In converting Fahrenheit to Kelvin, what is the correct first step?

• A. Subtract 32
• B. Add 273.15
• C. Convert Fahrenheit to Celsius
• D. Multiply by 9/5

Answer: (C)

Converting Fahrenheit to Kelvin starts by turning Fahrenheit into Celsius, because Kelvin is just Celsius shifted by 273.15 (K = C + 273.15). Once you have Celsius, you add 273.15 to get Kelvin. So the first step is to convert Fahrenheit to Celsius. In practice that means subtract 32 and multiply by 5/9 to get Celsius, then add 273.15 to reach Kelvin. Subtracting 32 alone isn’t enough because you must also rescale by 5/9. Adding 273.15 would be done after you have Celsius, not first. Multiplying by 9/5 is used when converting Celsius to Fahrenheit, not Fahrenheit to Celsius.