Question

which of the following is not true?

• water boils at the same temperature value on both the kelvin and celsius scales.
• a kelvin degree is the same size as a celsius degree.
• the kelvin temperature scale avoids use of negative numbers.
• the degree \symbol\ is not used with the kelvin scale.
• none of the above

Explanation:

1. Analyze each option:

• Option 1: Water boils at \(100^\circ\text{C}\) (Celsius) and \(373.15\,\text{K}\) (Kelvin), so the values are different. This statement is false.
• Option 2: The size of a Kelvin degree (\(\Delta T\) in Kelvin) is the same as a Celsius degree (\(\Delta T\) in Celsius) because the conversion formula is \(T_K=T_C + 273.15\), so the difference between two temperatures is the same in both scales. This statement is true.
• Option 3: The Kelvin scale starts at absolute zero (\(0\,\text{K}\)) and has no negative temperatures (as of standard definitions in thermodynamics for most practical cases), so it avoids negative numbers. This statement is true.
• Option 4: The Kelvin scale uses the unit "kelvin" (symbol \(\text{K}\)) without the degree symbol (\(^\circ\)), unlike Celsius (\(^\circ\text{C}\)) or Fahrenheit (\(^\circ\text{F}\)). This statement is true.
• Option 5: Since Option 1 is not true, this option is incorrect.

Answer:

Water boils at the same temperature value on both the Kelvin and Celsius scales.