheit thermometer are dipped in boiling water. The water temperature is lowered until the Fahrenheit temperature observed is $140^{\circ} F$. At that time the temperature registered by the centigrade thermometer is (in $^{\circ} C$)

In the definition of 'calorie',one calorie is the heat required to raise the temperature of $1\ g$ of water through $1\ ^oC$ in a certain interval of temperature. The temperature interval is

The water on the surface of a lake is just about to freeze. The most likely temperature at the bottom of the lake is (in $^{\circ} C$)

Two absolute scales $A$ and $B$ have triple points of water defined to be $200\; A$ and $350\; B$. What is the relation between $T_{A}$ and $T_{B}$?