Physics 2013 JAMB Past Questions - Question 16: Calculate the length which corresponds to a temperature of 20degree if the ice and steam points of an ungraduated thermometer are 400 mm apart

Correct Answer

D

Explanation

To calculate the length on the ungraduated thermometer that corresponds to a temperature of 20 degrees, we need to determine the temperature range covered by 400 mm on the thermometer.

The ice and steam points of the thermometer are typically used as reference points. The ice point corresponds to the temperature at which pure water freezes, which is 0 degrees Celsius (or 32 degrees Fahrenheit). The steam point corresponds to the temperature at which pure water boils, which is 100 degrees Celsius (or 212 degrees Fahrenheit) at standard atmospheric pressure.

Given that the ice and steam points are 400 mm apart on the ungraduated thermometer, we can calculate the temperature range covered by 1 mm on the thermometer as follows:

Temperature range per mm = (100 degrees Celsius - 0 degrees Celsius) / 400 mm
Temperature range per mm = 0.25 degrees Celsius per mm

Now, to find the length on the thermometer that corresponds to a temperature of 20 degrees Celsius, we can use the following formula:

Length = (Temperature - Ice point temperature) / Temperature range per mm

Length = (20 degrees Celsius - 0 degrees Celsius) / 0.25 degrees Celsius per mm
Length = 80 mm

Therefore, a temperature of 20 degrees Celsius on the ungraduated thermometer corresponds to a length of 80 mm.