The temperature at which the reading of a Fahrenheit thermometer will be double that of a centigrade thermometer is ........ $^\circ$.

The temperature of a body is measured both in ${ }^{\circ} C$ and ${ }^{\circ} F$. $A$ graph is plotted with ${ }^{\circ} F$ on the $X$-axis and ${ }^{\circ} C$ on the $Y$-axis. Then,the cosine of the angle between the graph and the $X$-axis is

At a common temperature,a block of wood and a block of metal feel equally cold or hot. The temperatures of the block of wood and the block of metal are:

$A$ Centigrade and a Fahrenheit thermometer are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers $140\,^{\circ}F$. What is the fall in temperature as registered by the centigrade thermometer?

$A$ 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 $^{\circ}C$)?

On the Celsius scale,the temperature of a body increases by $40^{\circ} C$. The increase in temperature on the Fahrenheit scale is: (in $^{\circ} F$)