Of the following thermometers, the one which can be used for measuring a rapidly changing temperature is a

The temperature of a body on the Kelvin scale is $x \ K$. When it is measured by a Fahrenheit thermometer,it is found to be $x \ ^{\circ}F$. The value of $x$ is (nearly):

$A$ Centigrade and a Fahrenheit thermometer are dipped in boiling water. The water is then cooled until the Fahrenheit thermometer reads $140 ^\circ F$. The corresponding drop in temperature as recorded by the Centigrade thermometer is ...... $^\circ C$.

Assertion $(A)$: Rapidly changing temperatures can be measured by thermocouples.
Reason $(R)$: The thermal capacity of the junction of a thermocouple is very small.

The temperature on a Fahrenheit temperature scale that is twice the temperature on a Celsius temperature scale is: (in $^{\circ} F$)

$A$ faulty thermometer has its fixed points marked $5^{\circ}$ and $95^{\circ}$. This thermometer reads the temperature of a body as $59^{\circ}$. Then the correct temperature of the body on the Celsius scale is ........ $^{\circ}$.